xref: /sqlite-3.40.0/src/sqliteInt.h (revision 2d0794e3)
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*2d0794e3Sdrh ** @(#) $Id: sqliteInt.h,v 1.99 2002/03/03 03:03:53 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 */
30f57b14a6Sdrh #define MAX_PAGES   100
31f57b14a6Sdrh #define TEMP_PAGES   25
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 */
1582803757aSdrh   int nTable;                   /* Number of tables in the database */
1592dfbbcafSdrh   void *pBusyArg;               /* 1st Argument to the busy callback */
160353f57e0Sdrh   int (*xBusyCallback)(void *,const char*,int);  /* The busy callback */
161beae3194Sdrh   Hash tblHash;                 /* All tables indexed by name */
162beae3194Sdrh   Hash idxHash;                 /* All (named) indices indexed by name */
16374e24cd0Sdrh   Hash tblDrop;                 /* Uncommitted DROP TABLEs */
16474e24cd0Sdrh   Hash idxDrop;                 /* Uncommitted DROP INDEXs */
1650bce8354Sdrh   Hash aFunc;                   /* All functions that can be in SQL exprs */
166af9ff33aSdrh   int lastRowid;                /* ROWID of most recent insert */
1675cf8e8c7Sdrh   int priorNewRowid;            /* Last randomly generated ROWID */
1681c92853dSdrh   int onError;                  /* Default conflict algorithm */
16975897234Sdrh };
17075897234Sdrh 
17175897234Sdrh /*
172967e8b73Sdrh ** Possible values for the sqlite.flags.
17375897234Sdrh */
1744c504391Sdrh #define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
1754c504391Sdrh #define SQLITE_Initialized    0x00000002  /* True after initialization */
1764c504391Sdrh #define SQLITE_Interrupt      0x00000004  /* Cancel current operation */
177c4a3c779Sdrh #define SQLITE_InTrans        0x00000008  /* True if in a transaction */
1785e00f6c7Sdrh #define SQLITE_InternChanges  0x00000010  /* Uncommitted Hash table changes */
179382c0247Sdrh #define SQLITE_FullColNames   0x00000020  /* Show full column names on SELECT */
1801bee3d7bSdrh #define SQLITE_CountRows      0x00000040  /* Count rows changed by INSERT, */
1811bee3d7bSdrh                                           /*   DELETE, or UPDATE and return */
1821bee3d7bSdrh                                           /*   the count using a callback. */
1836a535340Sdrh #define SQLITE_NullCallback   0x00000080  /* Invoke the callback once if the */
1846a535340Sdrh                                           /*   result set is empty */
185c3a64ba0Sdrh #define SQLITE_ResultDetails  0x00000100  /* Details added to result set */
18658b9576bSdrh 
18758b9576bSdrh /*
1880bce8354Sdrh ** Each SQL function is defined by an instance of the following
1890bce8354Sdrh ** structure.  A pointer to this structure is stored in the sqlite.aFunc
1908e0a2f90Sdrh ** hash table.  When multiple functions have the same name, the hash table
1918e0a2f90Sdrh ** points to a linked list of these structures.
1922803757aSdrh */
1930bce8354Sdrh struct FuncDef {
1941350b030Sdrh   void (*xFunc)(sqlite_func*,int,const char**);   /* Regular function */
1951350b030Sdrh   void *(*xStep)(sqlite_func*,int,const char**);  /* Aggregate function step */
1961350b030Sdrh   void (*xFinalize)(sqlite_func*);           /* Aggregate function finializer */
1978e0a2f90Sdrh   int nArg;                                  /* Number of arguments */
1981350b030Sdrh   void *pUserData;                           /* User data parameter */
1990bce8354Sdrh   FuncDef *pNext;                            /* Next function with same name */
2008e0a2f90Sdrh };
2012803757aSdrh 
2022803757aSdrh /*
203967e8b73Sdrh ** information about each column of an SQL table is held in an instance
2047020f651Sdrh ** of this structure.
2057020f651Sdrh */
2067020f651Sdrh struct Column {
2077020f651Sdrh   char *zName;     /* Name of this column */
2087020f651Sdrh   char *zDflt;     /* Default value of this column */
209382c0247Sdrh   char *zType;     /* Data type for this column */
2104a32431cSdrh   u8 notNull;      /* True if there is a NOT NULL constraint */
2114a32431cSdrh   u8 isPrimKey;    /* True if this column is an INTEGER PRIMARY KEY */
2127020f651Sdrh };
2137020f651Sdrh 
2147020f651Sdrh /*
21522f70c32Sdrh ** Each SQL table is represented in memory by an instance of the
21622f70c32Sdrh ** following structure.
