xref: /sqlite-3.40.0/src/sqlite.h.in (revision 3438ea3b)
1/*
2** 2001 September 15
3**
4** The author disclaims copyright to this source code.  In place of
5** a legal notice, here is a blessing:
6**
7**    May you do good and not evil.
8**    May you find forgiveness for yourself and forgive others.
9**    May you share freely, never taking more than you give.
10**
11*************************************************************************
12** This header file defines the interface that the SQLite library
13** presents to client programs.
14**
15** @(#) $Id: sqlite.h.in,v 1.198 2007/01/26 00:51:44 drh Exp $
16*/
17#ifndef _SQLITE3_H_
18#define _SQLITE3_H_
19#include <stdarg.h>     /* Needed for the definition of va_list */
20
21/*
22** Make sure we can call this stuff from C++.
23*/
24#ifdef __cplusplus
25extern "C" {
26#endif
27
28/*
29** The version of the SQLite library.
30*/
31#ifdef SQLITE_VERSION
32# undef SQLITE_VERSION
33#endif
34#define SQLITE_VERSION         "--VERS--"
35
36/*
37** The format of the version string is "X.Y.Z<trailing string>", where
38** X is the major version number, Y is the minor version number and Z
39** is the release number. The trailing string is often "alpha" or "beta".
40** For example "3.1.1beta".
41**
42** The SQLITE_VERSION_NUMBER is an integer with the value
43** (X*100000 + Y*1000 + Z). For example, for version "3.1.1beta",
44** SQLITE_VERSION_NUMBER is set to 3001001. To detect if they are using
45** version 3.1.1 or greater at compile time, programs may use the test
46** (SQLITE_VERSION_NUMBER>=3001001).
47*/
48#ifdef SQLITE_VERSION_NUMBER
49# undef SQLITE_VERSION_NUMBER
50#endif
51#define SQLITE_VERSION_NUMBER --VERSION-NUMBER--
52
53/*
54** The version string is also compiled into the library so that a program
55** can check to make sure that the lib*.a file and the *.h file are from
56** the same version.  The sqlite3_libversion() function returns a pointer
57** to the sqlite3_version variable - useful in DLLs which cannot access
58** global variables.
59*/
60extern const char sqlite3_version[];
61const char *sqlite3_libversion(void);
62
63/*
64** Return the value of the SQLITE_VERSION_NUMBER macro when the
65** library was compiled.
66*/
67int sqlite3_libversion_number(void);
68
69/*
70** Each open sqlite database is represented by an instance of the
71** following opaque structure.
72*/
73typedef struct sqlite3 sqlite3;
74
75
76/*
77** Some compilers do not support the "long long" datatype.  So we have
78** to do a typedef that for 64-bit integers that depends on what compiler
79** is being used.
80*/
81#ifdef SQLITE_INT64_TYPE
82  typedef SQLITE_INT64_TYPE sqlite_int64;
83  typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
84#elif defined(_MSC_VER) || defined(__BORLANDC__)
85  typedef __int64 sqlite_int64;
86  typedef unsigned __int64 sqlite_uint64;
87#else
88  typedef long long int sqlite_int64;
89  typedef unsigned long long int sqlite_uint64;
90#endif
91
92/*
93** If compiling for a processor that lacks floating point support,
94** substitute integer for floating-point
95*/
96#ifdef SQLITE_OMIT_FLOATING_POINT
97# define double sqlite_int64
98#endif
99
100/*
101** A function to close the database.
102**
103** Call this function with a pointer to a structure that was previously
104** returned from sqlite3_open() and the corresponding database will by closed.
105**
106** All SQL statements prepared using sqlite3_prepare() or
107** sqlite3_prepare16() must be deallocated using sqlite3_finalize() before
108** this routine is called. Otherwise, SQLITE_BUSY is returned and the
109** database connection remains open.
110*/
111int sqlite3_close(sqlite3 *);
112
113/*
114** The type for a callback function.
115*/
116typedef int (*sqlite3_callback)(void*,int,char**, char**);
117
118/*
119** A function to executes one or more statements of SQL.
120**
121** If one or more of the SQL statements are queries, then
122** the callback function specified by the 3rd parameter is
123** invoked once for each row of the query result.  This callback
124** should normally return 0.  If the callback returns a non-zero
125** value then the query is aborted, all subsequent SQL statements
126** are skipped and the sqlite3_exec() function returns the SQLITE_ABORT.
127**
128** The 1st parameter is an arbitrary pointer that is passed
129** to the callback function as its first parameter.
130**
131** The 2nd parameter to the callback function is the number of
132** columns in the query result.  The 3rd parameter to the callback
133** is an array of strings holding the values for each column.
134** The 4th parameter to the callback is an array of strings holding
135** the names of each column.
136**
137** The callback function may be NULL, even for queries.  A NULL
138** callback is not an error.  It just means that no callback
139** will be invoked.
140**
141** If an error occurs while parsing or evaluating the SQL (but
142** not while executing the callback) then an appropriate error
143** message is written into memory obtained from malloc() and
144** *errmsg is made to point to that message.  The calling function
145** is responsible for freeing the memory that holds the error
146** message.   Use sqlite3_free() for this.  If errmsg==NULL,
147** then no error message is ever written.
148**
149** The return value is is SQLITE_OK if there are no errors and
150** some other return code if there is an error.  The particular
151** return value depends on the type of error.
152**
153** If the query could not be executed because a database file is
154** locked or busy, then this function returns SQLITE_BUSY.  (This
155** behavior can be modified somewhat using the sqlite3_busy_handler()
156** and sqlite3_busy_timeout() functions below.)
157*/
158int sqlite3_exec(
159  sqlite3*,                     /* An open database */
160  const char *sql,              /* SQL to be executed */
161  sqlite3_callback,             /* Callback function */
162  void *,                       /* 1st argument to callback function */
163  char **errmsg                 /* Error msg written here */
164);
165
166/*
167** Return values for sqlite3_exec() and sqlite3_step()
168*/
169#define SQLITE_OK           0   /* Successful result */
170/* beginning-of-error-codes */
171#define SQLITE_ERROR        1   /* SQL error or missing database */
172#define SQLITE_INTERNAL     2   /* NOT USED. Internal logic error in SQLite */
173#define SQLITE_PERM         3   /* Access permission denied */
174#define SQLITE_ABORT        4   /* Callback routine requested an abort */
175#define SQLITE_BUSY         5   /* The database file is locked */
176#define SQLITE_LOCKED       6   /* A table in the database is locked */
177#define SQLITE_NOMEM        7   /* A malloc() failed */
178#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
179#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
180#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
181#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
182#define SQLITE_NOTFOUND    12   /* NOT USED. Table or record not found */
183#define SQLITE_FULL        13   /* Insertion failed because database is full */
184#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
185#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
186#define SQLITE_EMPTY       16   /* Database is empty */
187#define SQLITE_SCHEMA      17   /* The database schema changed */
188#define SQLITE_TOOBIG      18   /* NOT USED. Too much data for one row */
189#define SQLITE_CONSTRAINT  19   /* Abort due to contraint violation */
190#define SQLITE_MISMATCH    20   /* Data type mismatch */
191#define SQLITE_MISUSE      21   /* Library used incorrectly */
192#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
193#define SQLITE_AUTH        23   /* Authorization denied */
194#define SQLITE_FORMAT      24   /* Auxiliary database format error */
195#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
196#define SQLITE_NOTADB      26   /* File opened that is not a database file */
197#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
198#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
199/* end-of-error-codes */
200
201/*
202** Using the sqlite3_extended_result_codes() API, you can cause
203** SQLite to return result codes with additional information in
204** their upper bits.  The lower 8 bits will be the same as the
205** primary result codes above.  But the upper bits might contain
206** more specific error information.
207**
208** To extract the primary result code from an extended result code,
209** simply mask off the lower 8 bits.
210**
211**        primary = extended & 0xff;
212**
213** New result error codes may be added from time to time.  Software
214** that uses the extended result codes should plan accordingly and be
215** sure to always handle new unknown codes gracefully.
216**
217** The SQLITE_OK result code will never be extended.  It will always
218** be exactly zero.
219**
220** The extended result codes always have the primary result code
221** as a prefix.  Primary result codes only contain a single "_"
222** character.  Extended result codes contain two or more "_" characters.
223*/
224#define SQLITE_IOERR_READ          (SQLITE_IOERR | (1<<8))
225#define SQLITE_IOERR_SHORT_READ    (SQLITE_IOERR | (2<<8))
226#define SQLITE_IOERR_WRITE         (SQLITE_IOERR | (3<<8))
227#define SQLITE_IOERR_FSYNC         (SQLITE_IOERR | (4<<8))
228#define SQLITE_IOERR_DIR_FSYNC     (SQLITE_IOERR | (5<<8))
229#define SQLITE_IOERR_TRUNCATE      (SQLITE_IOERR | (6<<8))
230#define SQLITE_IOERR_FSTAT         (SQLITE_IOERR | (7<<8))
231#define SQLITE_IOERR_UNLOCK        (SQLITE_IOERR | (8<<8))
232#define SQLITE_IOERR_RDLOCK        (SQLITE_IOERR | (9<<8))
233
234/*
235** Enable or disable the extended result codes.
