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sqliteInt.h

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00001 /*
00002 ** 2001 September 15
00003 **
00004 ** The author disclaims copyright to this source code.  In place of
00005 ** a legal notice, here is a blessing:
00006 **
00007 **    May you do good and not evil.
00008 **    May you find forgiveness for yourself and forgive others.
00009 **    May you share freely, never taking more than you give.
00010 **
00011 *************************************************************************
00012 ** Internal interface definitions for SQLite.
00013 **
00014 ** @(#) $Id: sqliteInt.h 875674 2008-10-25 07:30:45Z cgilles $
00015 */
00016 
00017 #ifdef HAVE_CONFIG_H
00018 #include "config.h" 
00019 #endif   
00020 
00021 #include "sqlite.h"
00022 #include "hash.h"
00023 #include "parse.h"
00024 #include "btree.h"
00025 #include <stdio.h>
00026 #include <stdlib.h>
00027 #include <string.h>
00028 #include <assert.h>
00029 
00030 /*
00031 ** The maximum number of in-memory pages to use for the main database
00032 ** table and for temporary tables.
00033 */
00034 #define MAX_PAGES   2000
00035 #define TEMP_PAGES   500
00036 
00037 /*
00038 ** If the following macro is set to 1, then NULL values are considered
00039 ** distinct for the SELECT DISTINCT statement and for UNION or EXCEPT
00040 ** compound queries.  No other SQL database engine (among those tested) 
00041 ** works this way except for OCELOT.  But the SQL92 spec implies that
00042 ** this is how things should work.
00043 **
00044 ** If the following macro is set to 0, then NULLs are indistinct for
00045 ** SELECT DISTINCT and for UNION.
00046 */
00047 #define NULL_ALWAYS_DISTINCT 0
00048 
00049 /*
00050 ** If the following macro is set to 1, then NULL values are considered
00051 ** distinct when determining whether or not two entries are the same
00052 ** in a UNIQUE index.  This is the way PostgreSQL, Oracle, DB2, MySQL,
00053 ** OCELOT, and Firebird all work.  The SQL92 spec explicitly says this
00054 ** is the way things are suppose to work.
00055 **
00056 ** If the following macro is set to 0, the NULLs are indistinct for
00057 ** a UNIQUE index.  In this mode, you can only have a single NULL entry
00058 ** for a column declared UNIQUE.  This is the way Informix and SQL Server
00059 ** work.
00060 */
00061 #define NULL_DISTINCT_FOR_UNIQUE 1
00062 
00063 /*
00064 ** The maximum number of attached databases.  This must be at least 2
00065 ** in order to support the main database file (0) and the file used to
00066 ** hold temporary tables (1).  And it must be less than 256 because
00067 ** an unsigned character is used to stored the database index.
00068 */
00069 #define MAX_ATTACHED 10
00070 
00071 /*
00072 ** The next macro is used to determine where TEMP tables and indices
00073 ** are stored.  Possible values:
00074 **
00075 **   0    Always use a temporary files
00076 **   1    Use a file unless overridden by "PRAGMA temp_store"
00077 **   2    Use memory unless overridden by "PRAGMA temp_store"
00078 **   3    Always use memory
00079 */
00080 #ifndef TEMP_STORE
00081 # define TEMP_STORE 1
00082 #endif
00083 
00084 /*
00085 ** When building SQLite for embedded systems where memory is scarce,
00086 ** you can define one or more of the following macros to omit extra
00087 ** features of the library and thus keep the size of the library to
00088 ** a minimum.
00089 */
00090 /* #define SQLITE_OMIT_AUTHORIZATION  1 */
00091 /* #define SQLITE_OMIT_INMEMORYDB     1 */
00092 /* #define SQLITE_OMIT_VACUUM         1 */
00093 /* #define SQLITE_OMIT_DATETIME_FUNCS 1 */
00094 /* #define SQLITE_OMIT_PROGRESS_CALLBACK 1 */
00095 
00096 /*
00097 ** Integers of known sizes.  These typedefs might change for architectures
00098 ** where the sizes very.  Preprocessor macros are available so that the
00099 ** types can be conveniently redefined at compile-type.  Like this:
00100 **
00101 **         cc '-DUINTPTR_TYPE=long long int' ...
00102 */
00103 #ifndef UINT32_TYPE
00104 # define UINT32_TYPE unsigned int
00105 #endif
00106 #ifndef UINT16_TYPE
00107 # define UINT16_TYPE unsigned short int
00108 #endif
00109 #ifndef INT16_TYPE
00110 # define INT16_TYPE short int
00111 #endif
00112 #ifndef UINT8_TYPE
00113 # define UINT8_TYPE unsigned char
00114 #endif
00115 #ifndef INT8_TYPE
00116 # define INT8_TYPE signed char
00117 #endif
00118 #ifndef INTPTR_TYPE
00119 # if SQLITE_PTR_SZ==4
00120 #   define INTPTR_TYPE int
00121 # else
00122 #   define INTPTR_TYPE long long
00123 # endif
00124 #endif
00125 typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
00126 typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
00127 typedef INT16_TYPE i16;            /* 2-byte signed integer */
00128 typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
00129 typedef UINT8_TYPE i8;             /* 1-byte signed integer */
00130 typedef INTPTR_TYPE ptr;           /* Big enough to hold a pointer */
00131 typedef unsigned INTPTR_TYPE uptr; /* Big enough to hold a pointer */
00132 
00133 /*
00134 ** Defer sourcing vdbe.h until after the "u8" typedef is defined.
00135 */
00136 #include "vdbe.h"
00137 
00138 /*
00139 ** Most C compilers these days recognize "long double", don't they?
00140 ** Just in case we encounter one that does not, we will create a macro
00141 ** for long double so that it can be easily changed to just "double".
00142 */
00143 #ifndef LONGDOUBLE_TYPE
00144 # define LONGDOUBLE_TYPE long double
00145 #endif
00146 
00147 /*
00148 ** This macro casts a pointer to an integer.  Useful for doing
00149 ** pointer arithmetic.
