xref: /sqlite-3.40.0/src/sqliteInt.h (revision c22bd47d)
175897234Sdrh /*
2b19a2bc6Sdrh ** 2001 September 15
375897234Sdrh **
4b19a2bc6Sdrh ** The author disclaims copyright to this source code.  In place of
5b19a2bc6Sdrh ** a legal notice, here is a blessing:
675897234Sdrh **
7b19a2bc6Sdrh **    May you do good and not evil.
8b19a2bc6Sdrh **    May you find forgiveness for yourself and forgive others.
9b19a2bc6Sdrh **    May you share freely, never taking more than you give.
1075897234Sdrh **
1175897234Sdrh *************************************************************************
1275897234Sdrh ** Internal interface definitions for SQLite.
1375897234Sdrh **
14*c22bd47dSdrh ** @(#) $Id: sqliteInt.h,v 1.107 2002/05/10 13:14:07 drh Exp $
1575897234Sdrh */
1675897234Sdrh #include "sqlite.h"
17beae3194Sdrh #include "hash.h"
1875897234Sdrh #include "vdbe.h"
1975897234Sdrh #include "parse.h"
20be0072d2Sdrh #include "btree.h"
2175897234Sdrh #include <stdio.h>
2275897234Sdrh #include <stdlib.h>
2375897234Sdrh #include <string.h>
2475897234Sdrh #include <assert.h>
2575897234Sdrh 
26967e8b73Sdrh /*
27a1b351afSdrh ** The maximum number of in-memory pages to use for the main database
28a1b351afSdrh ** table and for temporary tables.
29a1b351afSdrh */
30603240cfSdrh #define MAX_PAGES   2000
31603240cfSdrh #define TEMP_PAGES   500
32a1b351afSdrh 
33a1b351afSdrh /*
345a2c2c20Sdrh ** Integers of known sizes.  These typedefs might change for architectures
355a2c2c20Sdrh ** where the sizes very.  Preprocessor macros are available so that the
365a2c2c20Sdrh ** types can be conveniently redefined at compile-type.  Like this:
375a2c2c20Sdrh **
385a2c2c20Sdrh **         cc '-DUINTPTR_TYPE=long long int' ...
3941a2b48bSdrh */
405a2c2c20Sdrh #ifndef UINT32_TYPE
415a2c2c20Sdrh # define UINT32_TYPE unsigned int
425a2c2c20Sdrh #endif
435a2c2c20Sdrh #ifndef UINT16_TYPE
445a2c2c20Sdrh # define UINT16_TYPE unsigned short int
455a2c2c20Sdrh #endif
465a2c2c20Sdrh #ifndef UINT8_TYPE
475a2c2c20Sdrh # define UINT8_TYPE unsigned char
485a2c2c20Sdrh #endif
495a2c2c20Sdrh #ifndef INTPTR_TYPE
505a2c2c20Sdrh # define INTPTR_TYPE int
515a2c2c20Sdrh #endif
525a2c2c20Sdrh typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
535a2c2c20Sdrh typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
545a2c2c20Sdrh typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
555a2c2c20Sdrh typedef INTPTR_TYPE ptr;           /* Big enough to hold a pointer */
565a2c2c20Sdrh typedef unsigned INTPTR_TYPE uptr; /* Big enough to hold a pointer */
575a2c2c20Sdrh 
585a2c2c20Sdrh /*
595a2c2c20Sdrh ** This macro casts a pointer to an integer.  Useful for doing
605a2c2c20Sdrh ** pointer arithmetic.
615a2c2c20Sdrh */
625a2c2c20Sdrh #define Addr(X)  ((uptr)X)
6341a2b48bSdrh 
6441a2b48bSdrh /*
65872ff86fSdrh ** The maximum number of bytes of data that can be put into a single
6680ff32f5Sdrh ** row of a single table.  The upper bound on this limit is 16777215
6780ff32f5Sdrh ** bytes (or 16MB-1).  We have arbitrarily set the limit to just 1MB
6880ff32f5Sdrh ** here because the overflow page chain is inefficient for really big
6980ff32f5Sdrh ** records and we want to discourage people from thinking that
7080ff32f5Sdrh ** multi-megabyte records are OK.  If your needs are different, you can
7180ff32f5Sdrh ** change this define and recompile to increase or decrease the record
7280ff32f5Sdrh ** size.
73872ff86fSdrh */
7480ff32f5Sdrh #define MAX_BYTES_PER_ROW  1048576
75872ff86fSdrh 
76872ff86fSdrh /*
77967e8b73Sdrh ** If memory allocation problems are found, recompile with
78967e8b73Sdrh **
79967e8b73Sdrh **      -DMEMORY_DEBUG=1
80967e8b73Sdrh **
81967e8b73Sdrh ** to enable some sanity checking on malloc() and free().  To
82967e8b73Sdrh ** check for memory leaks, recompile with
83967e8b73Sdrh **
84967e8b73Sdrh **      -DMEMORY_DEBUG=2
85967e8b73Sdrh **
86967e8b73Sdrh ** and a line of text will be written to standard error for
87967e8b73Sdrh ** each malloc() and free().  This output can be analyzed
88967e8b73Sdrh ** by an AWK script to determine if there are any leaks.