236*/
237int sqlite3_extended_result_codes(sqlite3*, int onoff);
238
239/*
240** Each entry in an SQLite table has a unique integer key.  (The key is
241** the value of the INTEGER PRIMARY KEY column if there is such a column,
242** otherwise the key is generated at random.  The unique key is always
243** available as the ROWID, OID, or _ROWID_ column.)  The following routine
244** returns the integer key of the most recent insert in the database.
245**
246** This function is similar to the mysql_insert_id() function from MySQL.
247*/
248sqlite_int64 sqlite3_last_insert_rowid(sqlite3*);
249
250/*
251** This function returns the number of database rows that were changed
252** (or inserted or deleted) by the most recent called sqlite3_exec().
253**
254** All changes are counted, even if they were later undone by a
255** ROLLBACK or ABORT.  Except, changes associated with creating and
256** dropping tables are not counted.
257**
258** If a callback invokes sqlite3_exec() recursively, then the changes
259** in the inner, recursive call are counted together with the changes
260** in the outer call.
261**
262** SQLite implements the command "DELETE FROM table" without a WHERE clause
263** by dropping and recreating the table.  (This is much faster than going
264** through and deleting individual elements form the table.)  Because of
265** this optimization, the change count for "DELETE FROM table" will be
266** zero regardless of the number of elements that were originally in the
267** table. To get an accurate count of the number of rows deleted, use
268** "DELETE FROM table WHERE 1" instead.
269*/
270int sqlite3_changes(sqlite3*);
271
272/*
273** This function returns the number of database rows that have been
274** modified by INSERT, UPDATE or DELETE statements since the database handle
275** was opened. This includes UPDATE, INSERT and DELETE statements executed
276** as part of trigger programs. All changes are counted as soon as the
277** statement that makes them is completed (when the statement handle is
278** passed to sqlite3_reset() or sqlite_finalise()).
279**
280** SQLite implements the command "DELETE FROM table" without a WHERE clause
281** by dropping and recreating the table.  (This is much faster than going
282** through and deleting individual elements form the table.)  Because of
283** this optimization, the change count for "DELETE FROM table" will be
284** zero regardless of the number of elements that were originally in the
285** table. To get an accurate count of the number of rows deleted, use
286** "DELETE FROM table WHERE 1" instead.
287*/
288int sqlite3_total_changes(sqlite3*);
289
290/* This function causes any pending database operation to abort and
291** return at its earliest opportunity.  This routine is typically
292** called in response to a user action such as pressing "Cancel"
293** or Ctrl-C where the user wants a long query operation to halt
294** immediately.
295*/
296void sqlite3_interrupt(sqlite3*);
297
298
299/* These functions return true if the given input string comprises
300** one or more complete SQL statements. For the sqlite3_complete() call,
301** the parameter must be a nul-terminated UTF-8 string. For
302** sqlite3_complete16(), a nul-terminated machine byte order UTF-16 string
303** is required.
304**
305** The algorithm is simple.  If the last token other than spaces
306** and comments is a semicolon, then return true.  otherwise return
307** false.
308*/
309int sqlite3_complete(const char *sql);
310int sqlite3_complete16(const void *sql);
311
312/*
313** This routine identifies a callback function that is invoked
314** whenever an attempt is made to open a database table that is
315** currently locked by another process or thread.  If the busy callback
316** is NULL, then sqlite3_exec() returns SQLITE_BUSY immediately if
317** it finds a locked table.  If the busy callback is not NULL, then
318** sqlite3_exec() invokes the callback with two arguments.  The
319** first argument to the handler is a copy of the void* pointer which
320** is the third argument to this routine.  The second argument to
321** the handler is the number of times that the busy handler has
322** been invoked for this locking event.  If the
323** busy callback returns 0, then sqlite3_exec() immediately returns
324** SQLITE_BUSY.  If the callback returns non-zero, then sqlite3_exec()
325** tries to open the table again and the cycle repeats.
326**
327** The presence of a busy handler does not guarantee that
328** it will be invoked when there is lock contention.
329** If SQLite determines that invoking the busy handler could result in
330** a deadlock, it will return SQLITE_BUSY instead.
331** Consider a scenario where one process is holding a read lock that
332** it is trying to promote to a reserved lock and
333** a second process is holding a reserved lock that it is trying
334** to promote to an exclusive lock.  The first process cannot proceed
335** because it is blocked by the second and the second process cannot
336** proceed because it is blocked by the first.  If both processes
337** invoke the busy handlers, neither will make any progress.  Therefore,
338** SQLite returns SQLITE_BUSY for the first process, hoping that this
339** will induce the first process to release its read lock and allow
340** the second process to proceed.
341**
342** The default busy callback is NULL.
343**
344** Sqlite is re-entrant, so the busy handler may start a new query.
345** (It is not clear why anyone would every want to do this, but it
346** is allowed, in theory.)  But the busy handler may not close the
347** database.  Closing the database from a busy handler will delete
348** data structures out from under the executing query and will
349** probably result in a coredump.
350*/
351int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*);
352
353/*
354** This routine sets a busy handler that sleeps for a while when a
355** table is locked.  The handler will sleep multiple times until
356** at least "ms" milleseconds of sleeping have been done.  After
357** "ms" milleseconds of sleeping, the handler returns 0 which
358** causes sqlite3_exec() to return SQLITE_BUSY.
359**
360** Calling this routine with an argument less than or equal to zero
361** turns off all busy handlers.
362*/
363int sqlite3_busy_timeout(sqlite3*, int ms);
364
365/*
366** This next routine is really just a wrapper around sqlite3_exec().
367** Instead of invoking a user-supplied callback for each row of the
368** result, this routine remembers each row of the result in memory
369** obtained from malloc(), then returns all of the result after the
370** query has finished.
371**
372** As an example, suppose the query result where this table:
373**
374**        Name        | Age
375**        -----------------------
376**        Alice       | 43
377**        Bob         | 28
378**        Cindy       | 21
379**
380** If the 3rd argument were &azResult then after the function returns
381** azResult will contain the following data:
382**
383**        azResult[0] = "Name";
384**        azResult[1] = "Age";
385**        azResult[2] = "Alice";
386**        azResult[3] = "43";
387**        azResult[4] = "Bob";
388**        azResult[5] = "28";
389**        azResult[6] = "Cindy";
390**        azResult[7] = "21";
391**
392** Notice that there is an extra row of data containing the column
393** headers.  But the *nrow return value is still 3.  *ncolumn is
394** set to 2.  In general, the number of values inserted into azResult
395** will be ((*nrow) + 1)*(*ncolumn).
396**
397** After the calling function has finished using the result, it should
398** pass the result data pointer to sqlite3_free_table() in order to
399** release the memory that was malloc-ed.  Because of the way the
400** malloc() happens, the calling function must not try to call
401** free() directly.  Only sqlite3_free_table() is able to release
402** the memory properly and safely.
403**
404** The return value of this routine is the same as from sqlite3_exec().
405*/
406int sqlite3_get_table(
407  sqlite3*,               /* An open database */
408  const char *sql,       /* SQL to be executed */
409  char ***resultp,       /* Result written to a char *[]  that this points to */
410  int *nrow,             /* Number of result rows written here */
411  int *ncolumn,          /* Number of result columns written here */
412  char **errmsg          /* Error msg written here */
413);
414
415/*
416** Call this routine to free the memory that sqlite3_get_table() allocated.
417*/
418void sqlite3_free_table(char **result);
419
420/*
421** The following routines are variants of the "sprintf()" from the
422** standard C library.  The resulting string is written into memory
423** obtained from malloc() so that there is never a possiblity of buffer
424** overflow.  These routines also implement some additional formatting
425** options that are useful for constructing SQL statements.
426**
427** The strings returned by these routines should be freed by calling
428** sqlite3_free().
429**
430** All of the usual printf formatting options apply.  In addition, there
431** is a "%q" option.  %q works like %s in that it substitutes a null-terminated
432** string from the argument list.  But %q also doubles every '\'' character.
433** %q is designed for use inside a string literal.  By doubling each '\''
434** character it escapes that character and allows it to be inserted into
435** the string.
436**
437** For example, so some string variable contains text as follows:
438**
439**      char *zText = "It's a happy day!";
440**
441** We can use this text in an SQL statement as follows:
442**
443**      char *z = sqlite3_mprintf("INSERT INTO TABLES('%q')", zText);
444**      sqlite3_exec(db, z, callback1, 0, 0);
445**      sqlite3_free(z);
446**
447** Because the %q format string is used, the '\'' character in zText
448** is escaped and the SQL generated is as follows:
449**
450**      INSERT INTO table1 VALUES('It''s a happy day!')
451**
452** This is correct.  Had we used %s instead of %q, the generated SQL
453** would have looked like this:
454**
455**      INSERT INTO table1 VALUES('It's a happy day!');
456**
457** This second example is an SQL syntax error.  As a general rule you
458** should always use %q instead of %s when inserting text into a string
459** literal.
460*/
461char *sqlite3_mprintf(const char*,...);
462char *sqlite3_vmprintf(const char*, va_list);
463char *sqlite3_snprintf(int,char*,const char*, ...);
464
465/*
466** SQLite uses its own memory allocator.  On many installations, this
467** memory allocator is identical to the standard malloc()/realloc()/free()
468** and can be used interchangable.  On others, the implementations are
469** different.  For maximum portability, it is best not to mix calls
470** to the standard malloc/realloc/free with the sqlite versions.
