xref: /sqlite-3.40.0/src/sqliteInt.h (revision cd61c281)
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*cd61c281Sdrh ** @(#) $Id: sqliteInt.h,v 1.103 2002/03/06 22:01:36 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 */
158*cd61c281Sdrh   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 */
17075897234Sdrh };
17175897234Sdrh 
17275897234Sdrh /*
173967e8b73Sdrh ** Possible values for the sqlite.flags.
17475897234Sdrh */
1754c504391Sdrh #define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
1764c504391Sdrh #define SQLITE_Initialized    0x00000002  /* True after initialization */
1774c504391Sdrh #define SQLITE_Interrupt      0x00000004  /* Cancel current operation */
178c4a3c779Sdrh #define SQLITE_InTrans        0x00000008  /* True if in a transaction */
1795e00f6c7Sdrh #define SQLITE_InternChanges  0x00000010  /* Uncommitted Hash table changes */
180382c0247Sdrh #define SQLITE_FullColNames   0x00000020  /* Show full column names on SELECT */
1811bee3d7bSdrh #define SQLITE_CountRows      0x00000040  /* Count rows changed by INSERT, */
1821bee3d7bSdrh                                           /*   DELETE, or UPDATE and return */
1831bee3d7bSdrh                                           /*   the count using a callback. */
1846a535340Sdrh #define SQLITE_NullCallback   0x00000080  /* Invoke the callback once if the */
1856a535340Sdrh                                           /*   result set is empty */
186c3a64ba0Sdrh #define SQLITE_ResultDetails  0x00000100  /* Details added to result set */
187417be79cSdrh #define SQLITE_UnresetViews   0x00000200  /* True if one or more views have */
188417be79cSdrh                                           /*   defined column names */
18958b9576bSdrh 
19058b9576bSdrh /*
1910bce8354Sdrh ** Each SQL function is defined by an instance of the following
1920bce8354Sdrh ** structure.  A pointer to this structure is stored in the sqlite.aFunc
1938e0a2f90Sdrh ** hash table.  When multiple functions have the same name, the hash table
1948e0a2f90Sdrh ** points to a linked list of these structures.
1952803757aSdrh */
1960bce8354Sdrh struct FuncDef {
1971350b030Sdrh   void (*xFunc)(sqlite_func*,int,const char**);   /* Regular function */
1981350b030Sdrh   void *(*xStep)(sqlite_func*,int,const char**);  /* Aggregate function step */
1991350b030Sdrh   void (*xFinalize)(sqlite_func*);           /* Aggregate function finializer */
2008e0a2f90Sdrh   int nArg;                                  /* Number of arguments */
2011350b030Sdrh   void *pUserData;                           /* User data parameter */
2020bce8354Sdrh   FuncDef *pNext;                            /* Next function with same name */
2038e0a2f90Sdrh };
2042803757aSdrh 
2052803757aSdrh /*
206967e8b73Sdrh ** information about each column of an SQL table is held in an instance
2077020f651Sdrh ** of this structure.
2087020f651Sdrh */
2097020f651Sdrh struct Column {
2107020f651Sdrh   char *zName;     /* Name of this column */
2117020f651Sdrh   char *zDflt;     /* Default value of this column */
212382c0247Sdrh   char *zType;     /* Data type for this column */
2134a32431cSdrh   u8 notNull;      /* True if there is a NOT NULL constraint */
2144a32431cSdrh   u8 isPrimKey;    /* True if this column is an INTEGER PRIMARY KEY */
2157020f651Sdrh };
2167020f651Sdrh 
2177020f651Sdrh /*
21822f70c32Sdrh ** Each SQL table is represented in memory by an instance of the
21922f70c32Sdrh ** following structure.
22022f70c32Sdrh **
22122f70c32Sdrh ** Expr.zName is the name of the table.  The case of the original
22222f70c32Sdrh ** CREATE TABLE statement is stored, but case is not significant for
22322f70c32Sdrh ** comparisons.
22422f70c32Sdrh **
22522f70c32Sdrh ** Expr.nCol is the number of columns in this table.  Expr.aCol is a
22622f70c32Sdrh ** pointer to an array of Column structures, one for each column.