21722f70c32Sdrh **
21822f70c32Sdrh ** Expr.zName is the name of the table.  The case of the original
21922f70c32Sdrh ** CREATE TABLE statement is stored, but case is not significant for
22022f70c32Sdrh ** comparisons.
22122f70c32Sdrh **
22222f70c32Sdrh ** Expr.nCol is the number of columns in this table.  Expr.aCol is a
22322f70c32Sdrh ** pointer to an array of Column structures, one for each column.
22422f70c32Sdrh **
22522f70c32Sdrh ** If the table has an INTEGER PRIMARY KEY, then Expr.iPKey is the index of
22622f70c32Sdrh ** the column that is that key.   Otherwise Expr.iPKey is negative.  Note
22722f70c32Sdrh ** that the datatype of the PRIMARY KEY must be INTEGER for this field to
22822f70c32Sdrh ** be set.  An INTEGER PRIMARY KEY is used as the rowid for each row of
22922f70c32Sdrh ** the table.  If a table has no INTEGER PRIMARY KEY, then a random rowid
23022f70c32Sdrh ** is generated for each row of the table.  Expr.hasPrimKey is true if
23122f70c32Sdrh ** the table has any PRIMARY KEY, INTEGER or otherwise.
23222f70c32Sdrh **
23322f70c32Sdrh ** Expr.tnum is the page number for the root BTree page of the table in the
23422f70c32Sdrh ** database file.  If Expr.isTemp is true, then this page occurs in the
23522f70c32Sdrh ** auxiliary database file, not the main database file.  If Expr.isTransient
23622f70c32Sdrh ** is true, then the table is stored in a file that is automatically deleted
23722f70c32Sdrh ** when the VDBE cursor to the table is closed.  In this case Expr.tnum
23822f70c32Sdrh ** refers VDBE cursor number that holds the table open, not to the root
23922f70c32Sdrh ** page number.  Transient tables are used to hold the results of a
24022f70c32Sdrh ** sub-query that appears instead of a real table name in the FROM clause
24122f70c32Sdrh ** of a SELECT statement.
24275897234Sdrh */
24375897234Sdrh struct Table {
24475897234Sdrh   char *zName;     /* Name of the table */
24575897234Sdrh   int nCol;        /* Number of columns in this table */
2467020f651Sdrh   Column *aCol;    /* Information about each column */
247c8392586Sdrh   int iPKey;       /* If not less then 0, use aCol[iPKey] as the primary key */
248967e8b73Sdrh   Index *pIndex;   /* List of SQL indexes on this table. */
24922f70c32Sdrh   int tnum;        /* Root BTree node for this table (see note above) */
250a76b5dfcSdrh   Select *pSelect; /* NULL for tables.  Points to definition if a view. */
251717e6402Sdrh   u8 readOnly;     /* True if this table should not be written by the user */
252717e6402Sdrh   u8 isCommit;     /* True if creation of this table has been committed */
253f57b3399Sdrh   u8 isTemp;       /* True if stored in db->pBeTemp instead of db->pBe */
25422f70c32Sdrh   u8 isTransient;  /* True if automatically deleted when VDBE finishes */
2554a32431cSdrh   u8 hasPrimKey;   /* True if there exists a primary key */
2569cfcf5d4Sdrh   u8 keyConf;      /* What to do in case of uniqueness conflict on iPKey */
25775897234Sdrh };
25875897234Sdrh 
25975897234Sdrh /*
26022f70c32Sdrh ** SQLite supports 5 different ways to resolve a contraint
26122f70c32Sdrh ** error.  ROLLBACK processing means that a constraint violation
2621c92853dSdrh ** causes the operation in proces to fail and for the current transaction
2631c92853dSdrh ** to be rolled back.  ABORT processing means the operation in process
2641c92853dSdrh ** fails and any prior changes from that one operation are backed out,
2651c92853dSdrh ** but the transaction is not rolled back.  FAIL processing means that
2661c92853dSdrh ** the operation in progress stops and returns an error code.  But prior
2671c92853dSdrh ** changes due to the same operation are not backed out and no rollback
2681c92853dSdrh ** occurs.  IGNORE means that the particular row that caused the constraint
2691c92853dSdrh ** error is not inserted or updated.  Processing continues and no error
2701c92853dSdrh ** is returned.  REPLACE means that preexisting database rows that caused
2711c92853dSdrh ** a UNIQUE constraint violation are removed so that the new insert or
2721c92853dSdrh ** update can proceed.  Processing continues and no error is reported.