471*/
472void *sqlite3_malloc(int);
473void *sqlite3_realloc(void*, int);
474void sqlite3_free(void*);
475
476#ifndef SQLITE_OMIT_AUTHORIZATION
477/*
478** This routine registers a callback with the SQLite library.  The
479** callback is invoked (at compile-time, not at run-time) for each
480** attempt to access a column of a table in the database.  The callback
481** returns SQLITE_OK if access is allowed, SQLITE_DENY if the entire
482** SQL statement should be aborted with an error and SQLITE_IGNORE
483** if the column should be treated as a NULL value.
484*/
485int sqlite3_set_authorizer(
486  sqlite3*,
487  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
488  void *pUserData
489);
490#endif
491
492/*
493** The second parameter to the access authorization function above will
494** be one of the values below.  These values signify what kind of operation
495** is to be authorized.  The 3rd and 4th parameters to the authorization
496** function will be parameters or NULL depending on which of the following
497** codes is used as the second parameter.  The 5th parameter is the name
498** of the database ("main", "temp", etc.) if applicable.  The 6th parameter
499** is the name of the inner-most trigger or view that is responsible for
500** the access attempt or NULL if this access attempt is directly from
501** input SQL code.
502**
503**                                          Arg-3           Arg-4
504*/
505#define SQLITE_COPY                  0   /* Table Name      File Name       */
506#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
507#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
508#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
509#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
510#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
511#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
512#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
513#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
514#define SQLITE_DELETE                9   /* Table Name      NULL            */
515#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
516#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
517#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
518#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
519#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
520#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
521#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
522#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
523#define SQLITE_INSERT               18   /* Table Name      NULL            */
524#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
525#define SQLITE_READ                 20   /* Table Name      Column Name     */
526#define SQLITE_SELECT               21   /* NULL            NULL            */
527#define SQLITE_TRANSACTION          22   /* NULL            NULL            */
528#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
529#define SQLITE_ATTACH               24   /* Filename        NULL            */
530#define SQLITE_DETACH               25   /* Database Name   NULL            */
531#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
532#define SQLITE_REINDEX              27   /* Index Name      NULL            */
533#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
534#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
535#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
536#define SQLITE_FUNCTION             31   /* Function Name   NULL            */
537
538/*
539** The return value of the authorization function should be one of the
540** following constants:
541*/
542/* #define SQLITE_OK  0   // Allow access (This is actually defined above) */
543#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
544#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
545
546/*
547** Register a function for tracing SQL command evaluation.  The function
548** registered by sqlite3_trace() is invoked at the first sqlite3_step()
549** for the evaluation of an SQL statement.  The function registered by
550** sqlite3_profile() runs at the end of each SQL statement and includes
551** information on how long that statement ran.
552**
553** The sqlite3_profile() API is currently considered experimental and
554** is subject to change.
555*/
556void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);
557void *sqlite3_profile(sqlite3*,
558   void(*xProfile)(void*,const char*,sqlite_uint64), void*);
559
560/*
561** This routine configures a callback function - the progress callback - that
562** is invoked periodically during long running calls to sqlite3_exec(),
563** sqlite3_step() and sqlite3_get_table(). An example use for this API is to
564** keep a GUI updated during a large query.
565**
566** The progress callback is invoked once for every N virtual machine opcodes,
567** where N is the second argument to this function. The progress callback
568** itself is identified by the third argument to this function. The fourth
569** argument to this function is a void pointer passed to the progress callback
570** function each time it is invoked.
571**
572** If a call to sqlite3_exec(), sqlite3_step() or sqlite3_get_table() results
573** in less than N opcodes being executed, then the progress callback is not
574** invoked.
575**
576** To remove the progress callback altogether, pass NULL as the third
577** argument to this function.
578**
579** If the progress callback returns a result other than 0, then the current
580** query is immediately terminated and any database changes rolled back. If the
581** query was part of a larger transaction, then the transaction is not rolled
582** back and remains active. The sqlite3_exec() call returns SQLITE_ABORT.
583**
584******* THIS IS AN EXPERIMENTAL API AND IS SUBJECT TO CHANGE ******
585*/
586void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
587
588/*
589** Register a callback function to be invoked whenever a new transaction
590** is committed.  The pArg argument is passed through to the callback.
591** callback.  If the callback function returns non-zero, then the commit
592** is converted into a rollback.
593**
594** If another function was previously registered, its pArg value is returned.
595** Otherwise NULL is returned.
596**
597** Registering a NULL function disables the callback.
598**
599******* THIS IS AN EXPERIMENTAL API AND IS SUBJECT TO CHANGE ******
600*/
601void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
602
603/*
604** Open the sqlite database file "filename".  The "filename" is UTF-8
605** encoded for sqlite3_open() and UTF-16 encoded in the native byte order
606** for sqlite3_open16().  An sqlite3* handle is returned in *ppDb, even
607** if an error occurs. If the database is opened (or created) successfully,
608** then SQLITE_OK is returned. Otherwise an error code is returned. The
609** sqlite3_errmsg() or sqlite3_errmsg16()  routines can be used to obtain
610** an English language description of the error.
611**
612** If the database file does not exist, then a new database is created.
613** The encoding for the database is UTF-8 if sqlite3_open() is called and
614** UTF-16 if sqlite3_open16 is used.
615**
616** Whether or not an error occurs when it is opened, resources associated
617** with the sqlite3* handle should be released by passing it to
618** sqlite3_close() when it is no longer required.
619*/
620int sqlite3_open(
621  const char *filename,   /* Database filename (UTF-8) */
622  sqlite3 **ppDb          /* OUT: SQLite db handle */
623);
624int sqlite3_open16(
625  const void *filename,   /* Database filename (UTF-16) */
626  sqlite3 **ppDb          /* OUT: SQLite db handle */
627);
628
629/*
630** Return the error code for the most recent sqlite3_* API call associated
631** with sqlite3 handle 'db'. SQLITE_OK is returned if the most recent
632** API call was successful.
633**
634** Calls to many sqlite3_* functions set the error code and string returned
635** by sqlite3_errcode(), sqlite3_errmsg() and sqlite3_errmsg16()
636** (overwriting the previous values). Note that calls to sqlite3_errcode(),
637** sqlite3_errmsg() and sqlite3_errmsg16() themselves do not affect the
638** results of future invocations.
639**
640** Assuming no other intervening sqlite3_* API calls are made, the error
641** code returned by this function is associated with the same error as
642** the strings  returned by sqlite3_errmsg() and sqlite3_errmsg16().
643*/
644int sqlite3_errcode(sqlite3 *db);
645
646/*
647** Return a pointer to a UTF-8 encoded string describing in english the
648** error condition for the most recent sqlite3_* API call. The returned
649** string is always terminated by an 0x00 byte.
650**
651** The string "not an error" is returned when the most recent API call was
652** successful.
653*/
654const char *sqlite3_errmsg(sqlite3*);
655
656/*
657** Return a pointer to a UTF-16 native byte order encoded string describing
658** in english the error condition for the most recent sqlite3_* API call.
659** The returned string is always terminated by a pair of 0x00 bytes.
660**
661** The string "not an error" is returned when the most recent API call was
662** successful.
663*/
664const void *sqlite3_errmsg16(sqlite3*);
665
666/*
667** An instance of the following opaque structure is used to represent
668** a compiled SQL statment.
669*/
670typedef struct sqlite3_stmt sqlite3_stmt;
671
672/*
673** To execute an SQL query, it must first be compiled into a byte-code
674** program using one of the following routines. The only difference between
675** them is that the second argument, specifying the SQL statement to
676** compile, is assumed to be encoded in UTF-8 for the sqlite3_prepare()
677** function and UTF-16 for sqlite3_prepare16().
678**
679** The first parameter "db" is an SQLite database handle. The second
680** parameter "zSql" is the statement to be compiled, encoded as either
681** UTF-8 or UTF-16 (see above). If the next parameter, "nBytes", is less
682** than zero, then zSql is read up to the first nul terminator.  If
683** "nBytes" is not less than zero, then it is the length of the string zSql
684** in bytes (not characters).
685**
686** *pzTail is made to point to the first byte past the end of the first
687** SQL statement in zSql.  This routine only compiles the first statement
688** in zSql, so *pzTail is left pointing to what remains uncompiled.
689**
690** *ppStmt is left pointing to a compiled SQL statement that can be
691** executed using sqlite3_step().  Or if there is an error, *ppStmt may be
692** set to NULL.  If the input text contained no SQL (if the input is and
693** empty string or a comment) then *ppStmt is set to NULL.
694**
695** On success, SQLITE_OK is returned.  Otherwise an error code is returned.
696*/
697int sqlite3_prepare(
698  sqlite3 *db,            /* Database handle */
699  const char *zSql,       /* SQL statement, UTF-8 encoded */
700  int nBytes,             /* Length of zSql in bytes. */
701  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
702  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
703);
704int sqlite3_prepare16(
705  sqlite3 *db,            /* Database handle */
706  const void *zSql,       /* SQL statement, UTF-16 encoded */
707  int nBytes,             /* Length of zSql in bytes. */
708  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
709  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
710);
711
712/*
713** Newer versions of the prepare API work just like the legacy versions
714** but with one exception:  The a copy of the SQL text is saved in the
715** sqlite3_stmt structure that is returned.  If this copy exists, it
716** modifieds the behavior of sqlite3_step() slightly.  First, sqlite3_step()
717** will no longer return an SQLITE_SCHEMA error but will instead automatically
718** rerun the compiler to rebuild the prepared statement.  Secondly,
719** sqlite3_step() now turns a full result code - the result code that
720** use used to have to call sqlite3_reset() to get.