22722f70c32Sdrh **
22822f70c32Sdrh ** If the table has an INTEGER PRIMARY KEY, then Expr.iPKey is the index of
22922f70c32Sdrh ** the column that is that key.   Otherwise Expr.iPKey is negative.  Note
23022f70c32Sdrh ** that the datatype of the PRIMARY KEY must be INTEGER for this field to
23122f70c32Sdrh ** be set.  An INTEGER PRIMARY KEY is used as the rowid for each row of
23222f70c32Sdrh ** the table.  If a table has no INTEGER PRIMARY KEY, then a random rowid
23322f70c32Sdrh ** is generated for each row of the table.  Expr.hasPrimKey is true if
23422f70c32Sdrh ** the table has any PRIMARY KEY, INTEGER or otherwise.
23522f70c32Sdrh **
23622f70c32Sdrh ** Expr.tnum is the page number for the root BTree page of the table in the
23722f70c32Sdrh ** database file.  If Expr.isTemp is true, then this page occurs in the
23822f70c32Sdrh ** auxiliary database file, not the main database file.  If Expr.isTransient
23922f70c32Sdrh ** is true, then the table is stored in a file that is automatically deleted
24022f70c32Sdrh ** when the VDBE cursor to the table is closed.  In this case Expr.tnum
24122f70c32Sdrh ** refers VDBE cursor number that holds the table open, not to the root
24222f70c32Sdrh ** page number.  Transient tables are used to hold the results of a
24322f70c32Sdrh ** sub-query that appears instead of a real table name in the FROM clause
24422f70c32Sdrh ** of a SELECT statement.
24575897234Sdrh */
24675897234Sdrh struct Table {
24775897234Sdrh   char *zName;     /* Name of the table */
24875897234Sdrh   int nCol;        /* Number of columns in this table */
2497020f651Sdrh   Column *aCol;    /* Information about each column */
250c8392586Sdrh   int iPKey;       /* If not less then 0, use aCol[iPKey] as the primary key */
251967e8b73Sdrh   Index *pIndex;   /* List of SQL indexes on this table. */
25222f70c32Sdrh   int tnum;        /* Root BTree node for this table (see note above) */
253a76b5dfcSdrh   Select *pSelect; /* NULL for tables.  Points to definition if a view. */
254717e6402Sdrh   u8 readOnly;     /* True if this table should not be written by the user */
255717e6402Sdrh   u8 isCommit;     /* True if creation of this table has been committed */
256f57b3399Sdrh   u8 isTemp;       /* True if stored in db->pBeTemp instead of db->pBe */
25722f70c32Sdrh   u8 isTransient;  /* True if automatically deleted when VDBE finishes */
2584a32431cSdrh   u8 hasPrimKey;   /* True if there exists a primary key */
2599cfcf5d4Sdrh   u8 keyConf;      /* What to do in case of uniqueness conflict on iPKey */
26075897234Sdrh };
26175897234Sdrh 
26275897234Sdrh /*
26322f70c32Sdrh ** SQLite supports 5 different ways to resolve a contraint
26422f70c32Sdrh ** error.  ROLLBACK processing means that a constraint violation
2651c92853dSdrh ** causes the operation in proces to fail and for the current transaction
2661c92853dSdrh ** to be rolled back.  ABORT processing means the operation in process
2671c92853dSdrh ** fails and any prior changes from that one operation are backed out,
2681c92853dSdrh ** but the transaction is not rolled back.  FAIL processing means that
2691c92853dSdrh ** the operation in progress stops and returns an error code.  But prior
2701c92853dSdrh ** changes due to the same operation are not backed out and no rollback
2711c92853dSdrh ** occurs.  IGNORE means that the particular row that caused the constraint
2721c92853dSdrh ** error is not inserted or updated.  Processing continues and no error
2731c92853dSdrh ** is returned.  REPLACE means that preexisting database rows that caused
2741c92853dSdrh ** a UNIQUE constraint violation are removed so that the new insert or
2751c92853dSdrh ** update can proceed.  Processing continues and no error is reported.
2761c92853dSdrh **
2771c92853dSdrh ** The following there symbolic values are used to record which type
2781c92853dSdrh ** of action to take.
2799cfcf5d4Sdrh */
2809cfcf5d4Sdrh #define OE_None     0   /* There is no constraint to check */
2811c92853dSdrh #define OE_Rollback 1   /* Fail the operation and rollback the transaction */
2821c92853dSdrh #define OE_Abort    2   /* Back out changes but do no rollback transaction */
2831c92853dSdrh #define OE_Fail     3   /* Stop the operation but leave all prior changes */
2841c92853dSdrh #define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */
2851c92853dSdrh #define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */
2869cfcf5d4Sdrh #define OE_Default  9   /* Do whatever the default action is */
2879cfcf5d4Sdrh 
2889cfcf5d4Sdrh /*
28966b89c8fSdrh ** Each SQL index is represented in memory by an
29075897234Sdrh ** instance of the following structure.