00150 */
00151 #define Addr(X)  ((uptr)X)
00152 
00153 /*
00154 ** The maximum number of bytes of data that can be put into a single
00155 ** row of a single table.  The upper bound on this limit is 16777215
00156 ** bytes (or 16MB-1).  We have arbitrarily set the limit to just 1MB
00157 ** here because the overflow page chain is inefficient for really big
00158 ** records and we want to discourage people from thinking that 
00159 ** multi-megabyte records are OK.  If your needs are different, you can
00160 ** change this define and recompile to increase or decrease the record
00161 ** size.
00162 **
00163 ** The 16777198 is computed as follows:  238 bytes of payload on the
00164 ** original pages plus 16448 overflow pages each holding 1020 bytes of
00165 ** data.
00166 */
00167 #define MAX_BYTES_PER_ROW  1048576
00168 /* #define MAX_BYTES_PER_ROW 16777198 */
00169 
00170 /*
00171 ** If memory allocation problems are found, recompile with
00172 **
00173 **      -DMEMORY_DEBUG=1
00174 **
00175 ** to enable some sanity checking on malloc() and free().  To
00176 ** check for memory leaks, recompile with
00177 **
00178 **      -DMEMORY_DEBUG=2
00179 **
00180 ** and a line of text will be written to standard error for
00181 ** each malloc() and free().  This output can be analyzed
00182 ** by an AWK script to determine if there are any leaks.
00183 */
00184 #ifdef MEMORY_DEBUG
00185 # define sqliteMalloc(X)    sqliteMalloc_(X,1,__FILE__,__LINE__)
00186 # define sqliteMallocRaw(X) sqliteMalloc_(X,0,__FILE__,__LINE__)
00187 # define sqliteFree(X)      sqliteFree_(X,__FILE__,__LINE__)
00188 # define sqliteRealloc(X,Y) sqliteRealloc_(X,Y,__FILE__,__LINE__)
00189 # define sqliteStrDup(X)    sqliteStrDup_(X,__FILE__,__LINE__)
00190 # define sqliteStrNDup(X,Y) sqliteStrNDup_(X,Y,__FILE__,__LINE__)
00191   void sqliteStrRealloc(char**);
00192 #else
00193 # define sqliteRealloc_(X,Y) sqliteRealloc(X,Y)
00194 # define sqliteStrRealloc(X)
00195 #endif
00196 
00197 /*
00198 ** This variable gets set if malloc() ever fails.  After it gets set,
00199 ** the SQLite library shuts down permanently.
00200 */
00201 extern int sqlite_malloc_failed;
00202 
00203 /*
00204 ** The following global variables are used for testing and debugging
00205 ** only.  They only work if MEMORY_DEBUG is defined.
00206 */
00207 #ifdef MEMORY_DEBUG
00208 extern int sqlite_nMalloc;       /* Number of sqliteMalloc() calls */
00209 extern int sqlite_nFree;         /* Number of sqliteFree() calls */
00210 extern int sqlite_iMallocFail;   /* Fail sqliteMalloc() after this many calls */
00211 #endif
00212 
00213 /*
00214 ** Name of the master database table.  The master database table
00215 ** is a special table that holds the names and attributes of all
00216 ** user tables and indices.
00217 */
00218 #define MASTER_NAME       "sqlite_master"
00219 #define TEMP_MASTER_NAME  "sqlite_temp_master"
00220 
00221 /*
00222 ** The name of the schema table.
00223 */
00224 #define SCHEMA_TABLE(x)  (x?TEMP_MASTER_NAME:MASTER_NAME)
00225 
00226 /*
00227 ** A convenience macro that returns the number of elements in
00228 ** an array.
00229 */
00230 #define ArraySize(X)    (sizeof(X)/sizeof(X[0]))
00231 
00232 /*
00233 ** Forward references to structures
00234 */
00235 typedef struct Column Column;
00236 typedef struct Table Table;
00237 typedef struct Index Index;
00238 typedef struct Instruction Instruction;
00239 typedef struct Expr Expr;
00240 typedef struct ExprList ExprList;
00241 typedef struct Parse Parse;
00242 typedef struct Token Token;
00243 typedef struct IdList IdList;
00244 typedef struct SrcList SrcList;
00245 typedef struct WhereInfo WhereInfo;
00246 typedef struct WhereLevel WhereLevel;
00247 typedef struct Select Select;
00248 typedef struct AggExpr AggExpr;
00249 typedef struct FuncDef FuncDef;
00250 typedef struct Trigger Trigger;
00251 typedef struct TriggerStep TriggerStep;
00252 typedef struct TriggerStack TriggerStack;
00253 typedef struct FKey FKey;
00254 typedef struct Db Db;
00255 typedef struct AuthContext AuthContext;
00256 
00257 /*
00258 ** Each database file to be accessed by the system is an instance
00259 ** of the following structure.  There are normally two of these structures
00260 ** in the sqlite.aDb[] array.  aDb[0] is the main database file and
00261 ** aDb[1] is the database file used to hold temporary tables.  Additional
00262 ** databases may be attached.
00263 */
00264 struct Db {
00265   char *zName;         /* Name of this database */
00266   Btree *pBt;          /* The B*Tree structure for this database file */
00267   int schema_cookie;   /* Database schema version number for this file */
00268   Hash tblHash;        /* All tables indexed by name */
00269   Hash idxHash;        /* All (named) indices indexed by name */
00270   Hash trigHash;       /* All triggers indexed by name */
00271   Hash aFKey;          /* Foreign keys indexed by to-table */
00272   u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
00273   u16 flags;           /* Flags associated with this database */
00274   void *pAux;          /* Auxiliary data.  Usually NULL */
00275   void (*xFreeAux)(void*);  /* Routine to free pAux */
00276 };
00277 
00278 /*
00279 ** These macros can be used to test, set, or clear bits in the 
00280 ** Db.flags field.
00281 */
00282 #define DbHasProperty(D,I,P)     (((D)->aDb[I].flags&(P))==(P))
00283 #define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].flags&(P))!=0)
00284 #define DbSetProperty(D,I,P)     (D)->aDb[I].flags|=(P)
00285 #define DbClearProperty(D,I,P)   (D)->aDb[I].flags&=~(P)
00286 
00287 /*
00288 ** Allowed values for the DB.flags field.