721*/
722int sqlite3_prepare_v2(
723  sqlite3 *db,            /* Database handle */
724  const char *zSql,       /* SQL statement, UTF-8 encoded */
725  int nBytes,             /* Length of zSql in bytes. */
726  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
727  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
728);
729int sqlite3_prepare16_v2(
730  sqlite3 *db,            /* Database handle */
731  const void *zSql,       /* SQL statement, UTF-16 encoded */
732  int nBytes,             /* Length of zSql in bytes. */
733  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
734  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
735);
736
737/*
738** Pointers to the following two opaque structures are used to communicate
739** with the implementations of user-defined functions.
740*/
741typedef struct sqlite3_context sqlite3_context;
742typedef struct Mem sqlite3_value;
743
744/*
745** In the SQL strings input to sqlite3_prepare() and sqlite3_prepare16(),
746** one or more literals can be replace by parameters "?" or ":AAA" or
747** "$VVV" where AAA is an identifer and VVV is a variable name according
748** to the syntax rules of the TCL programming language.
749** The value of these parameters (also called "host parameter names") can
750** be set using the routines listed below.
751**
752** In every case, the first parameter is a pointer to the sqlite3_stmt
753** structure returned from sqlite3_prepare().  The second parameter is the
754** index of the parameter.  The first parameter as an index of 1.  For
755** named parameters (":AAA" or "$VVV") you can use
756** sqlite3_bind_parameter_index() to get the correct index value given
757** the parameters name.  If the same named parameter occurs more than
758** once, it is assigned the same index each time.
759**
760** The fifth parameter to sqlite3_bind_blob(), sqlite3_bind_text(), and
761** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
762** text after SQLite has finished with it.  If the fifth argument is the
763** special value SQLITE_STATIC, then the library assumes that the information
764** is in static, unmanaged space and does not need to be freed.  If the
765** fifth argument has the value SQLITE_TRANSIENT, then SQLite makes its
766** own private copy of the data.
767**
768** The sqlite3_bind_* routine must be called before sqlite3_step() after
769** an sqlite3_prepare() or sqlite3_reset().  Unbound parameterss are
770** interpreted as NULL.
771*/
772int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
773int sqlite3_bind_double(sqlite3_stmt*, int, double);
774int sqlite3_bind_int(sqlite3_stmt*, int, int);
775int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite_int64);
776int sqlite3_bind_null(sqlite3_stmt*, int);
777int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*));
778int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
779int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
780
781/*
782** Return the number of parameters in a compiled SQL statement.  This
783** routine was added to support DBD::SQLite.
784*/
785int sqlite3_bind_parameter_count(sqlite3_stmt*);
786
787/*
788** Return the name of the i-th parameter.  Ordinary parameters "?" are
789** nameless and a NULL is returned.  For parameters of the form :AAA or
790** $VVV the complete text of the parameter name is returned, including
791** the initial ":" or "$".  NULL is returned if the index is out of range.
792*/
793const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
794
795/*
796** Return the index of a parameter with the given name.  The name
797** must match exactly.  If no parameter with the given name is found,
798** return 0.
799*/
800int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
801
802/*
803** Set all the parameters in the compiled SQL statement to NULL.
804*/
805int sqlite3_clear_bindings(sqlite3_stmt*);
806
807/*
808** Return the number of columns in the result set returned by the compiled
809** SQL statement. This routine returns 0 if pStmt is an SQL statement
810** that does not return data (for example an UPDATE).
811*/
812int sqlite3_column_count(sqlite3_stmt *pStmt);
813
814/*
815** The first parameter is a compiled SQL statement. This function returns
816** the column heading for the Nth column of that statement, where N is the
817** second function parameter.  The string returned is UTF-8 for
818** sqlite3_column_name() and UTF-16 for sqlite3_column_name16().
819*/
820const char *sqlite3_column_name(sqlite3_stmt*,int);
821const void *sqlite3_column_name16(sqlite3_stmt*,int);
822
823/*
824** The first parameter to the following calls is a compiled SQL statement.
825** These functions return information about the Nth column returned by
826** the statement, where N is the second function argument.
827**
828** If the Nth column returned by the statement is not a column value,
829** then all of the functions return NULL. Otherwise, the return the
830** name of the attached database, table and column that the expression
831** extracts a value from.
832**
833** As with all other SQLite APIs, those postfixed with "16" return UTF-16
834** encoded strings, the other functions return UTF-8. The memory containing
835** the returned strings is valid until the statement handle is finalized().
836**
837** These APIs are only available if the library was compiled with the
838** SQLITE_ENABLE_COLUMN_METADATA preprocessor symbol defined.
839*/
840const char *sqlite3_column_database_name(sqlite3_stmt*,int);
841const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
842const char *sqlite3_column_table_name(sqlite3_stmt*,int);
843const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
844const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
845const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
846
847/*
848** The first parameter is a compiled SQL statement. If this statement
849** is a SELECT statement, the Nth column of the returned result set
850** of the SELECT is a table column then the declared type of the table
851** column is returned. If the Nth column of the result set is not at table
852** column, then a NULL pointer is returned. The returned string is always
853** UTF-8 encoded. For example, in the database schema:
854**
855** CREATE TABLE t1(c1 VARIANT);
856**
857** And the following statement compiled:
858**
859** SELECT c1 + 1, c1 FROM t1;
860**
861** Then this routine would return the string "VARIANT" for the second
862** result column (i==1), and a NULL pointer for the first result column
863** (i==0).
864*/
865const char *sqlite3_column_decltype(sqlite3_stmt *, int i);
866
867/*
868** The first parameter is a compiled SQL statement. If this statement
869** is a SELECT statement, the Nth column of the returned result set
870** of the SELECT is a table column then the declared type of the table
871** column is returned. If the Nth column of the result set is not at table
872** column, then a NULL pointer is returned. The returned string is always
873** UTF-16 encoded. For example, in the database schema:
874**
875** CREATE TABLE t1(c1 INTEGER);
876**
877** And the following statement compiled:
878**
879** SELECT c1 + 1, c1 FROM t1;
880**
881** Then this routine would return the string "INTEGER" for the second
882** result column (i==1), and a NULL pointer for the first result column
883** (i==0).
884*/
885const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
886
887/*
888** After an SQL query has been compiled with a call to either
889** sqlite3_prepare() or sqlite3_prepare16(), then this function must be
890** called one or more times to execute the statement.
891**
892** The return value will be either SQLITE_BUSY, SQLITE_DONE,
893** SQLITE_ROW, SQLITE_ERROR, or SQLITE_MISUSE.
894**
895** SQLITE_BUSY means that the database engine attempted to open
896** a locked database and there is no busy callback registered.
897** Call sqlite3_step() again to retry the open.
898**
899** SQLITE_DONE means that the statement has finished executing
900** successfully.  sqlite3_step() should not be called again on this virtual
901** machine.
902**
903** If the SQL statement being executed returns any data, then
904** SQLITE_ROW is returned each time a new row of data is ready
905** for processing by the caller. The values may be accessed using
906** the sqlite3_column_*() functions described below. sqlite3_step()
907** is called again to retrieve the next row of data.
908**
909** SQLITE_ERROR means that a run-time error (such as a constraint
910** violation) has occurred.  sqlite3_step() should not be called again on
911** the VM. More information may be found by calling sqlite3_errmsg().
912**
913** SQLITE_MISUSE means that the this routine was called inappropriately.
914** Perhaps it was called on a virtual machine that had already been
915** finalized or on one that had previously returned SQLITE_ERROR or
916** SQLITE_DONE.  Or it could be the case the the same database connection
917** is being used simulataneously by two or more threads.
918*/
919int sqlite3_step(sqlite3_stmt*);
920
921/*
922** Return the number of values in the current row of the result set.
923**
924** After a call to sqlite3_step() that returns SQLITE_ROW, this routine
925** will return the same value as the sqlite3_column_count() function.
926** After sqlite3_step() has returned an SQLITE_DONE, SQLITE_BUSY or
927** error code, or before sqlite3_step() has been called on a
928** compiled SQL statement, this routine returns zero.
929*/
930int sqlite3_data_count(sqlite3_stmt *pStmt);
931
932/*
933** Values are stored in the database in one of the following fundamental
934** types.
935*/
936#define SQLITE_INTEGER  1
937#define SQLITE_FLOAT    2
938/* #define SQLITE_TEXT  3  // See below */
939#define SQLITE_BLOB     4
940#define SQLITE_NULL     5
941
942/*
943** SQLite version 2 defines SQLITE_TEXT differently.  To allow both
944** version 2 and version 3 to be included, undefine them both if a
945** conflict is seen.  Define SQLITE3_TEXT to be the version 3 value.
946*/
947#ifdef SQLITE_TEXT
948# undef SQLITE_TEXT
949#else
950# define SQLITE_TEXT     3
951#endif
952#define SQLITE3_TEXT     3
953
954/*
955** The next group of routines returns information about the information
956** in a single column of the current result row of a query.  In every
957** case the first parameter is a pointer to the SQL statement that is being
958** executed (the sqlite_stmt* that was returned from sqlite3_prepare()) and
959** the second argument is the index of the column for which information
960** should be returned.  iCol is zero-indexed.  The left-most column as an
961** index of 0.