89967e8b73Sdrh */
90dcc581ccSdrh #ifdef MEMORY_DEBUG
91dcc581ccSdrh # define sqliteMalloc(X)    sqliteMalloc_(X,__FILE__,__LINE__)
92dcc581ccSdrh # define sqliteFree(X)      sqliteFree_(X,__FILE__,__LINE__)
93dcc581ccSdrh # define sqliteRealloc(X,Y) sqliteRealloc_(X,Y,__FILE__,__LINE__)
946e142f54Sdrh # define sqliteStrDup(X)    sqliteStrDup_(X,__FILE__,__LINE__)
956e142f54Sdrh # define sqliteStrNDup(X,Y) sqliteStrNDup_(X,Y,__FILE__,__LINE__)
96c3c2fc9aSdrh   void sqliteStrRealloc(char**);
97c3c2fc9aSdrh #else
98c3c2fc9aSdrh # define sqliteStrRealloc(X)
99dcc581ccSdrh #endif
100dcc581ccSdrh 
10175897234Sdrh /*
102daffd0e5Sdrh ** This variable gets set if malloc() ever fails.  After it gets set,
103daffd0e5Sdrh ** the SQLite library shuts down permanently.
104daffd0e5Sdrh */
105daffd0e5Sdrh extern int sqlite_malloc_failed;
106daffd0e5Sdrh 
107daffd0e5Sdrh /*
1086e142f54Sdrh ** The following global variables are used for testing and debugging
1098c82b350Sdrh ** only.  They only work if MEMORY_DEBUG is defined.
1106e142f54Sdrh */
1116e142f54Sdrh #ifdef MEMORY_DEBUG
1128c82b350Sdrh extern int sqlite_nMalloc;       /* Number of sqliteMalloc() calls */
1138c82b350Sdrh extern int sqlite_nFree;         /* Number of sqliteFree() calls */
1148c82b350Sdrh extern int sqlite_iMallocFail;   /* Fail sqliteMalloc() after this many calls */
1156e142f54Sdrh #endif
1166e142f54Sdrh 
1176e142f54Sdrh /*
11875897234Sdrh ** Name of the master database table.  The master database table
11975897234Sdrh ** is a special table that holds the names and attributes of all
12075897234Sdrh ** user tables and indices.
12175897234Sdrh */
12275897234Sdrh #define MASTER_NAME   "sqlite_master"
12375897234Sdrh 
12475897234Sdrh /*
12575897234Sdrh ** A convenience macro that returns the number of elements in
12675897234Sdrh ** an array.
12775897234Sdrh */
12875897234Sdrh #define ArraySize(X)    (sizeof(X)/sizeof(X[0]))
12975897234Sdrh 
13075897234Sdrh /*
13175897234Sdrh ** Forward references to structures
13275897234Sdrh */
1337020f651Sdrh typedef struct Column Column;
13475897234Sdrh typedef struct Table Table;
13575897234Sdrh typedef struct Index Index;
13675897234Sdrh typedef struct Instruction Instruction;
13775897234Sdrh typedef struct Expr Expr;
13875897234Sdrh typedef struct ExprList ExprList;
13975897234Sdrh typedef struct Parse Parse;
14075897234Sdrh typedef struct Token Token;
14175897234Sdrh typedef struct IdList IdList;
14275897234Sdrh typedef struct WhereInfo WhereInfo;
1436b56344dSdrh typedef struct WhereLevel WhereLevel;
1449bb61fe7Sdrh typedef struct Select Select;
1452282792aSdrh typedef struct AggExpr AggExpr;
1460bce8354Sdrh typedef struct FuncDef FuncDef;
14775897234Sdrh 
14875897234Sdrh /*
14975897234Sdrh ** Each database is an instance of the following structure
15075897234Sdrh */
15175897234Sdrh struct sqlite {
1525e00f6c7Sdrh   Btree *pBe;                   /* The B*Tree backend */
153f57b3399Sdrh   Btree *pBeTemp;               /* Backend for session temporary tables */
1548c82b350Sdrh   int flags;                    /* Miscellanous flags. See below */
1552803757aSdrh   int file_format;              /* What file format version is this database? */
15650e5dadfSdrh   int schema_cookie;            /* Magic number that changes with the schema */
15750e5dadfSdrh   int next_cookie;              /* Value of schema_cookie after commit */
158cd61c281Sdrh   int cache_size;               /* Number of pages to use in the cache */
1592803757aSdrh   int nTable;                   /* Number of tables in the database */
1602dfbbcafSdrh   void *pBusyArg;               /* 1st Argument to the busy callback */
161353f57e0Sdrh   int (*xBusyCallback)(void *,const char*,int);  /* The busy callback */
162beae3194Sdrh   Hash tblHash;                 /* All tables indexed by name */
163beae3194Sdrh   Hash idxHash;                 /* All (named) indices indexed by name */
16474e24cd0Sdrh   Hash tblDrop;                 /* Uncommitted DROP TABLEs */
16574e24cd0Sdrh   Hash idxDrop;                 /* Uncommitted DROP INDEXs */
1660bce8354Sdrh   Hash aFunc;                   /* All functions that can be in SQL exprs */
167af9ff33aSdrh   int lastRowid;                /* ROWID of most recent insert */
1685cf8e8c7Sdrh   int priorNewRowid;            /* Last randomly generated ROWID */
1691c92853dSdrh   int onError;                  /* Default conflict algorithm */
170247be43dSdrh   int magic;                    /* Magic number for detect library misuse */
171c8d30ac1Sdrh   int nChange;                  /* Number of rows changed */
172c8d30ac1Sdrh   int recursionDepth;           /* Number of nested calls to sqlite_exec() */
17375897234Sdrh };
17475897234Sdrh 
17575897234Sdrh /*
176967e8b73Sdrh ** Possible values for the sqlite.flags.