00289 **
00290 ** The DB_Locked flag is set when the first OP_Transaction or OP_Checkpoint
00291 ** opcode is emitted for a database.  This prevents multiple occurances
00292 ** of those opcodes for the same database in the same program.  Similarly,
00293 ** the DB_Cookie flag is set when the OP_VerifyCookie opcode is emitted,
00294 ** and prevents duplicate OP_VerifyCookies from taking up space and slowing
00295 ** down execution.
00296 **
00297 ** The DB_SchemaLoaded flag is set after the database schema has been
00298 ** read into internal hash tables.
00299 **
00300 ** DB_UnresetViews means that one or more views have column names that
00301 ** have been filled out.  If the schema changes, these column names might
00302 ** changes and so the view will need to be reset.
00303 */
00304 #define DB_Locked          0x0001  /* OP_Transaction opcode has been emitted */
00305 #define DB_Cookie          0x0002  /* OP_VerifyCookie opcode has been emiited */
00306 #define DB_SchemaLoaded    0x0004  /* The schema has been loaded */
00307 #define DB_UnresetViews    0x0008  /* Some views have defined column names */
00308 
00309 
00310 /*
00311 ** Each database is an instance of the following structure.
00312 **
00313 ** The sqlite.file_format is initialized by the database file
00314 ** and helps determines how the data in the database file is
00315 ** represented.  This field allows newer versions of the library
00316 ** to read and write older databases.  The various file formats
00317 ** are as follows:
00318 **
00319 **     file_format==1    Version 2.1.0.
00320 **     file_format==2    Version 2.2.0. Add support for INTEGER PRIMARY KEY.
00321 **     file_format==3    Version 2.6.0. Fix empty-string index bug.
00322 **     file_format==4    Version 2.7.0. Add support for separate numeric and
00323 **                       text datatypes.
00324 **
00325 ** The sqlite.temp_store determines where temporary database files
00326 ** are stored.  If 1, then a file is created to hold those tables.  If
00327 ** 2, then they are held in memory.  0 means use the default value in
00328 ** the TEMP_STORE macro.
00329 **
00330 ** The sqlite.lastRowid records the last insert rowid generated by an
00331 ** insert statement.  Inserts on views do not affect its value.  Each
00332 ** trigger has its own context, so that lastRowid can be updated inside
00333 ** triggers as usual.  The previous value will be restored once the trigger
00334 ** exits.  Upon entering a before or instead of trigger, lastRowid is no
00335 ** longer (since after version 2.8.12) reset to -1.
00336 **
00337 ** The sqlite.nChange does not count changes within triggers and keeps no
00338 ** context.  It is reset at start of sqlite_exec.
00339 ** The sqlite.lsChange represents the number of changes made by the last
00340 ** insert, update, or delete statement.  It remains constant throughout the
00341 ** length of a statement and is then updated by OP_SetCounts.  It keeps a
00342 ** context stack just like lastRowid so that the count of changes
00343 ** within a trigger is not seen outside the trigger.  Changes to views do not
00344 ** affect the value of lsChange.
00345 ** The sqlite.csChange keeps track of the number of current changes (since
00346 ** the last statement) and is used to update sqlite_lsChange.
00347 */
00348 struct sqlite {
00349   int nDb;                      /* Number of backends currently in use */
00350   Db *aDb;                      /* All backends */
00351   Db aDbStatic[2];              /* Static space for the 2 default backends */
00352   int flags;                    /* Miscellanous flags. See below */
00353   u8 file_format;               /* What file format version is this database? */
00354   u8 safety_level;              /* How aggressive at synching data to disk */
00355   u8 want_to_close;             /* Close after all VDBEs are deallocated */
00356   u8 temp_store;                /* 1=file, 2=memory, 0=compile-time default */
00357   u8 onError;                   /* Default conflict algorithm */
00358   int next_cookie;              /* Next value of aDb[0].schema_cookie */
00359   int cache_size;               /* Number of pages to use in the cache */
00360   int nTable;                   /* Number of tables in the database */
00361   void *pBusyArg;               /* 1st Argument to the busy callback */
00362   int (*xBusyCallback)(void *,const char*,int);  /* The busy callback */
00363   void *pCommitArg;             /* Argument to xCommitCallback() */   
00364   int (*xCommitCallback)(void*);/* Invoked at every commit. */
00365   Hash aFunc;                   /* All functions that can be in SQL exprs */
00366   int lastRowid;                /* ROWID of most recent insert (see above) */
00367   int priorNewRowid;            /* Last randomly generated ROWID */
00368   int magic;                    /* Magic number for detect library misuse */
00369   int nChange;                  /* Number of rows changed (see above) */
00370   int lsChange;                 /* Last statement change count (see above) */
00371   int csChange;                 /* Current statement change count (see above) */
00372   struct sqliteInitInfo {       /* Information used during initialization */
00373     int iDb;                       /* When back is being initialized */
00374     int newTnum;                   /* Rootpage of table being initialized */
00375     u8 busy;                       /* TRUE if currently initializing */
00376   } init;
00377   struct Vdbe *pVdbe;           /* List of active virtual machines */
00378   void (*xTrace)(void*,const char*);     /* Trace function */
00379   void *pTraceArg;                       /* Argument to the trace function */
00380 #ifndef SQLITE_OMIT_AUTHORIZATION
00381   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*);
00382                                 /* Access authorization function */
00383   void *pAuthArg;               /* 1st argument to the access auth function */
00384 #endif
00385 #ifndef SQLITE_OMIT_PROGRESS_CALLBACK
00386   int (*xProgress)(void *);     /* The progress callback */
00387   void *pProgressArg;           /* Argument to the progress callback */
00388   int nProgressOps;             /* Number of opcodes for progress callback */
00389 #endif
00390 };
00391 
00392 /*
00393 ** Possible values for the sqlite.flags and or Db.flags fields.
00394 **
00395 ** On sqlite.flags, the SQLITE_InTrans value means that we have
00396 ** executed a BEGIN.  On Db.flags, SQLITE_InTrans means a statement
00397 ** transaction is active on that particular database file.