962**
963** If the SQL statement is not currently point to a valid row, or if the
964** the colulmn index is out of range, the result is undefined.
965**
966** These routines attempt to convert the value where appropriate.  For
967** example, if the internal representation is FLOAT and a text result
968** is requested, sprintf() is used internally to do the conversion
969** automatically.  The following table details the conversions that
970** are applied:
971**
972**    Internal Type    Requested Type     Conversion
973**    -------------    --------------    --------------------------
974**       NULL             INTEGER         Result is 0
975**       NULL             FLOAT           Result is 0.0
976**       NULL             TEXT            Result is an empty string
977**       NULL             BLOB            Result is a zero-length BLOB
978**       INTEGER          FLOAT           Convert from integer to float
979**       INTEGER          TEXT            ASCII rendering of the integer
980**       INTEGER          BLOB            Same as for INTEGER->TEXT
981**       FLOAT            INTEGER         Convert from float to integer
982**       FLOAT            TEXT            ASCII rendering of the float
983**       FLOAT            BLOB            Same as FLOAT->TEXT
984**       TEXT             INTEGER         Use atoi()
985**       TEXT             FLOAT           Use atof()
986**       TEXT             BLOB            No change
987**       BLOB             INTEGER         Convert to TEXT then use atoi()
988**       BLOB             FLOAT           Convert to TEXT then use atof()
989**       BLOB             TEXT            Add a \000 terminator if needed
990**
991** The following access routines are provided:
992**
993** _type()     Return the datatype of the result.  This is one of
994**             SQLITE_INTEGER, SQLITE_FLOAT, SQLITE_TEXT, SQLITE_BLOB,
995**             or SQLITE_NULL.
996** _blob()     Return the value of a BLOB.
997** _bytes()    Return the number of bytes in a BLOB value or the number
998**             of bytes in a TEXT value represented as UTF-8.  The \000
999**             terminator is included in the byte count for TEXT values.
1000** _bytes16()  Return the number of bytes in a BLOB value or the number
1001**             of bytes in a TEXT value represented as UTF-16.  The \u0000
1002**             terminator is included in the byte count for TEXT values.
1003** _double()   Return a FLOAT value.
1004** _int()      Return an INTEGER value in the host computer's native
1005**             integer representation.  This might be either a 32- or 64-bit
1006**             integer depending on the host.
1007** _int64()    Return an INTEGER value as a 64-bit signed integer.
1008** _text()     Return the value as UTF-8 text.
1009** _text16()   Return the value as UTF-16 text.
1010*/
1011const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
1012int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
1013int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
1014double sqlite3_column_double(sqlite3_stmt*, int iCol);
1015int sqlite3_column_int(sqlite3_stmt*, int iCol);
1016sqlite_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
1017const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
1018const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
1019int sqlite3_column_type(sqlite3_stmt*, int iCol);
1020int sqlite3_column_numeric_type(sqlite3_stmt*, int iCol);
1021sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
1022
1023/*
1024** The sqlite3_finalize() function is called to delete a compiled
1025** SQL statement obtained by a previous call to sqlite3_prepare()
1026** or sqlite3_prepare16(). If the statement was executed successfully, or
1027** not executed at all, then SQLITE_OK is returned. If execution of the
1028** statement failed then an error code is returned.
1029**
1030** This routine can be called at any point during the execution of the
1031** virtual machine.  If the virtual machine has not completed execution
1032** when this routine is called, that is like encountering an error or
1033** an interrupt.  (See sqlite3_interrupt().)  Incomplete updates may be
1034** rolled back and transactions cancelled,  depending on the circumstances,
1035** and the result code returned will be SQLITE_ABORT.
1036*/
1037int sqlite3_finalize(sqlite3_stmt *pStmt);
1038
1039/*
1040** The sqlite3_reset() function is called to reset a compiled SQL
1041** statement obtained by a previous call to sqlite3_prepare() or
1042** sqlite3_prepare16() back to it's initial state, ready to be re-executed.
1043** Any SQL statement variables that had values bound to them using
1044** the sqlite3_bind_*() API retain their values.
1045*/
1046int sqlite3_reset(sqlite3_stmt *pStmt);
1047
1048/*
1049** The following two functions are used to add user functions or aggregates
1050** implemented in C to the SQL langauge interpreted by SQLite. The
1051** difference only between the two is that the second parameter, the
1052** name of the (scalar) function or aggregate, is encoded in UTF-8 for
1053** sqlite3_create_function() and UTF-16 for sqlite3_create_function16().
1054**
1055** The first argument is the database handle that the new function or
1056** aggregate is to be added to. If a single program uses more than one
1057** database handle internally, then user functions or aggregates must
1058** be added individually to each database handle with which they will be
1059** used.
1060**
1061** The third parameter is the number of arguments that the function or
1062** aggregate takes. If this parameter is negative, then the function or
1063** aggregate may take any number of arguments.
1064**
1065** The fourth parameter is one of SQLITE_UTF* values defined below,
1066** indicating the encoding that the function is most likely to handle
1067** values in.  This does not change the behaviour of the programming
1068** interface. However, if two versions of the same function are registered
1069** with different encoding values, SQLite invokes the version likely to
1070** minimize conversions between text encodings.
1071**
1072** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are
1073** pointers to user implemented C functions that implement the user
1074** function or aggregate. A scalar function requires an implementation of
1075** the xFunc callback only, NULL pointers should be passed as the xStep
1076** and xFinal parameters. An aggregate function requires an implementation
1077** of xStep and xFinal, but NULL should be passed for xFunc. To delete an
1078** existing user function or aggregate, pass NULL for all three function
1079** callback. Specifying an inconstent set of callback values, such as an
1080** xFunc and an xFinal, or an xStep but no xFinal, SQLITE_ERROR is
1081** returned.
1082*/
1083int sqlite3_create_function(
1084  sqlite3 *,
1085  const char *zFunctionName,
1086  int nArg,
1087  int eTextRep,
1088  void*,
1089  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
1090  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1091  void (*xFinal)(sqlite3_context*)
1092);
1093int sqlite3_create_function16(
1094  sqlite3*,
1095  const void *zFunctionName,
1096  int nArg,
1097  int eTextRep,
1098  void*,
1099  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
1100  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
1101  void (*xFinal)(sqlite3_context*)
1102);
1103
1104/*
1105** This function is deprecated.  Do not use it.  It continues to exist
1106** so as not to break legacy code.  But new code should avoid using it.
1107*/
1108int sqlite3_aggregate_count(sqlite3_context*);
1109
1110/*
1111** The next group of routines returns information about parameters to
1112** a user-defined function.  Function implementations use these routines
1113** to access their parameters.  These routines are the same as the
1114** sqlite3_column_* routines except that these routines take a single
1115** sqlite3_value* pointer instead of an sqlite3_stmt* and an integer
1116** column number.
1117*/
1118const void *sqlite3_value_blob(sqlite3_value*);
1119int sqlite3_value_bytes(sqlite3_value*);
1120int sqlite3_value_bytes16(sqlite3_value*);
1121double sqlite3_value_double(sqlite3_value*);
1122int sqlite3_value_int(sqlite3_value*);
1123sqlite_int64 sqlite3_value_int64(sqlite3_value*);
1124const unsigned char *sqlite3_value_text(sqlite3_value*);
1125const void *sqlite3_value_text16(sqlite3_value*);
1126const void *sqlite3_value_text16le(sqlite3_value*);
1127const void *sqlite3_value_text16be(sqlite3_value*);
1128int sqlite3_value_type(sqlite3_value*);
1129int sqlite3_value_numeric_type(sqlite3_value*);
1130
1131/*
1132** Aggregate functions use the following routine to allocate
1133** a structure for storing their state.  The first time this routine
1134** is called for a particular aggregate, a new structure of size nBytes
1135** is allocated, zeroed, and returned.  On subsequent calls (for the
1136** same aggregate instance) the same buffer is returned.  The implementation
1137** of the aggregate can use the returned buffer to accumulate data.
1138**
1139** The buffer allocated is freed automatically by SQLite.
1140*/
1141void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
1142
1143/*
1144** The pUserData parameter to the sqlite3_create_function()
1145** routine used to register user functions is available to
1146** the implementation of the function using this call.
1147*/
1148void *sqlite3_user_data(sqlite3_context*);
1149
1150/*
1151** The following two functions may be used by scalar user functions to
1152** associate meta-data with argument values. If the same value is passed to
1153** multiple invocations of the user-function during query execution, under
1154** some circumstances the associated meta-data may be preserved. This may
1155** be used, for example, to add a regular-expression matching scalar
1156** function. The compiled version of the regular expression is stored as
1157** meta-data associated with the SQL value passed as the regular expression
1158** pattern.
1159**
1160** Calling sqlite3_get_auxdata() returns a pointer to the meta data
1161** associated with the Nth argument value to the current user function
1162** call, where N is the second parameter. If no meta-data has been set for
1163** that value, then a NULL pointer is returned.
1164**
1165** The sqlite3_set_auxdata() is used to associate meta data with a user
1166** function argument. The third parameter is a pointer to the meta data
1167** to be associated with the Nth user function argument value. The fourth
1168** parameter specifies a 'delete function' that will be called on the meta
1169** data pointer to release it when it is no longer required. If the delete
1170** function pointer is NULL, it is not invoked.