17775897234Sdrh */
1784c504391Sdrh #define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
1794c504391Sdrh #define SQLITE_Initialized    0x00000002  /* True after initialization */
1804c504391Sdrh #define SQLITE_Interrupt      0x00000004  /* Cancel current operation */
181c4a3c779Sdrh #define SQLITE_InTrans        0x00000008  /* True if in a transaction */
1825e00f6c7Sdrh #define SQLITE_InternChanges  0x00000010  /* Uncommitted Hash table changes */
183382c0247Sdrh #define SQLITE_FullColNames   0x00000020  /* Show full column names on SELECT */
1841bee3d7bSdrh #define SQLITE_CountRows      0x00000040  /* Count rows changed by INSERT, */
1851bee3d7bSdrh                                           /*   DELETE, or UPDATE and return */
1861bee3d7bSdrh                                           /*   the count using a callback. */
1876a535340Sdrh #define SQLITE_NullCallback   0x00000080  /* Invoke the callback once if the */
1886a535340Sdrh                                           /*   result set is empty */
189c3a64ba0Sdrh #define SQLITE_ResultDetails  0x00000100  /* Details added to result set */
190417be79cSdrh #define SQLITE_UnresetViews   0x00000200  /* True if one or more views have */
191417be79cSdrh                                           /*   defined column names */
19258b9576bSdrh 
19358b9576bSdrh /*
194247be43dSdrh ** Possible values for the sqlite.magic field.
195247be43dSdrh ** The numbers are obtained at random and have no special meaning, other
196247be43dSdrh ** than being distinct from one another.
197247be43dSdrh */
198247be43dSdrh #define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */
199247be43dSdrh #define SQLITE_MAGIC_CLOSED   0x9f3c2d33  /* Database is closed */
200247be43dSdrh #define SQLITE_MAGIC_BUSY     0xf03b7906  /* Database currently in use */
201247be43dSdrh #define SQLITE_MAGIC_ERROR    0xb5357930  /* An SQLITE_MISUSE error occurred */
202247be43dSdrh 
203247be43dSdrh /*
2040bce8354Sdrh ** Each SQL function is defined by an instance of the following
2050bce8354Sdrh ** structure.  A pointer to this structure is stored in the sqlite.aFunc
2068e0a2f90Sdrh ** hash table.  When multiple functions have the same name, the hash table
2078e0a2f90Sdrh ** points to a linked list of these structures.
2082803757aSdrh */
2090bce8354Sdrh struct FuncDef {
2101350b030Sdrh   void (*xFunc)(sqlite_func*,int,const char**);   /* Regular function */
21156c0e926Sdrh   void (*xStep)(sqlite_func*,int,const char**);  /* Aggregate function step */
2121350b030Sdrh   void (*xFinalize)(sqlite_func*);           /* Aggregate function finializer */
2138e0a2f90Sdrh   int nArg;                                  /* Number of arguments */
2141350b030Sdrh   void *pUserData;                           /* User data parameter */
2150bce8354Sdrh   FuncDef *pNext;                            /* Next function with same name */
2168e0a2f90Sdrh };
2172803757aSdrh 
2182803757aSdrh /*
219967e8b73Sdrh ** information about each column of an SQL table is held in an instance
2207020f651Sdrh ** of this structure.
2217020f651Sdrh */
2227020f651Sdrh struct Column {
2237020f651Sdrh   char *zName;     /* Name of this column */
2247020f651Sdrh   char *zDflt;     /* Default value of this column */
225382c0247Sdrh   char *zType;     /* Data type for this column */
2264a32431cSdrh   u8 notNull;      /* True if there is a NOT NULL constraint */
2274a32431cSdrh   u8 isPrimKey;    /* True if this column is an INTEGER PRIMARY KEY */
2287020f651Sdrh };
2297020f651Sdrh 
2307020f651Sdrh /*
23122f70c32Sdrh ** Each SQL table is represented in memory by an instance of the
23222f70c32Sdrh ** following structure.
23322f70c32Sdrh **
23422f70c32Sdrh ** Expr.zName is the name of the table.  The case of the original
23522f70c32Sdrh ** CREATE TABLE statement is stored, but case is not significant for
23622f70c32Sdrh ** comparisons.
23722f70c32Sdrh **
23822f70c32Sdrh ** Expr.nCol is the number of columns in this table.  Expr.aCol is a
23922f70c32Sdrh ** pointer to an array of Column structures, one for each column.
24022f70c32Sdrh **
24122f70c32Sdrh ** If the table has an INTEGER PRIMARY KEY, then Expr.iPKey is the index of
24222f70c32Sdrh ** the column that is that key.   Otherwise Expr.iPKey is negative.  Note
24322f70c32Sdrh ** that the datatype of the PRIMARY KEY must be INTEGER for this field to
24422f70c32Sdrh ** be set.  An INTEGER PRIMARY KEY is used as the rowid for each row of
24522f70c32Sdrh ** the table.  If a table has no INTEGER PRIMARY KEY, then a random rowid
24622f70c32Sdrh ** is generated for each row of the table.  Expr.hasPrimKey is true if
24722f70c32Sdrh ** the table has any PRIMARY KEY, INTEGER or otherwise.
24822f70c32Sdrh **
24922f70c32Sdrh ** Expr.tnum is the page number for the root BTree page of the table in the
25022f70c32Sdrh ** database file.  If Expr.isTemp is true, then this page occurs in the
25122f70c32Sdrh ** auxiliary database file, not the main database file.  If Expr.isTransient
25222f70c32Sdrh ** is true, then the table is stored in a file that is automatically deleted
25322f70c32Sdrh ** when the VDBE cursor to the table is closed.  In this case Expr.tnum
25422f70c32Sdrh ** refers VDBE cursor number that holds the table open, not to the root
25522f70c32Sdrh ** page number.  Transient tables are used to hold the results of a
25622f70c32Sdrh ** sub-query that appears instead of a real table name in the FROM clause
25722f70c32Sdrh ** of a SELECT statement.