291967e8b73Sdrh **
292967e8b73Sdrh ** The columns of the table that are to be indexed are described
293967e8b73Sdrh ** by the aiColumn[] field of this structure.  For example, suppose
294967e8b73Sdrh ** we have the following table and index:
295967e8b73Sdrh **
296967e8b73Sdrh **     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
297967e8b73Sdrh **     CREATE INDEX Ex2 ON Ex1(c3,c1);
298967e8b73Sdrh **
299967e8b73Sdrh ** In the Table structure describing Ex1, nCol==3 because there are
300967e8b73Sdrh ** three columns in the table.  In the Index structure describing
301967e8b73Sdrh ** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
302967e8b73Sdrh ** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the
303967e8b73Sdrh ** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
304967e8b73Sdrh ** The second column to be indexed (c1) has an index of 0 in
305967e8b73Sdrh ** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
30675897234Sdrh */
30775897234Sdrh struct Index {
30875897234Sdrh   char *zName;     /* Name of this index */
309967e8b73Sdrh   int nColumn;     /* Number of columns in the table used by this index */
310967e8b73Sdrh   int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
311967e8b73Sdrh   Table *pTable;   /* The SQL table being indexed */
312be0072d2Sdrh   int tnum;        /* Page containing root of this index in database file */
3139cfcf5d4Sdrh   u8 isUnique;     /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
314717e6402Sdrh   u8 isCommit;     /* True if creation of this index has been committed */
31574e24cd0Sdrh   u8 isDropped;    /* True if a DROP INDEX has executed on this index */
3169cfcf5d4Sdrh   u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
31775897234Sdrh   Index *pNext;    /* The next index associated with the same table */
31875897234Sdrh };
31975897234Sdrh 
32075897234Sdrh /*
32175897234Sdrh ** Each token coming out of the lexer is an instance of
32275897234Sdrh ** this structure.
32375897234Sdrh */
32475897234Sdrh struct Token {
32580ff32f5Sdrh   const char *z;      /* Text of the token.  Not NULL-terminated! */
32675897234Sdrh   int n;              /* Number of characters in this token */
32775897234Sdrh };
32875897234Sdrh 
32975897234Sdrh /*
33075897234Sdrh ** Each node of an expression in the parse tree is an instance
33122f70c32Sdrh ** of this structure.
33222f70c32Sdrh **
33322f70c32Sdrh ** Expr.op is the opcode.  The integer parser token codes are reused
33422f70c32Sdrh ** as opcodes here.  For example, the parser defines TK_GE to be an integer
33522f70c32Sdrh ** code representing the ">=" operator.  This same integer code is reused
33622f70c32Sdrh ** to represent the greater-than-or-equal-to operator in the expression
33722f70c32Sdrh ** tree.
33822f70c32Sdrh **
33922f70c32Sdrh ** Expr.pRight and Expr.pLeft are subexpressions.  Expr.pList is a list
34022f70c32Sdrh ** of argument if the expression is a function.
34122f70c32Sdrh **
34222f70c32Sdrh ** Expr.token is the operator token for this node.  Expr.span is the complete
34322f70c32Sdrh ** subexpression represented by this node and all its decendents.  These
34422f70c32Sdrh ** fields are used for error reporting and for reconstructing the text of
34522f70c32Sdrh ** an expression to use as the column name in a SELECT statement.
34622f70c32Sdrh **
34722f70c32Sdrh ** An expression of the form ID or ID.ID refers to a column in a table.
34822f70c32Sdrh ** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
34922f70c32Sdrh ** the integer cursor number of a VDBE cursor pointing to that table and
35022f70c32Sdrh ** Expr.iColumn is the column number for the specific column.  If the
35122f70c32Sdrh ** expression is used as a result in an aggregate SELECT, then the
35222f70c32Sdrh ** value is also stored in the Expr.iAgg column in the aggregate so that
35322f70c32Sdrh ** it can be accessed after all aggregates are computed.