2731c92853dSdrh **
2741c92853dSdrh ** The following there symbolic values are used to record which type
2751c92853dSdrh ** of action to take.
2769cfcf5d4Sdrh */
2779cfcf5d4Sdrh #define OE_None     0   /* There is no constraint to check */
2781c92853dSdrh #define OE_Rollback 1   /* Fail the operation and rollback the transaction */
2791c92853dSdrh #define OE_Abort    2   /* Back out changes but do no rollback transaction */
2801c92853dSdrh #define OE_Fail     3   /* Stop the operation but leave all prior changes */
2811c92853dSdrh #define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */
2821c92853dSdrh #define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */
2839cfcf5d4Sdrh #define OE_Default  9   /* Do whatever the default action is */
2849cfcf5d4Sdrh 
2859cfcf5d4Sdrh /*
28666b89c8fSdrh ** Each SQL index is represented in memory by an
28775897234Sdrh ** instance of the following structure.
288967e8b73Sdrh **
289967e8b73Sdrh ** The columns of the table that are to be indexed are described
290967e8b73Sdrh ** by the aiColumn[] field of this structure.  For example, suppose
291967e8b73Sdrh ** we have the following table and index:
292967e8b73Sdrh **
293967e8b73Sdrh **     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
294967e8b73Sdrh **     CREATE INDEX Ex2 ON Ex1(c3,c1);
295967e8b73Sdrh **
296967e8b73Sdrh ** In the Table structure describing Ex1, nCol==3 because there are
297967e8b73Sdrh ** three columns in the table.  In the Index structure describing
298967e8b73Sdrh ** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
299967e8b73Sdrh ** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the
300967e8b73Sdrh ** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
301967e8b73Sdrh ** The second column to be indexed (c1) has an index of 0 in
302967e8b73Sdrh ** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
30375897234Sdrh */
30475897234Sdrh struct Index {
30575897234Sdrh   char *zName;     /* Name of this index */
306967e8b73Sdrh   int nColumn;     /* Number of columns in the table used by this index */
307967e8b73Sdrh   int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
308967e8b73Sdrh   Table *pTable;   /* The SQL table being indexed */
309be0072d2Sdrh   int tnum;        /* Page containing root of this index in database file */
3109cfcf5d4Sdrh   u8 isUnique;     /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
311717e6402Sdrh   u8 isCommit;     /* True if creation of this index has been committed */
31274e24cd0Sdrh   u8 isDropped;    /* True if a DROP INDEX has executed on this index */
3139cfcf5d4Sdrh   u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
31475897234Sdrh   Index *pNext;    /* The next index associated with the same table */
31575897234Sdrh };
31675897234Sdrh 
31775897234Sdrh /*
31875897234Sdrh ** Each token coming out of the lexer is an instance of
31975897234Sdrh ** this structure.
32075897234Sdrh */
32175897234Sdrh struct Token {
32280ff32f5Sdrh   const char *z;      /* Text of the token.  Not NULL-terminated! */
32375897234Sdrh   int n;              /* Number of characters in this token */
32475897234Sdrh };
32575897234Sdrh 
32675897234Sdrh /*
32775897234Sdrh ** Each node of an expression in the parse tree is an instance
32822f70c32Sdrh ** of this structure.
32922f70c32Sdrh **
33022f70c32Sdrh ** Expr.op is the opcode.  The integer parser token codes are reused
33122f70c32Sdrh ** as opcodes here.  For example, the parser defines TK_GE to be an integer
33222f70c32Sdrh ** code representing the ">=" operator.  This same integer code is reused
33322f70c32Sdrh ** to represent the greater-than-or-equal-to operator in the expression
33422f70c32Sdrh ** tree.
33522f70c32Sdrh **
33622f70c32Sdrh ** Expr.pRight and Expr.pLeft are subexpressions.  Expr.pList is a list
33722f70c32Sdrh ** of argument if the expression is a function.
33822f70c32Sdrh **
33922f70c32Sdrh ** Expr.token is the operator token for this node.  Expr.span is the complete
34022f70c32Sdrh ** subexpression represented by this node and all its decendents.  These
34122f70c32Sdrh ** fields are used for error reporting and for reconstructing the text of
34222f70c32Sdrh ** an expression to use as the column name in a SELECT statement.