25875897234Sdrh */
25975897234Sdrh struct Table {
26075897234Sdrh   char *zName;     /* Name of the table */
26175897234Sdrh   int nCol;        /* Number of columns in this table */
2627020f651Sdrh   Column *aCol;    /* Information about each column */
263c8392586Sdrh   int iPKey;       /* If not less then 0, use aCol[iPKey] as the primary key */
264967e8b73Sdrh   Index *pIndex;   /* List of SQL indexes on this table. */
26522f70c32Sdrh   int tnum;        /* Root BTree node for this table (see note above) */
266a76b5dfcSdrh   Select *pSelect; /* NULL for tables.  Points to definition if a view. */
267717e6402Sdrh   u8 readOnly;     /* True if this table should not be written by the user */
268717e6402Sdrh   u8 isCommit;     /* True if creation of this table has been committed */
269f57b3399Sdrh   u8 isTemp;       /* True if stored in db->pBeTemp instead of db->pBe */
27022f70c32Sdrh   u8 isTransient;  /* True if automatically deleted when VDBE finishes */
2714a32431cSdrh   u8 hasPrimKey;   /* True if there exists a primary key */
2729cfcf5d4Sdrh   u8 keyConf;      /* What to do in case of uniqueness conflict on iPKey */
27375897234Sdrh };
27475897234Sdrh 
27575897234Sdrh /*
27622f70c32Sdrh ** SQLite supports 5 different ways to resolve a contraint
27722f70c32Sdrh ** error.  ROLLBACK processing means that a constraint violation
2781c92853dSdrh ** causes the operation in proces to fail and for the current transaction
2791c92853dSdrh ** to be rolled back.  ABORT processing means the operation in process
2801c92853dSdrh ** fails and any prior changes from that one operation are backed out,
2811c92853dSdrh ** but the transaction is not rolled back.  FAIL processing means that
2821c92853dSdrh ** the operation in progress stops and returns an error code.  But prior
2831c92853dSdrh ** changes due to the same operation are not backed out and no rollback
2841c92853dSdrh ** occurs.  IGNORE means that the particular row that caused the constraint
2851c92853dSdrh ** error is not inserted or updated.  Processing continues and no error
2861c92853dSdrh ** is returned.  REPLACE means that preexisting database rows that caused
2871c92853dSdrh ** a UNIQUE constraint violation are removed so that the new insert or
2881c92853dSdrh ** update can proceed.  Processing continues and no error is reported.
2891c92853dSdrh **
2901c92853dSdrh ** The following there symbolic values are used to record which type
2911c92853dSdrh ** of action to take.
2929cfcf5d4Sdrh */
2939cfcf5d4Sdrh #define OE_None     0   /* There is no constraint to check */
2941c92853dSdrh #define OE_Rollback 1   /* Fail the operation and rollback the transaction */
2951c92853dSdrh #define OE_Abort    2   /* Back out changes but do no rollback transaction */
2961c92853dSdrh #define OE_Fail     3   /* Stop the operation but leave all prior changes */
2971c92853dSdrh #define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */
2981c92853dSdrh #define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */
2999cfcf5d4Sdrh #define OE_Default  9   /* Do whatever the default action is */
3009cfcf5d4Sdrh 
3019cfcf5d4Sdrh /*
30266b89c8fSdrh ** Each SQL index is represented in memory by an
30375897234Sdrh ** instance of the following structure.
304967e8b73Sdrh **
305967e8b73Sdrh ** The columns of the table that are to be indexed are described
306967e8b73Sdrh ** by the aiColumn[] field of this structure.  For example, suppose
307967e8b73Sdrh ** we have the following table and index:
308967e8b73Sdrh **
309967e8b73Sdrh **     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
310967e8b73Sdrh **     CREATE INDEX Ex2 ON Ex1(c3,c1);
311967e8b73Sdrh **
312967e8b73Sdrh ** In the Table structure describing Ex1, nCol==3 because there are
313967e8b73Sdrh ** three columns in the table.  In the Index structure describing
314967e8b73Sdrh ** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
315967e8b73Sdrh ** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the
316967e8b73Sdrh ** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
317967e8b73Sdrh ** The second column to be indexed (c1) has an index of 0 in
318967e8b73Sdrh ** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
31975897234Sdrh */
32075897234Sdrh struct Index {
32175897234Sdrh   char *zName;     /* Name of this index */
322967e8b73Sdrh   int nColumn;     /* Number of columns in the table used by this index */
323967e8b73Sdrh   int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
324967e8b73Sdrh   Table *pTable;   /* The SQL table being indexed */
325be0072d2Sdrh   int tnum;        /* Page containing root of this index in database file */
3269cfcf5d4Sdrh   u8 isUnique;     /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
327717e6402Sdrh   u8 isCommit;     /* True if creation of this index has been committed */
32874e24cd0Sdrh   u8 isDropped;    /* True if a DROP INDEX has executed on this index */
3299cfcf5d4Sdrh   u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
33075897234Sdrh   Index *pNext;    /* The next index associated with the same table */
33175897234Sdrh };
33275897234Sdrh 
33375897234Sdrh /*
33475897234Sdrh ** Each token coming out of the lexer is an instance of
33575897234Sdrh ** this structure.
33675897234Sdrh */
33775897234Sdrh struct Token {
33880ff32f5Sdrh   const char *z;      /* Text of the token.  Not NULL-terminated! */
33975897234Sdrh   int n;              /* Number of characters in this token */
34075897234Sdrh };
34175897234Sdrh 
34275897234Sdrh /*
34375897234Sdrh ** Each node of an expression in the parse tree is an instance
34422f70c32Sdrh ** of this structure.
34522f70c32Sdrh **
34622f70c32Sdrh ** Expr.op is the opcode.  The integer parser token codes are reused
34722f70c32Sdrh ** as opcodes here.  For example, the parser defines TK_GE to be an integer
34822f70c32Sdrh ** code representing the ">=" operator.  This same integer code is reused
34922f70c32Sdrh ** to represent the greater-than-or-equal-to operator in the expression
35022f70c32Sdrh ** tree.