35422f70c32Sdrh **
35522f70c32Sdrh ** If the expression is a function, the Expr.iTable is an integer code
35622f70c32Sdrh ** representing which function.
35722f70c32Sdrh **
35822f70c32Sdrh ** The Expr.pSelect field points to a SELECT statement.  The SELECT might
35922f70c32Sdrh ** be the right operand of an IN operator.  Or, if a scalar SELECT appears
36022f70c32Sdrh ** in an expression the opcode is TK_SELECT and Expr.pSelect is the only
36122f70c32Sdrh ** operand.
36275897234Sdrh */
36375897234Sdrh struct Expr {
36475897234Sdrh   int op;                /* Operation performed by this node */
36575897234Sdrh   Expr *pLeft, *pRight;  /* Left and right subnodes */
36675897234Sdrh   ExprList *pList;       /* A list of expressions used as a function argument */
36775897234Sdrh   Token token;           /* An operand token */
368e1b6a5b8Sdrh   Token span;            /* Complete text of the expression */
369967e8b73Sdrh   int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
370967e8b73Sdrh                          ** iColumn-th field of the iTable-th table.  When
371967e8b73Sdrh                          ** op==TK_FUNCTION, iColumn holds the function id */
372967e8b73Sdrh   int iAgg;              /* When op==TK_COLUMN and pParse->useAgg==TRUE, pull
373967e8b73Sdrh                          ** result from the iAgg-th element of the aggregator */
37419a775c2Sdrh   Select *pSelect;       /* When the expression is a sub-select */
37575897234Sdrh };
37675897234Sdrh 
37775897234Sdrh /*
37875897234Sdrh ** A list of expressions.  Each expression may optionally have a
37975897234Sdrh ** name.  An expr/name combination can be used in several ways, such
38075897234Sdrh ** as the list of "expr AS ID" fields following a "SELECT" or in the
38175897234Sdrh ** list of "ID = expr" items in an UPDATE.  A list of expressions can
38275897234Sdrh ** also be used as the argument to a function, in which case the azName
38375897234Sdrh ** field is not used.
38475897234Sdrh */
38575897234Sdrh struct ExprList {
38675897234Sdrh   int nExpr;             /* Number of expressions on the list */
3876d4abfbeSdrh   struct ExprList_item {
38875897234Sdrh     Expr *pExpr;           /* The list of expressions */
38975897234Sdrh     char *zName;           /* Token associated with this expression */
390d8bc7086Sdrh     char sortOrder;        /* 1 for DESC or 0 for ASC */
391d8bc7086Sdrh     char isAgg;            /* True if this is an aggregate like count(*) */
392d8bc7086Sdrh     char done;             /* A flag to indicate when processing is finished */
39375897234Sdrh   } *a;                  /* One entry for each expression */
39475897234Sdrh };
39575897234Sdrh 
39675897234Sdrh /*
39775897234Sdrh ** A list of identifiers.
39875897234Sdrh */
39975897234Sdrh struct IdList {
40075897234Sdrh   int nId;         /* Number of identifiers on the list */
4016d4abfbeSdrh   struct IdList_item {
40275897234Sdrh     char *zName;      /* Text of the identifier. */
40375897234Sdrh     char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
404967e8b73Sdrh     int idx;          /* Index in some Table.aCol[] of a column named zName */
405daffd0e5Sdrh     Table *pTab;      /* An SQL table corresponding to zName */
406daffd0e5Sdrh     Select *pSelect;  /* A SELECT statement used in place of a table name */
40775897234Sdrh   } *a;            /* One entry for each identifier on the list */
40875897234Sdrh };
40975897234Sdrh 
41075897234Sdrh /*
4116b56344dSdrh ** For each nested loop in a WHERE clause implementation, the WhereInfo
4126b56344dSdrh ** structure contains a single instance of this structure.  This structure
4136b56344dSdrh ** is intended to be private the the where.c module and should not be
4146b56344dSdrh ** access or modified by other modules.