00398 */
00399 #define SQLITE_VdbeTrace      0x00000001  /* True to trace VDBE execution */
00400 #define SQLITE_Initialized    0x00000002  /* True after initialization */
00401 #define SQLITE_Interrupt      0x00000004  /* Cancel current operation */
00402 #define SQLITE_InTrans        0x00000008  /* True if in a transaction */
00403 #define SQLITE_InternChanges  0x00000010  /* Uncommitted Hash table changes */
00404 #define SQLITE_FullColNames   0x00000020  /* Show full column names on SELECT */
00405 #define SQLITE_ShortColNames  0x00000040  /* Show short columns names */
00406 #define SQLITE_CountRows      0x00000080  /* Count rows changed by INSERT, */
00407                                           /*   DELETE, or UPDATE and return */
00408                                           /*   the count using a callback. */
00409 #define SQLITE_NullCallback   0x00000100  /* Invoke the callback once if the */
00410                                           /*   result set is empty */
00411 #define SQLITE_ReportTypes    0x00000200  /* Include information on datatypes */
00412                                           /*   in 4th argument of callback */
00413 
00414 /*
00415 ** Possible values for the sqlite.magic field.
00416 ** The numbers are obtained at random and have no special meaning, other
00417 ** than being distinct from one another.
00418 */
00419 #define SQLITE_MAGIC_OPEN     0xa029a697  /* Database is open */
00420 #define SQLITE_MAGIC_CLOSED   0x9f3c2d33  /* Database is closed */
00421 #define SQLITE_MAGIC_BUSY     0xf03b7906  /* Database currently in use */
00422 #define SQLITE_MAGIC_ERROR    0xb5357930  /* An SQLITE_MISUSE error occurred */
00423 
00424 /*
00425 ** Each SQL function is defined by an instance of the following
00426 ** structure.  A pointer to this structure is stored in the sqlite.aFunc
00427 ** hash table.  When multiple functions have the same name, the hash table
00428 ** points to a linked list of these structures.
00429 */
00430 struct FuncDef {
00431   void (*xFunc)(sqlite_func*,int,const char**);  /* Regular function */
00432   void (*xStep)(sqlite_func*,int,const char**);  /* Aggregate function step */
00433   void (*xFinalize)(sqlite_func*);           /* Aggregate function finializer */
00434   signed char nArg;         /* Number of arguments.  -1 means unlimited */
00435   signed char dataType;     /* Arg that determines datatype.  -1=NUMERIC, */
00436                             /* -2=TEXT. -3=SQLITE_ARGS */
00437   u8 includeTypes;          /* Add datatypes to args of xFunc and xStep */
00438   void *pUserData;          /* User data parameter */
00439   FuncDef *pNext;           /* Next function with same name */
00440 };
00441 
00442 /*
00443 ** information about each column of an SQL table is held in an instance
00444 ** of this structure.
00445 */
00446 struct Column {
00447   char *zName;     /* Name of this column */
00448   char *zDflt;     /* Default value of this column */
00449   char *zType;     /* Data type for this column */
00450   u8 notNull;      /* True if there is a NOT NULL constraint */
00451   u8 isPrimKey;    /* True if this column is part of the PRIMARY KEY */
00452   u8 sortOrder;    /* Some combination of SQLITE_SO_... values */
00453   u8 dottedName;   /* True if zName contains a "." character */
00454 };
00455 
00456 /*
00457 ** The allowed sort orders.
00458 **
00459 ** The TEXT and NUM values use bits that do not overlap with DESC and ASC.
00460 ** That way the two can be combined into a single number.
00461 */
00462 #define SQLITE_SO_UNK       0  /* Use the default collating type.  (SCT_NUM) */
00463 #define SQLITE_SO_TEXT      2  /* Sort using memcmp() */
00464 #define SQLITE_SO_NUM       4  /* Sort using sqliteCompare() */
00465 #define SQLITE_SO_TYPEMASK  6  /* Mask to extract the collating sequence */
00466 #define SQLITE_SO_ASC       0  /* Sort in ascending order */
00467 #define SQLITE_SO_DESC      1  /* Sort in descending order */
00468 #define SQLITE_SO_DIRMASK   1  /* Mask to extract the sort direction */
00469 
00470 /*
00471 ** Each SQL table is represented in memory by an instance of the
00472 ** following structure.
00473 **
00474 ** Table.zName is the name of the table.  The case of the original
00475 ** CREATE TABLE statement is stored, but case is not significant for
00476 ** comparisons.
00477 **
00478 ** Table.nCol is the number of columns in this table.  Table.aCol is a
00479 ** pointer to an array of Column structures, one for each column.
00480 **
00481 ** If the table has an INTEGER PRIMARY KEY, then Table.iPKey is the index of
00482 ** the column that is that key.   Otherwise Table.iPKey is negative.  Note
00483 ** that the datatype of the PRIMARY KEY must be INTEGER for this field to
00484 ** be set.  An INTEGER PRIMARY KEY is used as the rowid for each row of
00485 ** the table.  If a table has no INTEGER PRIMARY KEY, then a random rowid
00486 ** is generated for each row of the table.  Table.hasPrimKey is true if
00487 ** the table has any PRIMARY KEY, INTEGER or otherwise.
00488 **
00489 ** Table.tnum is the page number for the root BTree page of the table in the
00490 ** database file.  If Table.iDb is the index of the database table backend
00491 ** in sqlite.aDb[].  0 is for the main database and 1 is for the file that
00492 ** holds temporary tables and indices.  If Table.isTransient
00493 ** is true, then the table is stored in a file that is automatically deleted
00494 ** when the VDBE cursor to the table is closed.  In this case Table.tnum 
00495 ** refers VDBE cursor number that holds the table open, not to the root
00496 ** page number.  Transient tables are used to hold the results of a
00497 ** sub-query that appears instead of a real table name in the FROM clause 
00498 ** of a SELECT statement.