35122f70c32Sdrh **
35222f70c32Sdrh ** Expr.pRight and Expr.pLeft are subexpressions.  Expr.pList is a list
35322f70c32Sdrh ** of argument if the expression is a function.
35422f70c32Sdrh **
35522f70c32Sdrh ** Expr.token is the operator token for this node.  Expr.span is the complete
35622f70c32Sdrh ** subexpression represented by this node and all its decendents.  These
35722f70c32Sdrh ** fields are used for error reporting and for reconstructing the text of
35822f70c32Sdrh ** an expression to use as the column name in a SELECT statement.
35922f70c32Sdrh **
36022f70c32Sdrh ** An expression of the form ID or ID.ID refers to a column in a table.
36122f70c32Sdrh ** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
36222f70c32Sdrh ** the integer cursor number of a VDBE cursor pointing to that table and
36322f70c32Sdrh ** Expr.iColumn is the column number for the specific column.  If the
36422f70c32Sdrh ** expression is used as a result in an aggregate SELECT, then the
36522f70c32Sdrh ** value is also stored in the Expr.iAgg column in the aggregate so that
36622f70c32Sdrh ** it can be accessed after all aggregates are computed.
36722f70c32Sdrh **
36822f70c32Sdrh ** If the expression is a function, the Expr.iTable is an integer code
36922f70c32Sdrh ** representing which function.
37022f70c32Sdrh **
37122f70c32Sdrh ** The Expr.pSelect field points to a SELECT statement.  The SELECT might
37222f70c32Sdrh ** be the right operand of an IN operator.  Or, if a scalar SELECT appears
37322f70c32Sdrh ** in an expression the opcode is TK_SELECT and Expr.pSelect is the only
37422f70c32Sdrh ** operand.
37575897234Sdrh */
37675897234Sdrh struct Expr {
37775897234Sdrh   int op;                /* Operation performed by this node */
37875897234Sdrh   Expr *pLeft, *pRight;  /* Left and right subnodes */
37975897234Sdrh   ExprList *pList;       /* A list of expressions used as a function argument */
38075897234Sdrh   Token token;           /* An operand token */
381e1b6a5b8Sdrh   Token span;            /* Complete text of the expression */
382967e8b73Sdrh   int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
383967e8b73Sdrh                          ** iColumn-th field of the iTable-th table.  When
384967e8b73Sdrh                          ** op==TK_FUNCTION, iColumn holds the function id */
385967e8b73Sdrh   int iAgg;              /* When op==TK_COLUMN and pParse->useAgg==TRUE, pull
386967e8b73Sdrh                          ** result from the iAgg-th element of the aggregator */
38719a775c2Sdrh   Select *pSelect;       /* When the expression is a sub-select */
38875897234Sdrh };
38975897234Sdrh 
39075897234Sdrh /*
39175897234Sdrh ** A list of expressions.  Each expression may optionally have a
39275897234Sdrh ** name.  An expr/name combination can be used in several ways, such
39375897234Sdrh ** as the list of "expr AS ID" fields following a "SELECT" or in the
39475897234Sdrh ** list of "ID = expr" items in an UPDATE.  A list of expressions can
39575897234Sdrh ** also be used as the argument to a function, in which case the azName
39675897234Sdrh ** field is not used.
39775897234Sdrh */
39875897234Sdrh struct ExprList {
39975897234Sdrh   int nExpr;             /* Number of expressions on the list */
4006d4abfbeSdrh   struct ExprList_item {
40175897234Sdrh     Expr *pExpr;           /* The list of expressions */
40275897234Sdrh     char *zName;           /* Token associated with this expression */
403d8bc7086Sdrh     char sortOrder;        /* 1 for DESC or 0 for ASC */
404d8bc7086Sdrh     char isAgg;            /* True if this is an aggregate like count(*) */
405d8bc7086Sdrh     char done;             /* A flag to indicate when processing is finished */
40675897234Sdrh   } *a;                  /* One entry for each expression */
40775897234Sdrh };
40875897234Sdrh 
40975897234Sdrh /*
41075897234Sdrh ** A list of identifiers.
41175897234Sdrh */
41275897234Sdrh struct IdList {
41375897234Sdrh   int nId;         /* Number of identifiers on the list */
4146d4abfbeSdrh   struct IdList_item {
41575897234Sdrh     char *zName;      /* Text of the identifier. */
41675897234Sdrh     char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
417967e8b73Sdrh     int idx;          /* Index in some Table.aCol[] of a column named zName */
418daffd0e5Sdrh     Table *pTab;      /* An SQL table corresponding to zName */
419daffd0e5Sdrh     Select *pSelect;  /* A SELECT statement used in place of a table name */
42075897234Sdrh   } *a;            /* One entry for each identifier on the list */
42175897234Sdrh };
42275897234Sdrh 
42375897234Sdrh /*
4246b56344dSdrh ** For each nested loop in a WHERE clause implementation, the WhereInfo
4256b56344dSdrh ** structure contains a single instance of this structure.  This structure
4266b56344dSdrh ** is intended to be private the the where.c module and should not be
4276b56344dSdrh ** access or modified by other modules.
4286b56344dSdrh */
4296b56344dSdrh struct WhereLevel {
4306b56344dSdrh   int iMem;            /* Memory cell used by this level */
4316b56344dSdrh   Index *pIdx;         /* Index used */
4326b56344dSdrh   int iCur;            /* Cursor number used for this index */
433487ab3caSdrh   int score;           /* How well this indexed scored */
4346b56344dSdrh   int brk;             /* Jump here to break out of the loop */
4356b56344dSdrh   int cont;            /* Jump here to continue with the next loop cycle */
4366b56344dSdrh   int op, p1, p2;      /* Opcode used to terminate the loop */
4376b56344dSdrh };
4386b56344dSdrh 
4396b56344dSdrh /*
44075897234Sdrh ** The WHERE clause processing routine has two halves.  The
44175897234Sdrh ** first part does the start of the WHERE loop and the second
44275897234Sdrh ** half does the tail of the WHERE loop.  An instance of
44375897234Sdrh ** this structure is returned by the first half and passed
44475897234Sdrh ** into the second half to give some continuity.