4156b56344dSdrh */
4166b56344dSdrh struct WhereLevel {
4176b56344dSdrh   int iMem;            /* Memory cell used by this level */
4186b56344dSdrh   Index *pIdx;         /* Index used */
4196b56344dSdrh   int iCur;            /* Cursor number used for this index */
420487ab3caSdrh   int score;           /* How well this indexed scored */
4216b56344dSdrh   int brk;             /* Jump here to break out of the loop */
4226b56344dSdrh   int cont;            /* Jump here to continue with the next loop cycle */
4236b56344dSdrh   int op, p1, p2;      /* Opcode used to terminate the loop */
4246b56344dSdrh };
4256b56344dSdrh 
4266b56344dSdrh /*
42775897234Sdrh ** The WHERE clause processing routine has two halves.  The
42875897234Sdrh ** first part does the start of the WHERE loop and the second
42975897234Sdrh ** half does the tail of the WHERE loop.  An instance of
43075897234Sdrh ** this structure is returned by the first half and passed
43175897234Sdrh ** into the second half to give some continuity.
43275897234Sdrh */
43375897234Sdrh struct WhereInfo {
43475897234Sdrh   Parse *pParse;
43519a775c2Sdrh   IdList *pTabList;    /* List of tables in the join */
43619a775c2Sdrh   int iContinue;       /* Jump here to continue with next record */
43719a775c2Sdrh   int iBreak;          /* Jump here to break out of the loop */
43819a775c2Sdrh   int base;            /* Index of first Open opcode */
4396b56344dSdrh   int nLevel;          /* Number of nested loop */
440832508b7Sdrh   int savedNTab;       /* Value of pParse->nTab before WhereBegin() */
441832508b7Sdrh   int peakNTab;        /* Value of pParse->nTab after WhereBegin() */
4426b56344dSdrh   WhereLevel a[1];     /* Information about each nest loop in the WHERE */
44375897234Sdrh };
44475897234Sdrh 
44575897234Sdrh /*
4469bb61fe7Sdrh ** An instance of the following structure contains all information
4479bb61fe7Sdrh ** needed to generate code for a single SELECT statement.
448a76b5dfcSdrh **
449a76b5dfcSdrh ** The zSelect field is used when the Select structure must be persistent.
450a76b5dfcSdrh ** Normally, the expression tree points to tokens in the original input
451a76b5dfcSdrh ** string that encodes the select.  But if the Select structure must live
452a76b5dfcSdrh ** longer than its input string (for example when it is used to describe
453a76b5dfcSdrh ** a VIEW) we have to make a copy of the input string so that the nodes
454a76b5dfcSdrh ** of the expression tree will have something to point to.  zSelect is used
455a76b5dfcSdrh ** to hold that copy.
4569bb61fe7Sdrh */
4579bb61fe7Sdrh struct Select {
4589bb61fe7Sdrh   int isDistinct;        /* True if the DISTINCT keyword is present */
4599bb61fe7Sdrh   ExprList *pEList;      /* The fields of the result */
4609bb61fe7Sdrh   IdList *pSrc;          /* The FROM clause */
4619bb61fe7Sdrh   Expr *pWhere;          /* The WHERE clause */
4629bb61fe7Sdrh   ExprList *pGroupBy;    /* The GROUP BY clause */
4639bb61fe7Sdrh   Expr *pHaving;         /* The HAVING clause */
4649bb61fe7Sdrh   ExprList *pOrderBy;    /* The ORDER BY clause */
46582c3d636Sdrh   int op;                /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
466967e8b73Sdrh   Select *pPrior;        /* Prior select in a compound select statement */
4679bbca4c1Sdrh   int nLimit, nOffset;   /* LIMIT and OFFSET values.  -1 means not used */
468a76b5dfcSdrh   char *zSelect;         /* Complete text of the SELECT command */
469832508b7Sdrh   int base;              /* Index of VDBE cursor for left-most FROM table */
4709bb61fe7Sdrh };
4719bb61fe7Sdrh 
4729bb61fe7Sdrh /*
473fef5208cSdrh ** The results of a select can be distributed in several ways.
474fef5208cSdrh */
475fef5208cSdrh #define SRT_Callback     1  /* Invoke a callback with each row of result */
476fef5208cSdrh #define SRT_Mem          2  /* Store result in a memory cell */
47782c3d636Sdrh #define SRT_Set          3  /* Store result as unique keys in a table */
47882c3d636Sdrh #define SRT_Union        5  /* Store result as keys in a table */
47982c3d636Sdrh #define SRT_Except       6  /* Remove result from a UNION table */
4805974a30fSdrh #define SRT_Table        7  /* Store result as data with a unique key */
4812d0794e3Sdrh #define SRT_TempTable    8  /* Store result in a trasient table */
482fef5208cSdrh 
483fef5208cSdrh /*
4842282792aSdrh ** When a SELECT uses aggregate functions (like "count(*)" or "avg(f1)")
4852282792aSdrh ** we have to do some additional analysis of expressions.  An instance
4862282792aSdrh ** of the following structure holds information about a single subexpression
4872282792aSdrh ** somewhere in the SELECT statement.  An array of these structures holds
4882282792aSdrh ** all the information we need to generate code for aggregate
4892282792aSdrh ** expressions.