00499 */
00500 struct Table {
00501   char *zName;     /* Name of the table */
00502   int nCol;        /* Number of columns in this table */
00503   Column *aCol;    /* Information about each column */
00504   int iPKey;       /* If not less then 0, use aCol[iPKey] as the primary key */
00505   Index *pIndex;   /* List of SQL indexes on this table. */
00506   int tnum;        /* Root BTree node for this table (see note above) */
00507   Select *pSelect; /* NULL for tables.  Points to definition if a view. */
00508   u8 readOnly;     /* True if this table should not be written by the user */
00509   u8 iDb;          /* Index into sqlite.aDb[] of the backend for this table */
00510   u8 isTransient;  /* True if automatically deleted when VDBE finishes */
00511   u8 hasPrimKey;   /* True if there exists a primary key */
00512   u8 keyConf;      /* What to do in case of uniqueness conflict on iPKey */
00513   Trigger *pTrigger; /* List of SQL triggers on this table */
00514   FKey *pFKey;       /* Linked list of all foreign keys in this table */
00515 };
00516 
00517 /*
00518 ** Each foreign key constraint is an instance of the following structure.
00519 **
00520 ** A foreign key is associated with two tables.  The "from" table is
00521 ** the table that contains the REFERENCES clause that creates the foreign
00522 ** key.  The "to" table is the table that is named in the REFERENCES clause.
00523 ** Consider this example:
00524 **
00525 **     CREATE TABLE ex1(
00526 **       a INTEGER PRIMARY KEY,
00527 **       b INTEGER CONSTRAINT fk1 REFERENCES ex2(x)
00528 **     );
00529 **
00530 ** For foreign key "fk1", the from-table is "ex1" and the to-table is "ex2".
00531 **
00532 ** Each REFERENCES clause generates an instance of the following structure
00533 ** which is attached to the from-table.  The to-table need not exist when
00534 ** the from-table is created.  The existance of the to-table is not checked
00535 ** until an attempt is made to insert data into the from-table.
00536 **
00537 ** The sqlite.aFKey hash table stores pointers to this structure
00538 ** given the name of a to-table.  For each to-table, all foreign keys
00539 ** associated with that table are on a linked list using the FKey.pNextTo
00540 ** field.
00541 */
00542 struct FKey {
00543   Table *pFrom;     /* The table that constains the REFERENCES clause */
00544   FKey *pNextFrom;  /* Next foreign key in pFrom */
00545   char *zTo;        /* Name of table that the key points to */
00546   FKey *pNextTo;    /* Next foreign key that points to zTo */
00547   int nCol;         /* Number of columns in this key */
00548   struct sColMap {  /* Mapping of columns in pFrom to columns in zTo */
00549     int iFrom;         /* Index of column in pFrom */
00550     char *zCol;        /* Name of column in zTo.  If 0 use PRIMARY KEY */
00551   } *aCol;          /* One entry for each of nCol column s */
00552   u8 isDeferred;    /* True if constraint checking is deferred till COMMIT */
00553   u8 updateConf;    /* How to resolve conflicts that occur on UPDATE */
00554   u8 deleteConf;    /* How to resolve conflicts that occur on DELETE */
00555   u8 insertConf;    /* How to resolve conflicts that occur on INSERT */
00556 };
00557 
00558 /*
00559 ** SQLite supports many different ways to resolve a contraint
00560 ** error.  ROLLBACK processing means that a constraint violation
00561 ** causes the operation in process to fail and for the current transaction
00562 ** to be rolled back.  ABORT processing means the operation in process
00563 ** fails and any prior changes from that one operation are backed out,
00564 ** but the transaction is not rolled back.  FAIL processing means that
00565 ** the operation in progress stops and returns an error code.  But prior
00566 ** changes due to the same operation are not backed out and no rollback
00567 ** occurs.  IGNORE means that the particular row that caused the constraint
00568 ** error is not inserted or updated.  Processing continues and no error
00569 ** is returned.  REPLACE means that preexisting database rows that caused
00570 ** a UNIQUE constraint violation are removed so that the new insert or
00571 ** update can proceed.  Processing continues and no error is reported.
00572 **
00573 ** RESTRICT, SETNULL, and CASCADE actions apply only to foreign keys.
00574 ** RESTRICT is the same as ABORT for IMMEDIATE foreign keys and the
00575 ** same as ROLLBACK for DEFERRED keys.  SETNULL means that the foreign
00576 ** key is set to NULL.  CASCADE means that a DELETE or UPDATE of the
00577 ** referenced table row is propagated into the row that holds the
00578 ** foreign key.
00579 ** 
00580 ** The following symbolic values are used to record which type
00581 ** of action to take.
00582 */
00583 #define OE_None     0   /* There is no constraint to check */
00584 #define OE_Rollback 1   /* Fail the operation and rollback the transaction */
00585 #define OE_Abort    2   /* Back out changes but do no rollback transaction */
00586 #define OE_Fail     3   /* Stop the operation but leave all prior changes */
00587 #define OE_Ignore   4   /* Ignore the error. Do not do the INSERT or UPDATE */
00588 #define OE_Replace  5   /* Delete existing record, then do INSERT or UPDATE */
00589 
00590 #define OE_Restrict 6   /* OE_Abort for IMMEDIATE, OE_Rollback for DEFERRED */
00591 #define OE_SetNull  7   /* Set the foreign key value to NULL */
00592 #define OE_SetDflt  8   /* Set the foreign key value to its default */
00593 #define OE_Cascade  9   /* Cascade the changes */
00594 
00595 #define OE_Default  99  /* Do whatever the default action is */
00596 
00597 /*
00598 ** Each SQL index is represented in memory by an
00599 ** instance of the following structure.
00600 **
00601 ** The columns of the table that are to be indexed are described
00602 ** by the aiColumn[] field of this structure.  For example, suppose
00603 ** we have the following table and index:
00604 **
00605 **     CREATE TABLE Ex1(c1 int, c2 int, c3 text);
00606 **     CREATE INDEX Ex2 ON Ex1(c3,c1);
00607 **
00608 ** In the Table structure describing Ex1, nCol==3 because there are
00609 ** three columns in the table.  In the Index structure describing
00610 ** Ex2, nColumn==2 since 2 of the 3 columns of Ex1 are indexed.
00611 ** The value of aiColumn is {2, 0}.  aiColumn[0]==2 because the 
00612 ** first column to be indexed (c3) has an index of 2 in Ex1.aCol[].
00613 ** The second column to be indexed (c1) has an index of 0 in
00614 ** Ex1.aCol[], hence Ex2.aiColumn[1]==0.