34322f70c32Sdrh **
34422f70c32Sdrh ** An expression of the form ID or ID.ID refers to a column in a table.
34522f70c32Sdrh ** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
34622f70c32Sdrh ** the integer cursor number of a VDBE cursor pointing to that table and
34722f70c32Sdrh ** Expr.iColumn is the column number for the specific column.  If the
34822f70c32Sdrh ** expression is used as a result in an aggregate SELECT, then the
34922f70c32Sdrh ** value is also stored in the Expr.iAgg column in the aggregate so that
35022f70c32Sdrh ** it can be accessed after all aggregates are computed.
35122f70c32Sdrh **
35222f70c32Sdrh ** If the expression is a function, the Expr.iTable is an integer code
35322f70c32Sdrh ** representing which function.
35422f70c32Sdrh **
35522f70c32Sdrh ** The Expr.pSelect field points to a SELECT statement.  The SELECT might
35622f70c32Sdrh ** be the right operand of an IN operator.  Or, if a scalar SELECT appears
35722f70c32Sdrh ** in an expression the opcode is TK_SELECT and Expr.pSelect is the only
35822f70c32Sdrh ** operand.
35975897234Sdrh */
36075897234Sdrh struct Expr {
36175897234Sdrh   int op;                /* Operation performed by this node */
36275897234Sdrh   Expr *pLeft, *pRight;  /* Left and right subnodes */
36375897234Sdrh   ExprList *pList;       /* A list of expressions used as a function argument */
36475897234Sdrh   Token token;           /* An operand token */
365e1b6a5b8Sdrh   Token span;            /* Complete text of the expression */
366967e8b73Sdrh   int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
367967e8b73Sdrh                          ** iColumn-th field of the iTable-th table.  When
368967e8b73Sdrh                          ** op==TK_FUNCTION, iColumn holds the function id */
369967e8b73Sdrh   int iAgg;              /* When op==TK_COLUMN and pParse->useAgg==TRUE, pull
370967e8b73Sdrh                          ** result from the iAgg-th element of the aggregator */
37119a775c2Sdrh   Select *pSelect;       /* When the expression is a sub-select */
37275897234Sdrh };
37375897234Sdrh 
37475897234Sdrh /*
37575897234Sdrh ** A list of expressions.  Each expression may optionally have a
37675897234Sdrh ** name.  An expr/name combination can be used in several ways, such
37775897234Sdrh ** as the list of "expr AS ID" fields following a "SELECT" or in the
37875897234Sdrh ** list of "ID = expr" items in an UPDATE.  A list of expressions can
37975897234Sdrh ** also be used as the argument to a function, in which case the azName
38075897234Sdrh ** field is not used.
38175897234Sdrh */
38275897234Sdrh struct ExprList {
38375897234Sdrh   int nExpr;             /* Number of expressions on the list */
3846d4abfbeSdrh   struct ExprList_item {
38575897234Sdrh     Expr *pExpr;           /* The list of expressions */
38675897234Sdrh     char *zName;           /* Token associated with this expression */
387d8bc7086Sdrh     char sortOrder;        /* 1 for DESC or 0 for ASC */
388d8bc7086Sdrh     char isAgg;            /* True if this is an aggregate like count(*) */
389d8bc7086Sdrh     char done;             /* A flag to indicate when processing is finished */
39075897234Sdrh   } *a;                  /* One entry for each expression */
39175897234Sdrh };
39275897234Sdrh 
39375897234Sdrh /*
39475897234Sdrh ** A list of identifiers.
39575897234Sdrh */
39675897234Sdrh struct IdList {
39775897234Sdrh   int nId;         /* Number of identifiers on the list */
3986d4abfbeSdrh   struct IdList_item {
39975897234Sdrh     char *zName;      /* Text of the identifier. */
40075897234Sdrh     char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
401967e8b73Sdrh     int idx;          /* Index in some Table.aCol[] of a column named zName */
402daffd0e5Sdrh     Table *pTab;      /* An SQL table corresponding to zName */
403daffd0e5Sdrh     Select *pSelect;  /* A SELECT statement used in place of a table name */
40475897234Sdrh   } *a;            /* One entry for each identifier on the list */
40575897234Sdrh };
40675897234Sdrh 
40775897234Sdrh /*
4086b56344dSdrh ** For each nested loop in a WHERE clause implementation, the WhereInfo
4096b56344dSdrh ** structure contains a single instance of this structure.  This structure
4106b56344dSdrh ** is intended to be private the the where.c module and should not be
4116b56344dSdrh ** access or modified by other modules.