44575897234Sdrh */
44675897234Sdrh struct WhereInfo {
44775897234Sdrh   Parse *pParse;
44819a775c2Sdrh   IdList *pTabList;    /* List of tables in the join */
44919a775c2Sdrh   int iContinue;       /* Jump here to continue with next record */
45019a775c2Sdrh   int iBreak;          /* Jump here to break out of the loop */
45119a775c2Sdrh   int base;            /* Index of first Open opcode */
4526b56344dSdrh   int nLevel;          /* Number of nested loop */
453832508b7Sdrh   int savedNTab;       /* Value of pParse->nTab before WhereBegin() */
454832508b7Sdrh   int peakNTab;        /* Value of pParse->nTab after WhereBegin() */
4556b56344dSdrh   WhereLevel a[1];     /* Information about each nest loop in the WHERE */
45675897234Sdrh };
45775897234Sdrh 
45875897234Sdrh /*
4599bb61fe7Sdrh ** An instance of the following structure contains all information
4609bb61fe7Sdrh ** needed to generate code for a single SELECT statement.
461a76b5dfcSdrh **
462a76b5dfcSdrh ** The zSelect field is used when the Select structure must be persistent.
463a76b5dfcSdrh ** Normally, the expression tree points to tokens in the original input
464a76b5dfcSdrh ** string that encodes the select.  But if the Select structure must live
465a76b5dfcSdrh ** longer than its input string (for example when it is used to describe
466a76b5dfcSdrh ** a VIEW) we have to make a copy of the input string so that the nodes
467a76b5dfcSdrh ** of the expression tree will have something to point to.  zSelect is used
468a76b5dfcSdrh ** to hold that copy.
4699bb61fe7Sdrh */
4709bb61fe7Sdrh struct Select {
4719bb61fe7Sdrh   int isDistinct;        /* True if the DISTINCT keyword is present */
4729bb61fe7Sdrh   ExprList *pEList;      /* The fields of the result */
4739bb61fe7Sdrh   IdList *pSrc;          /* The FROM clause */
4749bb61fe7Sdrh   Expr *pWhere;          /* The WHERE clause */
4759bb61fe7Sdrh   ExprList *pGroupBy;    /* The GROUP BY clause */
4769bb61fe7Sdrh   Expr *pHaving;         /* The HAVING clause */
4779bb61fe7Sdrh   ExprList *pOrderBy;    /* The ORDER BY clause */
47882c3d636Sdrh   int op;                /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
479967e8b73Sdrh   Select *pPrior;        /* Prior select in a compound select statement */
4809bbca4c1Sdrh   int nLimit, nOffset;   /* LIMIT and OFFSET values.  -1 means not used */
481a76b5dfcSdrh   char *zSelect;         /* Complete text of the SELECT command */
482832508b7Sdrh   int base;              /* Index of VDBE cursor for left-most FROM table */
4839bb61fe7Sdrh };
4849bb61fe7Sdrh 
4859bb61fe7Sdrh /*
486fef5208cSdrh ** The results of a select can be distributed in several ways.
487fef5208cSdrh */
488fef5208cSdrh #define SRT_Callback     1  /* Invoke a callback with each row of result */
489fef5208cSdrh #define SRT_Mem          2  /* Store result in a memory cell */
49082c3d636Sdrh #define SRT_Set          3  /* Store result as unique keys in a table */
49182c3d636Sdrh #define SRT_Union        5  /* Store result as keys in a table */
49282c3d636Sdrh #define SRT_Except       6  /* Remove result from a UNION table */
4935974a30fSdrh #define SRT_Table        7  /* Store result as data with a unique key */
4942d0794e3Sdrh #define SRT_TempTable    8  /* Store result in a trasient table */
495fef5208cSdrh 
496fef5208cSdrh /*
4972282792aSdrh ** When a SELECT uses aggregate functions (like "count(*)" or "avg(f1)")
4982282792aSdrh ** we have to do some additional analysis of expressions.  An instance
4992282792aSdrh ** of the following structure holds information about a single subexpression
5002282792aSdrh ** somewhere in the SELECT statement.  An array of these structures holds
5012282792aSdrh ** all the information we need to generate code for aggregate
5022282792aSdrh ** expressions.
5032282792aSdrh **
5042282792aSdrh ** Note that when analyzing a SELECT containing aggregates, both
5052282792aSdrh ** non-aggregate field variables and aggregate functions are stored
5062282792aSdrh ** in the AggExpr array of the Parser structure.
5072282792aSdrh **
5082282792aSdrh ** The pExpr field points to an expression that is part of either the
5092282792aSdrh ** field list, the GROUP BY clause, the HAVING clause or the ORDER BY
5102282792aSdrh ** clause.  The expression will be freed when those clauses are cleaned
5112282792aSdrh ** up.  Do not try to delete the expression attached to AggExpr.pExpr.
5122282792aSdrh **
5132282792aSdrh ** If AggExpr.pExpr==0, that means the expression is "count(*)".
5142282792aSdrh */
5152282792aSdrh struct AggExpr {
5162282792aSdrh   int isAgg;        /* if TRUE contains an aggregate function */
5172282792aSdrh   Expr *pExpr;      /* The expression */
5180bce8354Sdrh   FuncDef *pFunc;   /* Information about the aggregate function */
5192282792aSdrh };
5202282792aSdrh 
5212282792aSdrh /*
522f57b3399Sdrh ** An SQL parser context.  A copy of this structure is passed through
523f57b3399Sdrh ** the parser and down into all the parser action routine in order to
524f57b3399Sdrh ** carry around information that is global to the entire parse.