00615 **
00616 ** The Index.onError field determines whether or not the indexed columns
00617 ** must be unique and what to do if they are not.  When Index.onError=OE_None,
00618 ** it means this is not a unique index.  Otherwise it is a unique index
00619 ** and the value of Index.onError indicate the which conflict resolution 
00620 ** algorithm to employ whenever an attempt is made to insert a non-unique
00621 ** element.
00622 */
00623 struct Index {
00624   char *zName;     /* Name of this index */
00625   int nColumn;     /* Number of columns in the table used by this index */
00626   int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
00627   Table *pTable;   /* The SQL table being indexed */
00628   int tnum;        /* Page containing root of this index in database file */
00629   u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
00630   u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
00631   u8 iDb;          /* Index in sqlite.aDb[] of where this index is stored */
00632   Index *pNext;    /* The next index associated with the same table */
00633 };
00634 
00635 /*
00636 ** Each token coming out of the lexer is an instance of
00637 ** this structure.  Tokens are also used as part of an expression.
00638 **
00639 ** Note if Token.z==0 then Token.dyn and Token.n are undefined and
00640 ** may contain random values.  Do not make any assuptions about Token.dyn
00641 ** and Token.n when Token.z==0.
00642 */
00643 struct Token {
00644   const char *z;      /* Text of the token.  Not NULL-terminated! */
00645   unsigned dyn  : 1;  /* True for malloced memory, false for static */
00646   unsigned n    : 31; /* Number of characters in this token */
00647 };
00648 
00649 /*
00650 ** Each node of an expression in the parse tree is an instance
00651 ** of this structure.
00652 **
00653 ** Expr.op is the opcode.  The integer parser token codes are reused
00654 ** as opcodes here.  For example, the parser defines TK_GE to be an integer
00655 ** code representing the ">=" operator.  This same integer code is reused
00656 ** to represent the greater-than-or-equal-to operator in the expression
00657 ** tree.
00658 **
00659 ** Expr.pRight and Expr.pLeft are subexpressions.  Expr.pList is a list
00660 ** of argument if the expression is a function.
00661 **
00662 ** Expr.token is the operator token for this node.  For some expressions
00663 ** that have subexpressions, Expr.token can be the complete text that gave
00664 ** rise to the Expr.  In the latter case, the token is marked as being
00665 ** a compound token.
00666 **
00667 ** An expression of the form ID or ID.ID refers to a column in a table.
00668 ** For such expressions, Expr.op is set to TK_COLUMN and Expr.iTable is
00669 ** the integer cursor number of a VDBE cursor pointing to that table and
00670 ** Expr.iColumn is the column number for the specific column.  If the
00671 ** expression is used as a result in an aggregate SELECT, then the
00672 ** value is also stored in the Expr.iAgg column in the aggregate so that
00673 ** it can be accessed after all aggregates are computed.
00674 **
00675 ** If the expression is a function, the Expr.iTable is an integer code
00676 ** representing which function.  If the expression is an unbound variable
00677 ** marker (a question mark character '?' in the original SQL) then the
00678 ** Expr.iTable holds the index number for that variable.
00679 **
00680 ** The Expr.pSelect field points to a SELECT statement.  The SELECT might
00681 ** be the right operand of an IN operator.  Or, if a scalar SELECT appears
00682 ** in an expression the opcode is TK_SELECT and Expr.pSelect is the only
00683 ** operand.
00684 */
00685 struct Expr {
00686   u8 op;                 /* Operation performed by this node */
00687   u8 dataType;           /* Either SQLITE_SO_TEXT or SQLITE_SO_NUM */
00688   u8 iDb;                /* Database referenced by this expression */
00689   u8 flags;              /* Various flags.  See below */
00690   Expr *pLeft, *pRight;  /* Left and right subnodes */
00691   ExprList *pList;       /* A list of expressions used as function arguments
00692                          ** or in "<expr> IN (<expr-list)" */
00693   Token token;           /* An operand token */
00694   Token span;            /* Complete text of the expression */
00695   int iTable, iColumn;   /* When op==TK_COLUMN, then this expr node means the
00696                          ** iColumn-th field of the iTable-th table. */
00697   int iAgg;              /* When op==TK_COLUMN and pParse->useAgg==TRUE, pull
00698                          ** result from the iAgg-th element of the aggregator */
00699   Select *pSelect;       /* When the expression is a sub-select.  Also the
00700                          ** right side of "<expr> IN (<select>)" */
00701 };
00702 
00703 /*
00704 ** The following are the meanings of bits in the Expr.flags field.
00705 */
00706 #define EP_FromJoin     0x0001  /* Originated in ON or USING clause of a join */
00707 
00708 /*
00709 ** These macros can be used to test, set, or clear bits in the 
00710 ** Expr.flags field.
00711 */
00712 #define ExprHasProperty(E,P)     (((E)->flags&(P))==(P))
00713 #define ExprHasAnyProperty(E,P)  (((E)->flags&(P))!=0)
00714 #define ExprSetProperty(E,P)     (E)->flags|=(P)
00715 #define ExprClearProperty(E,P)   (E)->flags&=~(P)
00716 
00717 /*
00718 ** A list of expressions.  Each expression may optionally have a
00719 ** name.  An expr/name combination can be used in several ways, such
00720 ** as the list of "expr AS ID" fields following a "SELECT" or in the
00721 ** list of "ID = expr" items in an UPDATE.  A list of expressions can
00722 ** also be used as the argument to a function, in which case the a.zName
00723 ** field is not used.
00724 */
00725 struct ExprList {
00726   int nExpr;             /* Number of expressions on the list */
00727   int nAlloc;            /* Number of entries allocated below */
00728   struct ExprList_item {
00729     Expr *pExpr;           /* The list of expressions */
00730     char *zName;           /* Token associated with this expression */
00731     u8 sortOrder;          /* 1 for DESC or 0 for ASC */
00732     u8 isAgg;              /* True if this is an aggregate like count(*) */
00733     u8 done;               /* A flag to indicate when processing is finished */
00734   } *a;                  /* One entry for each expression */
00735 };
00736 
00737 /*
00738 ** An instance of this structure can hold a simple list of identifiers,
00739 ** such as the list "a,b,c" in the following statements:
00740 **
00741 **      INSERT INTO t(a,b,c) VALUES ...;
00742 **      CREATE INDEX idx ON t(a,b,c);
00743 **      CREATE TRIGGER trig BEFORE UPDATE ON t(a,b,c) ...;
00744 **
00745 ** The IdList.a.idx field is used when the IdList represents the list of
00746 ** column names after a table name in an INSERT statement.  In the statement
00747 **
00748 **     INSERT INTO t(a,b,c) ...