4126b56344dSdrh */
4136b56344dSdrh struct WhereLevel {
4146b56344dSdrh   int iMem;            /* Memory cell used by this level */
4156b56344dSdrh   Index *pIdx;         /* Index used */
4166b56344dSdrh   int iCur;            /* Cursor number used for this index */
417487ab3caSdrh   int score;           /* How well this indexed scored */
4186b56344dSdrh   int brk;             /* Jump here to break out of the loop */
4196b56344dSdrh   int cont;            /* Jump here to continue with the next loop cycle */
4206b56344dSdrh   int op, p1, p2;      /* Opcode used to terminate the loop */
4216b56344dSdrh };
4226b56344dSdrh 
4236b56344dSdrh /*
42475897234Sdrh ** The WHERE clause processing routine has two halves.  The
42575897234Sdrh ** first part does the start of the WHERE loop and the second
42675897234Sdrh ** half does the tail of the WHERE loop.  An instance of
42775897234Sdrh ** this structure is returned by the first half and passed
42875897234Sdrh ** into the second half to give some continuity.
42975897234Sdrh */
43075897234Sdrh struct WhereInfo {
43175897234Sdrh   Parse *pParse;
43219a775c2Sdrh   IdList *pTabList;    /* List of tables in the join */
43319a775c2Sdrh   int iContinue;       /* Jump here to continue with next record */
43419a775c2Sdrh   int iBreak;          /* Jump here to break out of the loop */
43519a775c2Sdrh   int base;            /* Index of first Open opcode */
4366b56344dSdrh   int nLevel;          /* Number of nested loop */
437832508b7Sdrh   int savedNTab;       /* Value of pParse->nTab before WhereBegin() */
438832508b7Sdrh   int peakNTab;        /* Value of pParse->nTab after WhereBegin() */
4396b56344dSdrh   WhereLevel a[1];     /* Information about each nest loop in the WHERE */
44075897234Sdrh };
44175897234Sdrh 
44275897234Sdrh /*
4439bb61fe7Sdrh ** An instance of the following structure contains all information
4449bb61fe7Sdrh ** needed to generate code for a single SELECT statement.
445a76b5dfcSdrh **
446a76b5dfcSdrh ** The zSelect field is used when the Select structure must be persistent.
447a76b5dfcSdrh ** Normally, the expression tree points to tokens in the original input
448a76b5dfcSdrh ** string that encodes the select.  But if the Select structure must live
449a76b5dfcSdrh ** longer than its input string (for example when it is used to describe
450a76b5dfcSdrh ** a VIEW) we have to make a copy of the input string so that the nodes
451a76b5dfcSdrh ** of the expression tree will have something to point to.  zSelect is used
452a76b5dfcSdrh ** to hold that copy.
4539bb61fe7Sdrh */
4549bb61fe7Sdrh struct Select {
4559bb61fe7Sdrh   int isDistinct;        /* True if the DISTINCT keyword is present */
4569bb61fe7Sdrh   ExprList *pEList;      /* The fields of the result */
4579bb61fe7Sdrh   IdList *pSrc;          /* The FROM clause */
4589bb61fe7Sdrh   Expr *pWhere;          /* The WHERE clause */
4599bb61fe7Sdrh   ExprList *pGroupBy;    /* The GROUP BY clause */
4609bb61fe7Sdrh   Expr *pHaving;         /* The HAVING clause */
4619bb61fe7Sdrh   ExprList *pOrderBy;    /* The ORDER BY clause */
46282c3d636Sdrh   int op;                /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
463967e8b73Sdrh   Select *pPrior;        /* Prior select in a compound select statement */
4649bbca4c1Sdrh   int nLimit, nOffset;   /* LIMIT and OFFSET values.  -1 means not used */
465a76b5dfcSdrh   char *zSelect;         /* Complete text of the SELECT command */
466832508b7Sdrh   int base;              /* Index of VDBE cursor for left-most FROM table */
4679bb61fe7Sdrh };
4689bb61fe7Sdrh 
4699bb61fe7Sdrh /*
470fef5208cSdrh ** The results of a select can be distributed in several ways.