4902282792aSdrh **
4912282792aSdrh ** Note that when analyzing a SELECT containing aggregates, both
4922282792aSdrh ** non-aggregate field variables and aggregate functions are stored
4932282792aSdrh ** in the AggExpr array of the Parser structure.
4942282792aSdrh **
4952282792aSdrh ** The pExpr field points to an expression that is part of either the
4962282792aSdrh ** field list, the GROUP BY clause, the HAVING clause or the ORDER BY
4972282792aSdrh ** clause.  The expression will be freed when those clauses are cleaned
4982282792aSdrh ** up.  Do not try to delete the expression attached to AggExpr.pExpr.
4992282792aSdrh **
5002282792aSdrh ** If AggExpr.pExpr==0, that means the expression is "count(*)".
5012282792aSdrh */
5022282792aSdrh struct AggExpr {
5032282792aSdrh   int isAgg;        /* if TRUE contains an aggregate function */
5042282792aSdrh   Expr *pExpr;      /* The expression */
5050bce8354Sdrh   FuncDef *pFunc;   /* Information about the aggregate function */
5062282792aSdrh };
5072282792aSdrh 
5082282792aSdrh /*
509f57b3399Sdrh ** An SQL parser context.  A copy of this structure is passed through
510f57b3399Sdrh ** the parser and down into all the parser action routine in order to
511f57b3399Sdrh ** carry around information that is global to the entire parse.
51275897234Sdrh */
51375897234Sdrh struct Parse {
51475897234Sdrh   sqlite *db;          /* The main database structure */
5155e00f6c7Sdrh   Btree *pBe;          /* The database backend */
5164c504391Sdrh   int rc;              /* Return code from execution */
51775897234Sdrh   sqlite_callback xCallback;  /* The callback function */
51875897234Sdrh   void *pArg;          /* First argument to the callback function */
51975897234Sdrh   char *zErrMsg;       /* An error message */
52075897234Sdrh   Token sErrToken;     /* The token at which the error occurred */
52175897234Sdrh   Token sFirstToken;   /* The first token parsed */
52275897234Sdrh   Token sLastToken;    /* The last token parsed */
52375897234Sdrh   Table *pNewTable;    /* A table being constructed by CREATE TABLE */
52475897234Sdrh   Vdbe *pVdbe;         /* An engine for executing database bytecode */
525d8bc7086Sdrh   int colNamesSet;     /* TRUE after OP_ColumnCount has been issued to pVdbe */
52675897234Sdrh   int explain;         /* True if the EXPLAIN flag is found on the query */
52775897234Sdrh   int initFlag;        /* True if reparsing CREATE TABLEs */
528f57b3399Sdrh   int nameClash;       /* A permanent table name clashes with temp table name */
529d78eeee1Sdrh   int newTnum;         /* Table number to use when reparsing CREATE TABLEs */
53075897234Sdrh   int nErr;            /* Number of errors seen */
531832508b7Sdrh   int nTab;            /* Number of previously allocated VDBE cursors */
53219a775c2Sdrh   int nMem;            /* Number of memory cells used so far */
533fef5208cSdrh   int nSet;            /* Number of sets used so far */
5342282792aSdrh   int nAgg;            /* Number of aggregate expressions */
5352282792aSdrh   AggExpr *aAgg;       /* An array of aggregate expressions */
5362282792aSdrh   int useAgg;          /* If true, extract field values from the aggregator
5372282792aSdrh                        ** while generating expressions.  Normally false */