1171**
1172** In practice, meta-data is preserved between function calls for
1173** expressions that are constant at compile time. This includes literal
1174** values and SQL variables.
1175*/
1176void *sqlite3_get_auxdata(sqlite3_context*, int);
1177void sqlite3_set_auxdata(sqlite3_context*, int, void*, void (*)(void*));
1178
1179
1180/*
1181** These are special value for the destructor that is passed in as the
1182** final argument to routines like sqlite3_result_blob().  If the destructor
1183** argument is SQLITE_STATIC, it means that the content pointer is constant
1184** and will never change.  It does not need to be destroyed.  The
1185** SQLITE_TRANSIENT value means that the content will likely change in
1186** the near future and that SQLite should make its own private copy of
1187** the content before returning.
1188**
1189** The typedef is necessary to work around problems in certain
1190** C++ compilers.  See ticket #2191.
1191*/
1192typedef void (*sqlite3_destructor_type)(void*);
1193#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
1194#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
1195
1196/*
1197** User-defined functions invoke the following routines in order to
1198** set their return value.
1199*/
1200void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
1201void sqlite3_result_double(sqlite3_context*, double);
1202void sqlite3_result_error(sqlite3_context*, const char*, int);
1203void sqlite3_result_error16(sqlite3_context*, const void*, int);
1204void sqlite3_result_int(sqlite3_context*, int);
1205void sqlite3_result_int64(sqlite3_context*, sqlite_int64);
1206void sqlite3_result_null(sqlite3_context*);
1207void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
1208void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
1209void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
1210void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
1211void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
1212
1213/*
1214** These are the allowed values for the eTextRep argument to
1215** sqlite3_create_collation and sqlite3_create_function.
1216*/
1217#define SQLITE_UTF8           1
1218#define SQLITE_UTF16LE        2
1219#define SQLITE_UTF16BE        3
1220#define SQLITE_UTF16          4    /* Use native byte order */
1221#define SQLITE_ANY            5    /* sqlite3_create_function only */
1222#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
1223
1224/*
1225** These two functions are used to add new collation sequences to the
1226** sqlite3 handle specified as the first argument.
1227**
1228** The name of the new collation sequence is specified as a UTF-8 string
1229** for sqlite3_create_collation() and a UTF-16 string for
1230** sqlite3_create_collation16(). In both cases the name is passed as the
1231** second function argument.
1232**
1233** The third argument must be one of the constants SQLITE_UTF8,
1234** SQLITE_UTF16LE or SQLITE_UTF16BE, indicating that the user-supplied
1235** routine expects to be passed pointers to strings encoded using UTF-8,
1236** UTF-16 little-endian or UTF-16 big-endian respectively.
1237**
1238** A pointer to the user supplied routine must be passed as the fifth
1239** argument. If it is NULL, this is the same as deleting the collation
1240** sequence (so that SQLite cannot call it anymore). Each time the user
1241** supplied function is invoked, it is passed a copy of the void* passed as
1242** the fourth argument to sqlite3_create_collation() or
1243** sqlite3_create_collation16() as its first parameter.
1244**
1245** The remaining arguments to the user-supplied routine are two strings,
1246** each represented by a [length, data] pair and encoded in the encoding
1247** that was passed as the third argument when the collation sequence was
1248** registered. The user routine should return negative, zero or positive if
1249** the first string is less than, equal to, or greater than the second
1250** string. i.e. (STRING1 - STRING2).
1251*/
1252int sqlite3_create_collation(
1253  sqlite3*,
1254  const char *zName,
1255  int eTextRep,
1256  void*,
1257  int(*xCompare)(void*,int,const void*,int,const void*)
1258);
1259int sqlite3_create_collation16(
1260  sqlite3*,
1261  const char *zName,
1262  int eTextRep,
1263  void*,
1264  int(*xCompare)(void*,int,const void*,int,const void*)
1265);
1266
1267/*
1268** To avoid having to register all collation sequences before a database
1269** can be used, a single callback function may be registered with the
1270** database handle to be called whenever an undefined collation sequence is
1271** required.
1272**
1273** If the function is registered using the sqlite3_collation_needed() API,
1274** then it is passed the names of undefined collation sequences as strings
1275** encoded in UTF-8. If sqlite3_collation_needed16() is used, the names
1276** are passed as UTF-16 in machine native byte order. A call to either
1277** function replaces any existing callback.
1278**
1279** When the user-function is invoked, the first argument passed is a copy
1280** of the second argument to sqlite3_collation_needed() or
1281** sqlite3_collation_needed16(). The second argument is the database
1282** handle. The third argument is one of SQLITE_UTF8, SQLITE_UTF16BE or
1283** SQLITE_UTF16LE, indicating the most desirable form of the collation
1284** sequence function required. The fourth parameter is the name of the
1285** required collation sequence.
1286**
1287** The collation sequence is returned to SQLite by a collation-needed
1288** callback using the sqlite3_create_collation() or
1289** sqlite3_create_collation16() APIs, described above.
1290*/
1291int sqlite3_collation_needed(
1292  sqlite3*,
1293  void*,
1294  void(*)(void*,sqlite3*,int eTextRep,const char*)
1295);
1296int sqlite3_collation_needed16(
1297  sqlite3*,
1298  void*,
1299  void(*)(void*,sqlite3*,int eTextRep,const void*)
1300);
1301
1302/*
1303** Specify the key for an encrypted database.  This routine should be
1304** called right after sqlite3_open().
1305**
1306** The code to implement this API is not available in the public release
1307** of SQLite.
1308*/
1309int sqlite3_key(
1310  sqlite3 *db,                   /* Database to be rekeyed */
1311  const void *pKey, int nKey     /* The key */
1312);
1313
1314/*
1315** Change the key on an open database.  If the current database is not
1316** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
1317** database is decrypted.
1318**
1319** The code to implement this API is not available in the public release
1320** of SQLite.
1321*/
1322int sqlite3_rekey(
1323  sqlite3 *db,                   /* Database to be rekeyed */
1324  const void *pKey, int nKey     /* The new key */
1325);
1326
1327/*
1328** Sleep for a little while. The second parameter is the number of
1329** miliseconds to sleep for.
1330**
1331** If the operating system does not support sleep requests with
1332** milisecond time resolution, then the time will be rounded up to
1333** the nearest second. The number of miliseconds of sleep actually
1334** requested from the operating system is returned.
1335*/
1336int sqlite3_sleep(int);
1337
1338/*
1339** Return TRUE (non-zero) if the statement supplied as an argument needs
1340** to be recompiled.  A statement needs to be recompiled whenever the
1341** execution environment changes in a way that would alter the program
1342** that sqlite3_prepare() generates.  For example, if new functions or
1343** collating sequences are registered or if an authorizer function is
1344** added or changed.
1345**
1346*/
1347int sqlite3_expired(sqlite3_stmt*);
1348
1349/*
1350** Move all bindings from the first prepared statement over to the second.
1351** This routine is useful, for example, if the first prepared statement
1352** fails with an SQLITE_SCHEMA error.  The same SQL can be prepared into
1353** the second prepared statement then all of the bindings transfered over
1354** to the second statement before the first statement is finalized.
1355*/
1356int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
1357
1358/*
1359** If the following global variable is made to point to a
1360** string which is the name of a directory, then all temporary files
1361** created by SQLite will be placed in that directory.  If this variable
1362** is NULL pointer, then SQLite does a search for an appropriate temporary
1363** file directory.
1364**
1365** Once sqlite3_open() has been called, changing this variable will invalidate
1366** the current temporary database, if any.
1367*/
1368extern char *sqlite3_temp_directory;
1369
1370/*
1371** This function is called to recover from a malloc() failure that occured
1372** within the SQLite library. Normally, after a single malloc() fails the
1373** library refuses to function (all major calls return SQLITE_NOMEM).
1374** This function restores the library state so that it can be used again.
1375**
1376** All existing statements (sqlite3_stmt pointers) must be finalized or
1377** reset before this call is made. Otherwise, SQLITE_BUSY is returned.
1378** If any in-memory databases are in use, either as a main or TEMP
1379** database, SQLITE_ERROR is returned. In either of these cases, the
1380** library is not reset and remains unusable.
1381**
1382** This function is *not* threadsafe. Calling this from within a threaded
1383** application when threads other than the caller have used SQLite is
1384** dangerous and will almost certainly result in malfunctions.
1385**
1386** This functionality can be omitted from a build by defining the
1387** SQLITE_OMIT_GLOBALRECOVER at compile time.
1388*/
1389int sqlite3_global_recover(void);
1390
1391/*
1392** Test to see whether or not the database connection is in autocommit
1393** mode.  Return TRUE if it is and FALSE if not.  Autocommit mode is on
1394** by default.  Autocommit is disabled by a BEGIN statement and reenabled
1395** by the next COMMIT or ROLLBACK.
1396*/
1397int sqlite3_get_autocommit(sqlite3*);
1398
1399/*
1400** Return the sqlite3* database handle to which the prepared statement given
1401** in the argument belongs.  This is the same database handle that was
1402** the first argument to the sqlite3_prepare() that was used to create
1403** the statement in the first place.
1404*/
1405sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
1406
1407/*
1408** Register a callback function with the database connection identified by the
1409** first argument to be invoked whenever a row is updated, inserted or deleted.
1410** Any callback set by a previous call to this function for the same
1411** database connection is overridden.