471fef5208cSdrh */
472fef5208cSdrh #define SRT_Callback     1  /* Invoke a callback with each row of result */
473fef5208cSdrh #define SRT_Mem          2  /* Store result in a memory cell */
47482c3d636Sdrh #define SRT_Set          3  /* Store result as unique keys in a table */
47582c3d636Sdrh #define SRT_Union        5  /* Store result as keys in a table */
47682c3d636Sdrh #define SRT_Except       6  /* Remove result from a UNION table */
4775974a30fSdrh #define SRT_Table        7  /* Store result as data with a unique key */
478*2d0794e3Sdrh #define SRT_TempTable    8  /* Store result in a trasient table */
479fef5208cSdrh 
480fef5208cSdrh /*
4812282792aSdrh ** When a SELECT uses aggregate functions (like "count(*)" or "avg(f1)")
4822282792aSdrh ** we have to do some additional analysis of expressions.  An instance
4832282792aSdrh ** of the following structure holds information about a single subexpression
4842282792aSdrh ** somewhere in the SELECT statement.  An array of these structures holds
4852282792aSdrh ** all the information we need to generate code for aggregate
4862282792aSdrh ** expressions.
4872282792aSdrh **
4882282792aSdrh ** Note that when analyzing a SELECT containing aggregates, both
4892282792aSdrh ** non-aggregate field variables and aggregate functions are stored
4902282792aSdrh ** in the AggExpr array of the Parser structure.
4912282792aSdrh **
4922282792aSdrh ** The pExpr field points to an expression that is part of either the
4932282792aSdrh ** field list, the GROUP BY clause, the HAVING clause or the ORDER BY
4942282792aSdrh ** clause.  The expression will be freed when those clauses are cleaned
4952282792aSdrh ** up.  Do not try to delete the expression attached to AggExpr.pExpr.
4962282792aSdrh **
4972282792aSdrh ** If AggExpr.pExpr==0, that means the expression is "count(*)".
4982282792aSdrh */
4992282792aSdrh struct AggExpr {
5002282792aSdrh   int isAgg;        /* if TRUE contains an aggregate function */
5012282792aSdrh   Expr *pExpr;      /* The expression */
5020bce8354Sdrh   FuncDef *pFunc;   /* Information about the aggregate function */
5032282792aSdrh };
5042282792aSdrh 
5052282792aSdrh /*
506f57b3399Sdrh ** An SQL parser context.  A copy of this structure is passed through
507f57b3399Sdrh ** the parser and down into all the parser action routine in order to
508f57b3399Sdrh ** carry around information that is global to the entire parse.
50975897234Sdrh */
51075897234Sdrh struct Parse {
51175897234Sdrh   sqlite *db;          /* The main database structure */
5125e00f6c7Sdrh   Btree *pBe;          /* The database backend */
5134c504391Sdrh   int rc;              /* Return code from execution */
51475897234Sdrh   sqlite_callback xCallback;  /* The callback function */
51575897234Sdrh   void *pArg;          /* First argument to the callback function */
51675897234Sdrh   char *zErrMsg;       /* An error message */
51775897234Sdrh   Token sErrToken;     /* The token at which the error occurred */
51875897234Sdrh   Token sFirstToken;   /* The first token parsed */
51975897234Sdrh   Token sLastToken;    /* The last token parsed */
52075897234Sdrh   Table *pNewTable;    /* A table being constructed by CREATE TABLE */
52175897234Sdrh   Vdbe *pVdbe;         /* An engine for executing database bytecode */
522d8bc7086Sdrh   int colNamesSet;     /* TRUE after OP_ColumnCount has been issued to pVdbe */
52375897234Sdrh   int explain;         /* True if the EXPLAIN flag is found on the query */
52475897234Sdrh   int initFlag;        /* True if reparsing CREATE TABLEs */