53850e5dadfSdrh   int schemaVerified;  /* True if an OP_VerifySchema has been coded someplace
53950e5dadfSdrh                        ** other than after an OP_Transaction */
54075897234Sdrh };
54175897234Sdrh 
54275897234Sdrh /*
54375897234Sdrh ** Internal function prototypes
54475897234Sdrh */
54575897234Sdrh int sqliteStrICmp(const char *, const char *);
54675897234Sdrh int sqliteStrNICmp(const char *, const char *, int);
54775897234Sdrh int sqliteHashNoCase(const char *, int);
54875897234Sdrh int sqliteCompare(const char *, const char *);
54975897234Sdrh int sqliteSortCompare(const char *, const char *);
5509bbca4c1Sdrh void sqliteRealToSortable(double r, char *);
551dcc581ccSdrh #ifdef MEMORY_DEBUG
552dcc581ccSdrh   void *sqliteMalloc_(int,char*,int);
553dcc581ccSdrh   void sqliteFree_(void*,char*,int);
554dcc581ccSdrh   void *sqliteRealloc_(void*,int,char*,int);
5556e142f54Sdrh   char *sqliteStrDup_(const char*,char*,int);
5566e142f54Sdrh   char *sqliteStrNDup_(const char*, int,char*,int);
557dcc581ccSdrh #else
55875897234Sdrh   void *sqliteMalloc(int);
55975897234Sdrh   void sqliteFree(void*);
56075897234Sdrh   void *sqliteRealloc(void*,int);
5616e142f54Sdrh   char *sqliteStrDup(const char*);
5626e142f54Sdrh   char *sqliteStrNDup(const char*, int);
563dcc581ccSdrh #endif
56475897234Sdrh void sqliteSetString(char **, const char *, ...);
56575897234Sdrh void sqliteSetNString(char **, ...);
566982cef7eSdrh void sqliteDequote(char*);
56717f71934Sdrh int sqliteKeywordCode(const char*, int);
56880ff32f5Sdrh int sqliteRunParser(Parse*, const char*, char **);
56975897234Sdrh void sqliteExec(Parse*);
57075897234Sdrh Expr *sqliteExpr(int, Expr*, Expr*, Token*);
571e1b6a5b8Sdrh void sqliteExprSpan(Expr*,Token*,Token*);
57275897234Sdrh Expr *sqliteExprFunction(ExprList*, Token*);
57375897234Sdrh void sqliteExprDelete(Expr*);
57475897234Sdrh ExprList *sqliteExprListAppend(ExprList*,Expr*,Token*);
57575897234Sdrh void sqliteExprListDelete(ExprList*);
576f57b14a6Sdrh void sqlitePragma(Parse*,Token*,Token*,int);
5775e00f6c7Sdrh void sqliteCommitInternalChanges(sqlite*);
5785e00f6c7Sdrh void sqliteRollbackInternalChanges(sqlite*);
579969fa7c1Sdrh Table *sqliteResultSetOfSelect(Parse*,char*,Select*);
580f57b3399Sdrh void sqliteStartTable(Parse*,Token*,Token*,int);
58175897234Sdrh void sqliteAddColumn(Parse*,Token*);
5829cfcf5d4Sdrh void sqliteAddNotNull(Parse*, int);
5839cfcf5d4Sdrh void sqliteAddPrimaryKey(Parse*, IdList*, int);
584382c0247Sdrh void sqliteAddColumnType(Parse*,Token*,Token*);
5857020f651Sdrh void sqliteAddDefaultValue(Parse*,Token*,int);
586969fa7c1Sdrh void sqliteEndTable(Parse*,Token*,Select*);
587a76b5dfcSdrh void sqliteCreateView(Parse*,Token*,Token*,Select*);
588417be79cSdrh int sqliteViewGetColumnNames(Parse*,Table*);
589417be79cSdrh void sqliteViewResetAll(sqlite*);
5904ff6dfa7Sdrh void sqliteDropTable(Parse*, Token*, int);
59175897234Sdrh void sqliteDeleteTable(sqlite*, Table*);
5929cfcf5d4Sdrh void sqliteInsert(Parse*, Token*, ExprList*, Select*, IdList*, int);
59375897234Sdrh IdList *sqliteIdListAppend(IdList*, Token*);
59475897234Sdrh void sqliteIdListAddAlias(IdList*, Token*);
59575897234Sdrh void sqliteIdListDelete(IdList*);