00749 **
00750 ** If "a" is the k-th column of table "t", then IdList.a[0].idx==k.
00751 */
00752 struct IdList {
00753   int nId;         /* Number of identifiers on the list */
00754   int nAlloc;      /* Number of entries allocated for a[] below */
00755   struct IdList_item {
00756     char *zName;      /* Name of the identifier */
00757     int idx;          /* Index in some Table.aCol[] of a column named zName */
00758   } *a;
00759 };
00760 
00761 /*
00762 ** The following structure describes the FROM clause of a SELECT statement.
00763 ** Each table or subquery in the FROM clause is a separate element of
00764 ** the SrcList.a[] array.
00765 **
00766 ** With the addition of multiple database support, the following structure
00767 ** can also be used to describe a particular table such as the table that
00768 ** is modified by an INSERT, DELETE, or UPDATE statement.  In standard SQL,
00769 ** such a table must be a simple name: ID.  But in SQLite, the table can
00770 ** now be identified by a database name, a dot, then the table name: ID.ID.
00771 */
00772 struct SrcList {
00773   i16 nSrc;        /* Number of tables or subqueries in the FROM clause */
00774   i16 nAlloc;      /* Number of entries allocated in a[] below */
00775   struct SrcList_item {
00776     char *zDatabase;  /* Name of database holding this table */
00777     char *zName;      /* Name of the table */
00778     char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
00779     Table *pTab;      /* An SQL table corresponding to zName */
00780     Select *pSelect;  /* A SELECT statement used in place of a table name */
00781     int jointype;     /* Type of join between this table and the next */
00782     int iCursor;      /* The VDBE cursor number used to access this table */
00783     Expr *pOn;        /* The ON clause of a join */
00784     IdList *pUsing;   /* The USING clause of a join */
00785   } a[1];             /* One entry for each identifier on the list */
00786 };
00787 
00788 /*
00789 ** Permitted values of the SrcList.a.jointype field
00790 */
00791 #define JT_INNER     0x0001    /* Any kind of inner or cross join */
00792 #define JT_NATURAL   0x0002    /* True for a "natural" join */
00793 #define JT_LEFT      0x0004    /* Left outer join */
00794 #define JT_RIGHT     0x0008    /* Right outer join */
00795 #define JT_OUTER     0x0010    /* The "OUTER" keyword is present */
00796 #define JT_ERROR     0x0020    /* unknown or unsupported join type */
00797 
00798 /*
00799 ** For each nested loop in a WHERE clause implementation, the WhereInfo
00800 ** structure contains a single instance of this structure.  This structure
00801 ** is intended to be private the the where.c module and should not be
00802 ** access or modified by other modules.
00803 */
00804 struct WhereLevel {
00805   int iMem;            /* Memory cell used by this level */
00806   Index *pIdx;         /* Index used */
00807   int iCur;            /* Cursor number used for this index */
00808   int score;           /* How well this indexed scored */
00809   int brk;             /* Jump here to break out of the loop */
00810   int cont;            /* Jump here to continue with the next loop cycle */
00811   int op, p1, p2;      /* Opcode used to terminate the loop */
00812   int iLeftJoin;       /* Memory cell used to implement LEFT OUTER JOIN */
00813   int top;             /* First instruction of interior of the loop */
00814   int inOp, inP1, inP2;/* Opcode used to implement an IN operator */
00815   int bRev;            /* Do the scan in the reverse direction */
00816 };
00817 
00818 /*
00819 ** The WHERE clause processing routine has two halves.  The
00820 ** first part does the start of the WHERE loop and the second
00821 ** half does the tail of the WHERE loop.  An instance of
00822 ** this structure is returned by the first half and passed
00823 ** into the second half to give some continuity.
00824 */
00825 struct WhereInfo {
00826   Parse *pParse;
00827   SrcList *pTabList;   /* List of tables in the join */
00828   int iContinue;       /* Jump here to continue with next record */
00829   int iBreak;          /* Jump here to break out of the loop */
00830   int nLevel;          /* Number of nested loop */
00831   int savedNTab;       /* Value of pParse->nTab before WhereBegin() */
00832   int peakNTab;        /* Value of pParse->nTab after WhereBegin() */
00833   WhereLevel a[1];     /* Information about each nest loop in the WHERE */
00834 };
00835 
00836 /*
00837 ** An instance of the following structure contains all information
00838 ** needed to generate code for a single SELECT statement.
00839 **
00840 ** The zSelect field is used when the Select structure must be persistent.
00841 ** Normally, the expression tree points to tokens in the original input
00842 ** string that encodes the select.  But if the Select structure must live
00843 ** longer than its input string (for example when it is used to describe
00844 ** a VIEW) we have to make a copy of the input string so that the nodes
00845 ** of the expression tree will have something to point to.  zSelect is used
00846 ** to hold that copy.
00847 **
00848 ** nLimit is set to -1 if there is no LIMIT clause.  nOffset is set to 0.
00849 ** If there is a LIMIT clause, the parser sets nLimit to the value of the
00850 ** limit and nOffset to the value of the offset (or 0 if there is not
00851 ** offset).  But later on, nLimit and nOffset become the memory locations
00852 ** in the VDBE that record the limit and offset counters.
00853 */
00854 struct Select {
00855   ExprList *pEList;      /* The fields of the result */
00856   u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
00857   u8 isDistinct;         /* True if the DISTINCT keyword is present */
00858   SrcList *pSrc;         /* The FROM clause */
00859   Expr *pWhere;          /* The WHERE clause */
00860   ExprList *pGroupBy;    /* The GROUP BY clause */
00861   Expr *pHaving;         /* The HAVING clause */
00862   ExprList *pOrderBy;    /* The ORDER BY clause */
00863   Select *pPrior;        /* Prior select in a compound select statement */
00864   int nLimit, nOffset;   /* LIMIT and OFFSET values.  -1 means not used */
00865   int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
00866   char *zSelect;         /* Complete text of the SELECT command */
00867 };
00868 
00869 /*
00870 ** The results of a select can be distributed in several ways.