525f57b3399Sdrh   int nameClash;       /* A permanent table name clashes with temp table name */
526d78eeee1Sdrh   int newTnum;         /* Table number to use when reparsing CREATE TABLEs */
52775897234Sdrh   int nErr;            /* Number of errors seen */
528832508b7Sdrh   int nTab;            /* Number of previously allocated VDBE cursors */
52919a775c2Sdrh   int nMem;            /* Number of memory cells used so far */
530fef5208cSdrh   int nSet;            /* Number of sets used so far */
5312282792aSdrh   int nAgg;            /* Number of aggregate expressions */
5322282792aSdrh   AggExpr *aAgg;       /* An array of aggregate expressions */
5332282792aSdrh   int useAgg;          /* If true, extract field values from the aggregator
5342282792aSdrh                        ** while generating expressions.  Normally false */
53550e5dadfSdrh   int schemaVerified;  /* True if an OP_VerifySchema has been coded someplace
53650e5dadfSdrh                        ** other than after an OP_Transaction */
53775897234Sdrh };
53875897234Sdrh 
53975897234Sdrh /*
54075897234Sdrh ** Internal function prototypes
54175897234Sdrh */
54275897234Sdrh int sqliteStrICmp(const char *, const char *);
54375897234Sdrh int sqliteStrNICmp(const char *, const char *, int);
54475897234Sdrh int sqliteHashNoCase(const char *, int);
54575897234Sdrh int sqliteCompare(const char *, const char *);
54675897234Sdrh int sqliteSortCompare(const char *, const char *);
5479bbca4c1Sdrh void sqliteRealToSortable(double r, char *);
548dcc581ccSdrh #ifdef MEMORY_DEBUG
549dcc581ccSdrh   void *sqliteMalloc_(int,char*,int);
550dcc581ccSdrh   void sqliteFree_(void*,char*,int);
551dcc581ccSdrh   void *sqliteRealloc_(void*,int,char*,int);
5526e142f54Sdrh   char *sqliteStrDup_(const char*,char*,int);
5536e142f54Sdrh   char *sqliteStrNDup_(const char*, int,char*,int);
554dcc581ccSdrh #else
55575897234Sdrh   void *sqliteMalloc(int);
55675897234Sdrh   void sqliteFree(void*);
55775897234Sdrh   void *sqliteRealloc(void*,int);
5586e142f54Sdrh   char *sqliteStrDup(const char*);
5596e142f54Sdrh   char *sqliteStrNDup(const char*, int);
560dcc581ccSdrh #endif
56175897234Sdrh void sqliteSetString(char **, const char *, ...);
56275897234Sdrh void sqliteSetNString(char **, ...);
563982cef7eSdrh void sqliteDequote(char*);
56417f71934Sdrh int sqliteKeywordCode(const char*, int);
56580ff32f5Sdrh int sqliteRunParser(Parse*, const char*, char **);
56675897234Sdrh void sqliteExec(Parse*);
56775897234Sdrh Expr *sqliteExpr(int, Expr*, Expr*, Token*);
568e1b6a5b8Sdrh void sqliteExprSpan(Expr*,Token*,Token*);
56975897234Sdrh Expr *sqliteExprFunction(ExprList*, Token*);
57075897234Sdrh void sqliteExprDelete(Expr*);
57175897234Sdrh ExprList *sqliteExprListAppend(ExprList*,Expr*,Token*);
57275897234Sdrh void sqliteExprListDelete(ExprList*);
573f57b14a6Sdrh void sqlitePragma(Parse*,Token*,Token*,int);
5745e00f6c7Sdrh void sqliteCommitInternalChanges(sqlite*);
5755e00f6c7Sdrh void sqliteRollbackInternalChanges(sqlite*);
576969fa7c1Sdrh Table *sqliteResultSetOfSelect(Parse*,char*,Select*);
577f57b3399Sdrh void sqliteStartTable(Parse*,Token*,Token*,int);
57875897234Sdrh void sqliteAddColumn(Parse*,Token*);
5799cfcf5d4Sdrh void sqliteAddNotNull(Parse*, int);
5809cfcf5d4Sdrh void sqliteAddPrimaryKey(Parse*, IdList*, int);
581382c0247Sdrh void sqliteAddColumnType(Parse*,Token*,Token*);
5827020f651Sdrh void sqliteAddDefaultValue(Parse*,Token*,int);
583969fa7c1Sdrh void sqliteEndTable(Parse*,Token*,Select*);
584a76b5dfcSdrh void sqliteCreateView(Parse*,Token*,Token*,Select*);
58575897234Sdrh void sqliteDropTable(Parse*, Token*);