1412**
1413** The second argument is a pointer to the function to invoke when a
1414** row is updated, inserted or deleted. The first argument to the callback is
1415** a copy of the third argument to sqlite3_update_hook. The second callback
1416** argument is one of SQLITE_INSERT, SQLITE_DELETE or SQLITE_UPDATE, depending
1417** on the operation that caused the callback to be invoked. The third and
1418** fourth arguments to the callback contain pointers to the database and
1419** table name containing the affected row. The final callback parameter is
1420** the rowid of the row. In the case of an update, this is the rowid after
1421** the update takes place.
1422**
1423** The update hook is not invoked when internal system tables are
1424** modified (i.e. sqlite_master and sqlite_sequence).
1425**
1426** If another function was previously registered, its pArg value is returned.
1427** Otherwise NULL is returned.
1428*/
1429void *sqlite3_update_hook(
1430  sqlite3*,
1431  void(*)(void *,int ,char const *,char const *,sqlite_int64),
1432  void*
1433);
1434
1435/*
1436** Register a callback to be invoked whenever a transaction is rolled
1437** back.
1438**
1439** The new callback function overrides any existing rollback-hook
1440** callback. If there was an existing callback, then it's pArg value
1441** (the third argument to sqlite3_rollback_hook() when it was registered)
1442** is returned. Otherwise, NULL is returned.
1443**
1444** For the purposes of this API, a transaction is said to have been
1445** rolled back if an explicit "ROLLBACK" statement is executed, or
1446** an error or constraint causes an implicit rollback to occur. The
1447** callback is not invoked if a transaction is automatically rolled
1448** back because the database connection is closed.
1449*/
1450void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
1451
1452/*
1453** This function is only available if the library is compiled without
1454** the SQLITE_OMIT_SHARED_CACHE macro defined. It is used to enable or
1455** disable (if the argument is true or false, respectively) the
1456** "shared pager" feature.
1457*/
1458int sqlite3_enable_shared_cache(int);
1459
1460/*
1461** Attempt to free N bytes of heap memory by deallocating non-essential
1462** memory allocations held by the database library (example: memory
1463** used to cache database pages to improve performance).
1464**
1465** This function is not a part of standard builds.  It is only created
1466** if SQLite is compiled with the SQLITE_ENABLE_MEMORY_MANAGEMENT macro.
1467*/
1468int sqlite3_release_memory(int);
1469
1470/*
1471** Place a "soft" limit on the amount of heap memory that may be allocated by
1472** SQLite within the current thread. If an internal allocation is requested
1473** that would exceed the specified limit, sqlite3_release_memory() is invoked
1474** one or more times to free up some space before the allocation is made.
1475**
1476** The limit is called "soft", because if sqlite3_release_memory() cannot free
1477** sufficient memory to prevent the limit from being exceeded, the memory is
1478** allocated anyway and the current operation proceeds.
1479**
1480** This function is only available if the library was compiled with the
1481** SQLITE_ENABLE_MEMORY_MANAGEMENT option set.
1482** memory-management has been enabled.
1483*/
1484void sqlite3_soft_heap_limit(int);
1485
1486/*
1487** This routine makes sure that all thread-local storage has been
1488** deallocated for the current thread.
1489**
1490** This routine is not technically necessary.  All thread-local storage
1491** will be automatically deallocated once memory-management and
1492** shared-cache are disabled and the soft heap limit has been set
1493** to zero.  This routine is provided as a convenience for users who
1494** want to make absolutely sure they have not forgotten something
1495** prior to killing off a thread.
1496*/
1497void sqlite3_thread_cleanup(void);
1498
1499/*
1500** Return meta information about a specific column of a specific database
1501** table accessible using the connection handle passed as the first function
1502** argument.
1503**
1504** The column is identified by the second, third and fourth parameters to
1505** this function. The second parameter is either the name of the database
1506** (i.e. "main", "temp" or an attached database) containing the specified
1507** table or NULL. If it is NULL, then all attached databases are searched
1508** for the table using the same algorithm as the database engine uses to
1509** resolve unqualified table references.
1510**
1511** The third and fourth parameters to this function are the table and column
1512** name of the desired column, respectively. Neither of these parameters
1513** may be NULL.
1514**
1515** Meta information is returned by writing to the memory locations passed as
1516** the 5th and subsequent parameters to this function. Any of these
1517** arguments may be NULL, in which case the corresponding element of meta
1518** information is ommitted.
1519**
1520** Parameter     Output Type      Description
1521** -----------------------------------
1522**
1523**   5th         const char*      Data type
1524**   6th         const char*      Name of the default collation sequence
1525**   7th         int              True if the column has a NOT NULL constraint
1526**   8th         int              True if the column is part of the PRIMARY KEY
1527**   9th         int              True if the column is AUTOINCREMENT
1528**
1529**
1530** The memory pointed to by the character pointers returned for the
1531** declaration type and collation sequence is valid only until the next
1532** call to any sqlite API function.
1533**
1534** If the specified table is actually a view, then an error is returned.
1535**
1536** If the specified column is "rowid", "oid" or "_rowid_" and an
1537** INTEGER PRIMARY KEY column has been explicitly declared, then the output
1538** parameters are set for the explicitly declared column. If there is no
1539** explicitly declared IPK column, then the output parameters are set as
1540** follows:
1541**
1542**     data type: "INTEGER"
1543**     collation sequence: "BINARY"
1544**     not null: 0
1545**     primary key: 1
1546**     auto increment: 0
1547**
1548** This function may load one or more schemas from database files. If an
1549** error occurs during this process, or if the requested table or column
1550** cannot be found, an SQLITE error code is returned and an error message
1551** left in the database handle (to be retrieved using sqlite3_errmsg()).
1552**
1553** This API is only available if the library was compiled with the
1554** SQLITE_ENABLE_COLUMN_METADATA preprocessor symbol defined.
1555*/
1556int sqlite3_table_column_metadata(
1557  sqlite3 *db,                /* Connection handle */
1558  const char *zDbName,        /* Database name or NULL */
1559  const char *zTableName,     /* Table name */
1560  const char *zColumnName,    /* Column name */
1561  char const **pzDataType,    /* OUTPUT: Declared data type */
1562  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
1563  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
1564  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
1565  int *pAutoinc               /* OUTPUT: True if colums is auto-increment */
1566);
1567
1568/*
1569****** EXPERIMENTAL - subject to change without notice **************
1570**
1571** Attempt to load an SQLite extension library contained in the file
1572** zFile.  The entry point is zProc.  zProc may be 0 in which case the
1573** name of the entry point defaults to "sqlite3_extension_init".
1574**
1575** Return SQLITE_OK on success and SQLITE_ERROR if something goes wrong.
1576**
1577** If an error occurs and pzErrMsg is not 0, then fill *pzErrMsg with
1578** error message text.  The calling function should free this memory
1579** by calling sqlite3_free().
1580**
1581** Extension loading must be enabled using sqlite3_enable_load_extension()
1582** prior to calling this API or an error will be returned.
1583**
1584****** EXPERIMENTAL - subject to change without notice **************
1585*/
1586int sqlite3_load_extension(
1587  sqlite3 *db,          /* Load the extension into this database connection */
1588  const char *zFile,    /* Name of the shared library containing extension */
1589  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
1590  char **pzErrMsg       /* Put error message here if not 0 */
1591);
1592
1593/*
1594** So as not to open security holes in older applications that are
1595** unprepared to deal with extension load, and as a means of disabling
1596** extension loading while executing user-entered SQL, the following
1597** API is provided to turn the extension loading mechanism on and
1598** off.  It is off by default.  See ticket #1863.
1599**
1600** Call this routine with onoff==1 to turn extension loading on
1601** and call it with onoff==0 to turn it back off again.
1602*/
1603int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
1604
1605/*
1606****** EXPERIMENTAL - subject to change without notice **************
1607**
1608** Register an extension entry point that is automatically invoked
1609** whenever a new database connection is opened.
1610**
1611** This API can be invoked at program startup in order to register
1612** one or more statically linked extensions that will be available
1613** to all new database connections.
1614**
1615** Duplicate extensions are detected so calling this routine multiple
1616** times with the same extension is harmless.
1617**
1618** This routine stores a pointer to the extension in an array
1619** that is obtained from malloc().  If you run a memory leak
1620** checker on your program and it reports a leak because of this
1621** array, then invoke sqlite3_automatic_extension_reset() prior
1622** to shutdown to free the memory.
1623**
1624** Automatic extensions apply across all threads.
1625*/
1626int sqlite3_auto_extension(void *xEntryPoint);
1627
1628
1629/*
1630****** EXPERIMENTAL - subject to change without notice **************
1631**
1632** Disable all previously registered automatic extensions.  This
1633** routine undoes the effect of all prior sqlite3_automatic_extension()
1634** calls.
1635**
1636** This call disabled automatic extensions in all threads.
1637*/
1638void sqlite3_reset_auto_extension(void);
1639
1640
1641/*
1642****** EXPERIMENTAL - subject to change without notice **************
1643**
1644** The interface to the virtual-table mechanism is currently considered
1645** to be experimental.  The interface might change in incompatible ways.
1646** If this is a problem for you, do not use the interface at this time.
1647**
1648** When the virtual-table mechanism stablizes, we will declare the
1649** interface fixed, support it indefinitely, and remove this comment.