52575897234Sdrh */
52675897234Sdrh struct Parse {
52775897234Sdrh   sqlite *db;          /* The main database structure */
5285e00f6c7Sdrh   Btree *pBe;          /* The database backend */
5294c504391Sdrh   int rc;              /* Return code from execution */
53075897234Sdrh   sqlite_callback xCallback;  /* The callback function */
53175897234Sdrh   void *pArg;          /* First argument to the callback function */
53275897234Sdrh   char *zErrMsg;       /* An error message */
53375897234Sdrh   Token sErrToken;     /* The token at which the error occurred */
53475897234Sdrh   Token sFirstToken;   /* The first token parsed */
53575897234Sdrh   Token sLastToken;    /* The last token parsed */
53675897234Sdrh   Table *pNewTable;    /* A table being constructed by CREATE TABLE */
53775897234Sdrh   Vdbe *pVdbe;         /* An engine for executing database bytecode */
538d8bc7086Sdrh   int colNamesSet;     /* TRUE after OP_ColumnCount has been issued to pVdbe */
53975897234Sdrh   int explain;         /* True if the EXPLAIN flag is found on the query */
54075897234Sdrh   int initFlag;        /* True if reparsing CREATE TABLEs */
541f57b3399Sdrh   int nameClash;       /* A permanent table name clashes with temp table name */
542d78eeee1Sdrh   int newTnum;         /* Table number to use when reparsing CREATE TABLEs */
54375897234Sdrh   int nErr;            /* Number of errors seen */
544832508b7Sdrh   int nTab;            /* Number of previously allocated VDBE cursors */
54519a775c2Sdrh   int nMem;            /* Number of memory cells used so far */
546fef5208cSdrh   int nSet;            /* Number of sets used so far */
5472282792aSdrh   int nAgg;            /* Number of aggregate expressions */
5482282792aSdrh   AggExpr *aAgg;       /* An array of aggregate expressions */
5492282792aSdrh   int useAgg;          /* If true, extract field values from the aggregator
5502282792aSdrh                        ** while generating expressions.  Normally false */
55150e5dadfSdrh   int schemaVerified;  /* True if an OP_VerifySchema has been coded someplace
55250e5dadfSdrh                        ** other than after an OP_Transaction */
55375897234Sdrh };
55475897234Sdrh 
55575897234Sdrh /*
55675897234Sdrh ** Internal function prototypes
55775897234Sdrh */
55875897234Sdrh int sqliteStrICmp(const char *, const char *);
55975897234Sdrh int sqliteStrNICmp(const char *, const char *, int);
56075897234Sdrh int sqliteHashNoCase(const char *, int);
56175897234Sdrh int sqliteCompare(const char *, const char *);
56275897234Sdrh int sqliteSortCompare(const char *, const char *);
5639bbca4c1Sdrh void sqliteRealToSortable(double r, char *);
564dcc581ccSdrh #ifdef MEMORY_DEBUG
565dcc581ccSdrh   void *sqliteMalloc_(int,char*,int);
566dcc581ccSdrh   void sqliteFree_(void*,char*,int);
567dcc581ccSdrh   void *sqliteRealloc_(void*,int,char*,int);
5686e142f54Sdrh   char *sqliteStrDup_(const char*,char*,int);
5696e142f54Sdrh   char *sqliteStrNDup_(const char*, int,char*,int);
570dcc581ccSdrh #else
57175897234Sdrh   void *sqliteMalloc(int);
57275897234Sdrh   void sqliteFree(void*);
57375897234Sdrh   void *sqliteRealloc(void*,int);
5746e142f54Sdrh   char *sqliteStrDup(const char*);
5756e142f54Sdrh   char *sqliteStrNDup(const char*, int);
576dcc581ccSdrh #endif
57775897234Sdrh void sqliteSetString(char **, const char *, ...);
57875897234Sdrh void sqliteSetNString(char **, ...);
579982cef7eSdrh void sqliteDequote(char*);
58017f71934Sdrh int sqliteKeywordCode(const char*, int);
58180ff32f5Sdrh int sqliteRunParser(Parse*, const char*, char **);
58275897234Sdrh void sqliteExec(Parse*);
58375897234Sdrh Expr *sqliteExpr(int, Expr*, Expr*, Token*);
584e1b6a5b8Sdrh void sqliteExprSpan(Expr*,Token*,Token*);
58575897234Sdrh Expr *sqliteExprFunction(ExprList*, Token*);
58675897234Sdrh void sqliteExprDelete(Expr*);
58775897234Sdrh ExprList *sqliteExprListAppend(ExprList*,Expr*,Token*);
58875897234Sdrh void sqliteExprListDelete(ExprList*);
589f57b14a6Sdrh void sqlitePragma(Parse*,Token*,Token*,int);
5905e00f6c7Sdrh void sqliteCommitInternalChanges(sqlite*);
5915e00f6c7Sdrh void sqliteRollbackInternalChanges(sqlite*);
592969fa7c1Sdrh Table *sqliteResultSetOfSelect(Parse*,char*,Select*);
593f57b3399Sdrh void sqliteStartTable(Parse*,Token*,Token*,int);
59475897234Sdrh void sqliteAddColumn(Parse*,Token*);