58675897234Sdrh void sqliteDeleteTable(sqlite*, Table*);
5879cfcf5d4Sdrh void sqliteInsert(Parse*, Token*, ExprList*, Select*, IdList*, int);
58875897234Sdrh IdList *sqliteIdListAppend(IdList*, Token*);
58975897234Sdrh void sqliteIdListAddAlias(IdList*, Token*);
59075897234Sdrh void sqliteIdListDelete(IdList*);
591717e6402Sdrh void sqliteCreateIndex(Parse*, Token*, Token*, IdList*, int, Token*, Token*);
59275897234Sdrh void sqliteDropIndex(Parse*, Token*);
5931b2e0329Sdrh int sqliteSelect(Parse*, Select*, int, int, Select*, int, int*);
5949bbca4c1Sdrh Select *sqliteSelectNew(ExprList*,IdList*,Expr*,ExprList*,Expr*,ExprList*,
5959bbca4c1Sdrh                         int,int,int);
5969bb61fe7Sdrh void sqliteSelectDelete(Select*);
597ff78bd2fSdrh void sqliteSelectUnbind(Select*);
598a76b5dfcSdrh Table *sqliteTableNameToTable(Parse*, const char*);
599a76b5dfcSdrh IdList *sqliteTableTokenToIdList(Parse*, Token*);
60075897234Sdrh void sqliteDeleteFrom(Parse*, Token*, Expr*);
6019cfcf5d4Sdrh void sqliteUpdate(Parse*, Token*, ExprList*, Expr*, int);
602832508b7Sdrh WhereInfo *sqliteWhereBegin(Parse*, int, IdList*, Expr*, int);
60375897234Sdrh void sqliteWhereEnd(WhereInfo*);
60475897234Sdrh void sqliteExprCode(Parse*, Expr*);
60575897234Sdrh void sqliteExprIfTrue(Parse*, Expr*, int);
60675897234Sdrh void sqliteExprIfFalse(Parse*, Expr*, int);
607a76b5dfcSdrh Table *sqliteFindTable(sqlite*,const char*);
608a76b5dfcSdrh Index *sqliteFindIndex(sqlite*,const char*);
6096d4abfbeSdrh void sqliteUnlinkAndDeleteIndex(sqlite*,Index*);
610b419a926Sdrh void sqliteCopy(Parse*, Token*, Token*, Token*, int);
611dce2cbe6Sdrh void sqliteVacuum(Parse*, Token*);
612e17a7e33Sdrh int sqliteGlobCompare(const unsigned char*,const unsigned char*);
613dce2cbe6Sdrh int sqliteLikeCompare(const unsigned char*,const unsigned char*);
614cce7d176Sdrh char *sqliteTableNameFromToken(Token*);
615cce7d176Sdrh int sqliteExprCheck(Parse*, Expr*, int, int*);
616d8bc7086Sdrh int sqliteExprCompare(Expr*, Expr*);
617cce7d176Sdrh int sqliteFuncId(Token*);
618832508b7Sdrh int sqliteExprResolveIds(Parse*, int, IdList*, ExprList*, Expr*);
6192282792aSdrh int sqliteExprAnalyzeAggregates(Parse*, Expr*);
620d8bc7086Sdrh Vdbe *sqliteGetVdbe(Parse*);
621b8ca307eSdrh int sqliteRandomByte(void);
622b8ca307eSdrh int sqliteRandomInteger(void);
6231c92853dSdrh void sqliteBeginTransaction(Parse*, int);
624c4a3c779Sdrh void sqliteCommitTransaction(Parse*);
625c4a3c779Sdrh void sqliteRollbackTransaction(Parse*);
626d1bf3512Sdrh char *sqlite_mprintf(const char *, ...);
6279208643dSdrh int sqliteExprIsConstant(Expr*);
6280ca3e24bSdrh void sqliteGenerateRowDelete(Vdbe*, Table*, int);
6290ca3e24bSdrh void sqliteGenerateRowIndexDelete(Vdbe*, Table*, int, char*);
6300ca3e24bSdrh void sqliteGenerateConstraintChecks(Parse*,Table*,int,char*,int,int,int,int);
631b419a926Sdrh void sqliteCompleteInsertion(Parse*, Table*, int, char*, int, int);
6321c92853dSdrh void sqliteBeginWriteOperation(Parse*);
633663fc63aSdrh void sqliteBeginMultiWriteOperation(Parse*);
6341c92853dSdrh void sqliteEndWriteOperation(Parse*);
635a76b5dfcSdrh void sqliteExprMoveStrings(Expr*, int);
636a76b5dfcSdrh void sqliteExprListMoveStrings(ExprList*, int);
637a76b5dfcSdrh void sqliteSelectMoveStrings(Select*, int);
638ff78bd2fSdrh Expr *sqliteExprDup(Expr*);
639ff78bd2fSdrh ExprList *sqliteExprListDup(ExprList*);
640ff78bd2fSdrh IdList *sqliteIdListDup(IdList*);
641ff78bd2fSdrh Select *sqliteSelectDup(Select*);
6420bce8354Sdrh FuncDef *sqliteFindFunction(sqlite*,const char*,int,int,int);
643dc04c583Sdrh void sqliteRegisterBuildinFunctions(sqlite*);
644