596717e6402Sdrh void sqliteCreateIndex(Parse*, Token*, Token*, IdList*, int, Token*, Token*);
59775897234Sdrh void sqliteDropIndex(Parse*, Token*);
5981b2e0329Sdrh int sqliteSelect(Parse*, Select*, int, int, Select*, int, int*);
5999bbca4c1Sdrh Select *sqliteSelectNew(ExprList*,IdList*,Expr*,ExprList*,Expr*,ExprList*,
6009bbca4c1Sdrh                         int,int,int);
6019bb61fe7Sdrh void sqliteSelectDelete(Select*);
602ff78bd2fSdrh void sqliteSelectUnbind(Select*);
603a76b5dfcSdrh Table *sqliteTableNameToTable(Parse*, const char*);
604a76b5dfcSdrh IdList *sqliteTableTokenToIdList(Parse*, Token*);
60575897234Sdrh void sqliteDeleteFrom(Parse*, Token*, Expr*);
6069cfcf5d4Sdrh void sqliteUpdate(Parse*, Token*, ExprList*, Expr*, int);
607832508b7Sdrh WhereInfo *sqliteWhereBegin(Parse*, int, IdList*, Expr*, int);
60875897234Sdrh void sqliteWhereEnd(WhereInfo*);
60975897234Sdrh void sqliteExprCode(Parse*, Expr*);
61075897234Sdrh void sqliteExprIfTrue(Parse*, Expr*, int);
61175897234Sdrh void sqliteExprIfFalse(Parse*, Expr*, int);
612a76b5dfcSdrh Table *sqliteFindTable(sqlite*,const char*);
613a76b5dfcSdrh Index *sqliteFindIndex(sqlite*,const char*);
6146d4abfbeSdrh void sqliteUnlinkAndDeleteIndex(sqlite*,Index*);
615b419a926Sdrh void sqliteCopy(Parse*, Token*, Token*, Token*, int);
616dce2cbe6Sdrh void sqliteVacuum(Parse*, Token*);
617e17a7e33Sdrh int sqliteGlobCompare(const unsigned char*,const unsigned char*);
618dce2cbe6Sdrh int sqliteLikeCompare(const unsigned char*,const unsigned char*);
619cce7d176Sdrh char *sqliteTableNameFromToken(Token*);
620cce7d176Sdrh int sqliteExprCheck(Parse*, Expr*, int, int*);
621d8bc7086Sdrh int sqliteExprCompare(Expr*, Expr*);
622cce7d176Sdrh int sqliteFuncId(Token*);
623832508b7Sdrh int sqliteExprResolveIds(Parse*, int, IdList*, ExprList*, Expr*);
6242282792aSdrh int sqliteExprAnalyzeAggregates(Parse*, Expr*);
625d8bc7086Sdrh Vdbe *sqliteGetVdbe(Parse*);
626b8ca307eSdrh int sqliteRandomByte(void);
627b8ca307eSdrh int sqliteRandomInteger(void);
6281c92853dSdrh void sqliteBeginTransaction(Parse*, int);
629c4a3c779Sdrh void sqliteCommitTransaction(Parse*);
630c4a3c779Sdrh void sqliteRollbackTransaction(Parse*);
631d1bf3512Sdrh char *sqlite_mprintf(const char *, ...);
6329208643dSdrh int sqliteExprIsConstant(Expr*);
6330ca3e24bSdrh void sqliteGenerateRowDelete(Vdbe*, Table*, int);
6340ca3e24bSdrh void sqliteGenerateRowIndexDelete(Vdbe*, Table*, int, char*);
6350ca3e24bSdrh void sqliteGenerateConstraintChecks(Parse*,Table*,int,char*,int,int,int,int);
636b419a926Sdrh void sqliteCompleteInsertion(Parse*, Table*, int, char*, int, int);
6371c92853dSdrh void sqliteBeginWriteOperation(Parse*);
638663fc63aSdrh void sqliteBeginMultiWriteOperation(Parse*);
6391c92853dSdrh void sqliteEndWriteOperation(Parse*);
640a76b5dfcSdrh void sqliteExprMoveStrings(Expr*, int);
641a76b5dfcSdrh void sqliteExprListMoveStrings(ExprList*, int);
642a76b5dfcSdrh void sqliteSelectMoveStrings(Select*, int);
643ff78bd2fSdrh Expr *sqliteExprDup(Expr*);
644ff78bd2fSdrh ExprList *sqliteExprListDup(ExprList*);
645ff78bd2fSdrh IdList *sqliteIdListDup(IdList*);
646ff78bd2fSdrh Select *sqliteSelectDup(Select*);
6470bce8354Sdrh FuncDef *sqliteFindFunction(sqlite*,const char*,int,int,int);
648dc04c583Sdrh void sqliteRegisterBuildinFunctions(sqlite*);
649