1650*/
1651
1652/*
1653** Structures used by the virtual table interface
1654*/
1655typedef struct sqlite3_vtab sqlite3_vtab;
1656typedef struct sqlite3_index_info sqlite3_index_info;
1657typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
1658typedef struct sqlite3_module sqlite3_module;
1659
1660/*
1661** A module is a class of virtual tables.  Each module is defined
1662** by an instance of the following structure.  This structure consists
1663** mostly of methods for the module.
1664*/
1665struct sqlite3_module {
1666  int iVersion;
1667  int (*xCreate)(sqlite3*, void *pAux,
1668               int argc, const char *const*argv,
1669               sqlite3_vtab **ppVTab, char**);
1670  int (*xConnect)(sqlite3*, void *pAux,
1671               int argc, const char *const*argv,
1672               sqlite3_vtab **ppVTab, char**);
1673  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
1674  int (*xDisconnect)(sqlite3_vtab *pVTab);
1675  int (*xDestroy)(sqlite3_vtab *pVTab);
1676  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
1677  int (*xClose)(sqlite3_vtab_cursor*);
1678  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
1679                int argc, sqlite3_value **argv);
1680  int (*xNext)(sqlite3_vtab_cursor*);
1681  int (*xEof)(sqlite3_vtab_cursor*);
1682  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
1683  int (*xRowid)(sqlite3_vtab_cursor*, sqlite_int64 *pRowid);
1684  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite_int64 *);
1685  int (*xBegin)(sqlite3_vtab *pVTab);
1686  int (*xSync)(sqlite3_vtab *pVTab);
1687  int (*xCommit)(sqlite3_vtab *pVTab);
1688  int (*xRollback)(sqlite3_vtab *pVTab);
1689  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
1690                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
1691                       void **ppArg);
1692};
1693
1694/*
1695** The sqlite3_index_info structure and its substructures is used to
1696** pass information into and receive the reply from the xBestIndex
1697** method of an sqlite3_module.  The fields under **Inputs** are the
1698** inputs to xBestIndex and are read-only.  xBestIndex inserts its
1699** results into the **Outputs** fields.
1700**
1701** The aConstraint[] array records WHERE clause constraints of the
1702** form:
1703**
1704**         column OP expr
1705**
1706** Where OP is =, <, <=, >, or >=.  The particular operator is stored
1707** in aConstraint[].op.  The index of the column is stored in
1708** aConstraint[].iColumn.  aConstraint[].usable is TRUE if the
1709** expr on the right-hand side can be evaluated (and thus the constraint
1710** is usable) and false if it cannot.
1711**
1712** The optimizer automatically inverts terms of the form "expr OP column"
1713** and makes other simplificatinos to the WHERE clause in an attempt to
1714** get as many WHERE clause terms into the form shown above as possible.
1715** The aConstraint[] array only reports WHERE clause terms in the correct
1716** form that refer to the particular virtual table being queried.
1717**
1718** Information about the ORDER BY clause is stored in aOrderBy[].
1719** Each term of aOrderBy records a column of the ORDER BY clause.
1720**
1721** The xBestIndex method must fill aConstraintUsage[] with information
1722** about what parameters to pass to xFilter.  If argvIndex>0 then
1723** the right-hand side of the corresponding aConstraint[] is evaluated
1724** and becomes the argvIndex-th entry in argv.  If aConstraintUsage[].omit
1725** is true, then the constraint is assumed to be fully handled by the
1726** virtual table and is not checked again by SQLite.
1727**
1728** The idxNum and idxPtr values are recorded and passed into xFilter.
1729** sqlite3_free() is used to free idxPtr if needToFreeIdxPtr is true.
1730**
1731** The orderByConsumed means that output from xFilter will occur in
1732** the correct order to satisfy the ORDER BY clause so that no separate
1733** sorting step is required.
1734**
1735** The estimatedCost value is an estimate of the cost of doing the
1736** particular lookup.  A full scan of a table with N entries should have
1737** a cost of N.  A binary search of a table of N entries should have a
1738** cost of approximately log(N).
1739*/
1740struct sqlite3_index_info {
1741  /* Inputs */
1742  const int nConstraint;     /* Number of entries in aConstraint */
1743  const struct sqlite3_index_constraint {
1744     int iColumn;              /* Column on left-hand side of constraint */
1745     unsigned char op;         /* Constraint operator */
1746     unsigned char usable;     /* True if this constraint is usable */
1747     int iTermOffset;          /* Used internally - xBestIndex should ignore */
1748  } *const aConstraint;      /* Table of WHERE clause constraints */
1749  const int nOrderBy;        /* Number of terms in the ORDER BY clause */
1750  const struct sqlite3_index_orderby {
1751     int iColumn;              /* Column number */
1752     unsigned char desc;       /* True for DESC.  False for ASC. */
1753  } *const aOrderBy;         /* The ORDER BY clause */
1754
1755  /* Outputs */
1756  struct sqlite3_index_constraint_usage {
1757    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
1758    unsigned char omit;      /* Do not code a test for this constraint */
1759  } *const aConstraintUsage;
1760  int idxNum;                /* Number used to identify the index */
1761  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
1762  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
1763  int orderByConsumed;       /* True if output is already ordered */
1764  double estimatedCost;      /* Estimated cost of using this index */
1765};
1766#define SQLITE_INDEX_CONSTRAINT_EQ    2
1767#define SQLITE_INDEX_CONSTRAINT_GT    4
1768#define SQLITE_INDEX_CONSTRAINT_LE    8
1769#define SQLITE_INDEX_CONSTRAINT_LT    16
1770#define SQLITE_INDEX_CONSTRAINT_GE    32
1771#define SQLITE_INDEX_CONSTRAINT_MATCH 64
1772
1773/*
1774** This routine is used to register a new module name with an SQLite
1775** connection.  Module names must be registered before creating new
1776** virtual tables on the module, or before using preexisting virtual
1777** tables of the module.
1778*/
1779int sqlite3_create_module(
1780  sqlite3 *db,               /* SQLite connection to register module with */
1781  const char *zName,         /* Name of the module */
1782  const sqlite3_module *,    /* Methods for the module */
1783  void *                     /* Client data for xCreate/xConnect */
1784);
1785
1786/*
1787** Every module implementation uses a subclass of the following structure
1788** to describe a particular instance of the module.  Each subclass will
1789** be taylored to the specific needs of the module implementation.   The
1790** purpose of this superclass is to define certain fields that are common
1791** to all module implementations.
1792**
1793** Virtual tables methods can set an error message by assigning a
1794** string obtained from sqlite3_mprintf() to zErrMsg.  The method should
1795** take care that any prior string is freed by a call to sqlite3_free()
1796** prior to assigning a new string to zErrMsg.  After the error message
1797** is delivered up to the client application, the string will be automatically
1798** freed by sqlite3_free() and the zErrMsg field will be zeroed.  Note
1799** that sqlite3_mprintf() and sqlite3_free() are used on the zErrMsg field
1800** since virtual tables are commonly implemented in loadable extensions which
1801** do not have access to sqlite3MPrintf() or sqlite3Free().
1802*/
1803struct sqlite3_vtab {
1804  const sqlite3_module *pModule;  /* The module for this virtual table */
1805  int nRef;                       /* Used internally */
1806  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
1807  /* Virtual table implementations will typically add additional fields */
1808};
1809
1810/* Every module implementation uses a subclass of the following structure
1811** to describe cursors that point into the virtual table and are used
1812** to loop through the virtual table.  Cursors are created using the
1813** xOpen method of the module.  Each module implementation will define
1814** the content of a cursor structure to suit its own needs.
1815**
1816** This superclass exists in order to define fields of the cursor that
1817** are common to all implementations.
1818*/
1819struct sqlite3_vtab_cursor {
1820  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
1821  /* Virtual table implementations will typically add additional fields */
1822};
1823
1824/*
1825** The xCreate and xConnect methods of a module use the following API
1826** to declare the format (the names and datatypes of the columns) of
1827** the virtual tables they implement.
1828*/
1829int sqlite3_declare_vtab(sqlite3*, const char *zCreateTable);
1830
1831/*
1832** Virtual tables can provide alternative implementations of functions
1833** using the xFindFunction method.  But global versions of those functions
1834** must exist in order to be overloaded.
1835**
1836** This API makes sure a global version of a function with a particular
1837** name and number of parameters exists.  If no such function exists
1838** before this API is called, a new function is created.  The implementation
1839** of the new function always causes an exception to be thrown.  So
1840** the new function is not good for anything by itself.  Its only
1841** purpose is to be a place-holder function that can be overloaded
1842** by virtual tables.
1843**
1844** This API should be considered part of the virtual table interface,
1845** which is experimental and subject to change.
1846*/
1847int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
1848
1849/*
1850** The interface to the virtual-table mechanism defined above (back up
1851** to a comment remarkably similar to this one) is currently considered
1852** to be experimental.  The interface might change in incompatible ways.
1853** If this is a problem for you, do not use the interface at this time.
1854**
1855** When the virtual-table mechanism stablizes, we will declare the
1856** interface fixed, support it indefinitely, and remove this comment.
1857**
1858****** EXPERIMENTAL - subject to change without notice **************
1859*/
1860
1861/*
1862** Undo the hack that converts floating point types to integer for
1863** builds on processors without floating point support.
1864*/
1865#ifdef SQLITE_OMIT_FLOATING_POINT
1866# undef double
1867#endif
1868
1869#ifdef __cplusplus
1870}  /* End of the 'extern "C"' block */
1871#endif
1872#endif
1873