5959cfcf5d4Sdrh void sqliteAddNotNull(Parse*, int);
5969cfcf5d4Sdrh void sqliteAddPrimaryKey(Parse*, IdList*, int);
597382c0247Sdrh void sqliteAddColumnType(Parse*,Token*,Token*);
5987020f651Sdrh void sqliteAddDefaultValue(Parse*,Token*,int);
599969fa7c1Sdrh void sqliteEndTable(Parse*,Token*,Select*);
600a76b5dfcSdrh void sqliteCreateView(Parse*,Token*,Token*,Select*);
601417be79cSdrh int sqliteViewGetColumnNames(Parse*,Table*);
602417be79cSdrh void sqliteViewResetAll(sqlite*);
6034ff6dfa7Sdrh void sqliteDropTable(Parse*, Token*, int);
60475897234Sdrh void sqliteDeleteTable(sqlite*, Table*);
6059cfcf5d4Sdrh void sqliteInsert(Parse*, Token*, ExprList*, Select*, IdList*, int);
60675897234Sdrh IdList *sqliteIdListAppend(IdList*, Token*);
60775897234Sdrh void sqliteIdListAddAlias(IdList*, Token*);
60875897234Sdrh void sqliteIdListDelete(IdList*);
609717e6402Sdrh void sqliteCreateIndex(Parse*, Token*, Token*, IdList*, int, Token*, Token*);
61075897234Sdrh void sqliteDropIndex(Parse*, Token*);
6111b2e0329Sdrh int sqliteSelect(Parse*, Select*, int, int, Select*, int, int*);
6129bbca4c1Sdrh Select *sqliteSelectNew(ExprList*,IdList*,Expr*,ExprList*,Expr*,ExprList*,
6139bbca4c1Sdrh                         int,int,int);
6149bb61fe7Sdrh void sqliteSelectDelete(Select*);
615ff78bd2fSdrh void sqliteSelectUnbind(Select*);
616a76b5dfcSdrh Table *sqliteTableNameToTable(Parse*, const char*);
617a76b5dfcSdrh IdList *sqliteTableTokenToIdList(Parse*, Token*);
61875897234Sdrh void sqliteDeleteFrom(Parse*, Token*, Expr*);
6199cfcf5d4Sdrh void sqliteUpdate(Parse*, Token*, ExprList*, Expr*, int);
620832508b7Sdrh WhereInfo *sqliteWhereBegin(Parse*, int, IdList*, Expr*, int);
62175897234Sdrh void sqliteWhereEnd(WhereInfo*);
62275897234Sdrh void sqliteExprCode(Parse*, Expr*);
62375897234Sdrh void sqliteExprIfTrue(Parse*, Expr*, int);
62475897234Sdrh void sqliteExprIfFalse(Parse*, Expr*, int);
625a76b5dfcSdrh Table *sqliteFindTable(sqlite*,const char*);
626a76b5dfcSdrh Index *sqliteFindIndex(sqlite*,const char*);
6276d4abfbeSdrh void sqliteUnlinkAndDeleteIndex(sqlite*,Index*);
628b419a926Sdrh void sqliteCopy(Parse*, Token*, Token*, Token*, int);
629dce2cbe6Sdrh void sqliteVacuum(Parse*, Token*);
630e17a7e33Sdrh int sqliteGlobCompare(const unsigned char*,const unsigned char*);
631dce2cbe6Sdrh int sqliteLikeCompare(const unsigned char*,const unsigned char*);
632cce7d176Sdrh char *sqliteTableNameFromToken(Token*);
633cce7d176Sdrh int sqliteExprCheck(Parse*, Expr*, int, int*);
634d8bc7086Sdrh int sqliteExprCompare(Expr*, Expr*);
635cce7d176Sdrh int sqliteFuncId(Token*);
636832508b7Sdrh int sqliteExprResolveIds(Parse*, int, IdList*, ExprList*, Expr*);
6372282792aSdrh int sqliteExprAnalyzeAggregates(Parse*, Expr*);
638d8bc7086Sdrh Vdbe *sqliteGetVdbe(Parse*);
639b8ca307eSdrh int sqliteRandomByte(void);
640b8ca307eSdrh int sqliteRandomInteger(void);
6411c92853dSdrh void sqliteBeginTransaction(Parse*, int);
642c4a3c779Sdrh void sqliteCommitTransaction(Parse*);
643c4a3c779Sdrh void sqliteRollbackTransaction(Parse*);
644d1bf3512Sdrh char *sqlite_mprintf(const char *, ...);
6459208643dSdrh int sqliteExprIsConstant(Expr*);
646c8d30ac1Sdrh void sqliteGenerateRowDelete(Vdbe*, Table*, int, int);
6470ca3e24bSdrh void sqliteGenerateRowIndexDelete(Vdbe*, Table*, int, char*);
6480ca3e24bSdrh void sqliteGenerateConstraintChecks(Parse*,Table*,int,char*,int,int,int,int);
649b419a926Sdrh void sqliteCompleteInsertion(Parse*, Table*, int, char*, int, int);
6501c92853dSdrh void sqliteBeginWriteOperation(Parse*);
651663fc63aSdrh void sqliteBeginMultiWriteOperation(Parse*);
6521c92853dSdrh void sqliteEndWriteOperation(Parse*);
653a76b5dfcSdrh void sqliteExprMoveStrings(Expr*, int);
654a76b5dfcSdrh void sqliteExprListMoveStrings(ExprList*, int);
655a76b5dfcSdrh void sqliteSelectMoveStrings(Select*, int);
656ff78bd2fSdrh Expr *sqliteExprDup(Expr*);
657ff78bd2fSdrh ExprList *sqliteExprListDup(ExprList*);
658ff78bd2fSdrh IdList *sqliteIdListDup(IdList*);
659ff78bd2fSdrh Select *sqliteSelectDup(Select*);
6600bce8354Sdrh FuncDef *sqliteFindFunction(sqlite*,const char*,int,int,int);
661dc04c583Sdrh void sqliteRegisterBuildinFunctions(sqlite*);
662247be43dSdrh int sqliteSafetyOn(sqlite*);
663247be43dSdrh int sqliteSafetyOff(sqlite*);
664*c22bd47dSdrh int sqliteSafetyCheck(sqlite*);
665