00871 */
00872 #define SRT_Callback     1  /* Invoke a callback with each row of result */
00873 #define SRT_Mem          2  /* Store result in a memory cell */
00874 #define SRT_Set          3  /* Store result as unique keys in a table */
00875 #define SRT_Union        5  /* Store result as keys in a table */
00876 #define SRT_Except       6  /* Remove result from a UNION table */
00877 #define SRT_Table        7  /* Store result as data with a unique key */
00878 #define SRT_TempTable    8  /* Store result in a trasient table */
00879 #define SRT_Discard      9  /* Do not save the results anywhere */
00880 #define SRT_Sorter      10  /* Store results in the sorter */
00881 #define SRT_Subroutine  11  /* Call a subroutine to handle results */
00882 
00883 /*
00884 ** When a SELECT uses aggregate functions (like "count(*)" or "avg(f1)")
00885 ** we have to do some additional analysis of expressions.  An instance
00886 ** of the following structure holds information about a single subexpression
00887 ** somewhere in the SELECT statement.  An array of these structures holds
00888 ** all the information we need to generate code for aggregate
00889 ** expressions.
00890 **
00891 ** Note that when analyzing a SELECT containing aggregates, both
00892 ** non-aggregate field variables and aggregate functions are stored
00893 ** in the AggExpr array of the Parser structure.
00894 **
00895 ** The pExpr field points to an expression that is part of either the
00896 ** field list, the GROUP BY clause, the HAVING clause or the ORDER BY
00897 ** clause.  The expression will be freed when those clauses are cleaned
00898 ** up.  Do not try to delete the expression attached to AggExpr.pExpr.
00899 **
00900 ** If AggExpr.pExpr==0, that means the expression is "count(*)".
00901 */
00902 struct AggExpr {
00903   int isAgg;        /* if TRUE contains an aggregate function */
00904   Expr *pExpr;      /* The expression */
00905   FuncDef *pFunc;   /* Information about the aggregate function */
00906 };
00907 
00908 /*
00909 ** An SQL parser context.  A copy of this structure is passed through
00910 ** the parser and down into all the parser action routine in order to
00911 ** carry around information that is global to the entire parse.
00912 */
00913 struct Parse {
00914   sqlite *db;          /* The main database structure */
00915   int rc;              /* Return code from execution */
00916   char *zErrMsg;       /* An error message */
00917   Token sErrToken;     /* The token at which the error occurred */
00918   Token sFirstToken;   /* The first token parsed */
00919   Token sLastToken;    /* The last token parsed */
00920   const char *zTail;   /* All SQL text past the last semicolon parsed */
00921   Table *pNewTable;    /* A table being constructed by CREATE TABLE */
00922   Vdbe *pVdbe;         /* An engine for executing database bytecode */
00923   u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
00924   u8 explain;          /* True if the EXPLAIN flag is found on the query */
00925   u8 nameClash;        /* A permanent table name clashes with temp table name */
00926   u8 useAgg;           /* If true, extract field values from the aggregator
00927                        ** while generating expressions.  Normally false */
00928   int nErr;            /* Number of errors seen */
00929   int nTab;            /* Number of previously allocated VDBE cursors */
00930   int nMem;            /* Number of memory cells used so far */
00931   int nSet;            /* Number of sets used so far */
00932   int nAgg;            /* Number of aggregate expressions */
00933   int nVar;            /* Number of '?' variables seen in the SQL so far */
00934   AggExpr *aAgg;       /* An array of aggregate expressions */
00935   const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
00936   Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
00937   TriggerStack *trigStack;  /* Trigger actions being coded */
00938 };
00939 
00940 /*
00941 ** An instance of the following structure can be declared on a stack and used
00942 ** to save the Parse.zAuthContext value so that it can be restored later.
00943 */
00944 struct AuthContext {
00945   const char *zAuthContext;   /* Put saved Parse.zAuthContext here */
00946   Parse *pParse;              /* The Parse structure */
00947 };
00948 
00949 /*
00950 ** Bitfield flags for P2 value in OP_PutIntKey and OP_Delete
00951 */
00952 #define OPFLAG_NCHANGE   1    /* Set to update db->nChange */
00953 #define OPFLAG_LASTROWID 2    /* Set to update db->lastRowid */
00954 #define OPFLAG_CSCHANGE  4    /* Set to update db->csChange */
00955 
00956 /*
00957  * Each trigger present in the database schema is stored as an instance of
00958  * struct Trigger. 
00959  *
00960  * Pointers to instances of struct Trigger are stored in two ways.
00961  * 1. In the "trigHash" hash table (part of the sqlite* that represents the 
00962  *    database). This allows Trigger structures to be retrieved by name.
00963  * 2. All triggers associated with a single table form a linked list, using the
00964  *    pNext member of struct Trigger. A pointer to the first element of the
00965  *    linked list is stored as the "pTrigger" member of the associated
00966  *    struct Table.
00967  *
00968  * The "step_list" member points to the first element of a linked list
00969  * containing the SQL statements specified as the trigger program.
00970  */
00971 struct Trigger {
00972   char *name;             /* The name of the trigger                        */
00973   char *table;            /* The table or view to which the trigger applies */
00974   u8 iDb;                 /* Database containing this trigger               */
00975   u8 iTabDb;              /* Database containing Trigger.table              */
00976   u8 op;                  /* One of TK_DELETE, TK_UPDATE, TK_INSERT         */
00977   u8 tr_tm;               /* One of TK_BEFORE, TK_AFTER */
00978   Expr *pWhen;            /* The WHEN clause of the expresion (may be NULL) */
00979   IdList *pColumns;       /* If this is an UPDATE OF <column-list> trigger,
00980                              the <column-list> is stored here */
00981   int foreach;            /* One of TK_ROW or TK_STATEMENT */
00982   Token nameToken;        /* Token containing zName. Use during parsing only */
00983 
00984   TriggerStep *step_list; /* Link list of trigger program steps             */
00985   Trigger *pNext;         /* Next trigger associated with the table */
00986 };
00987 
00988 /*
00989  * An instance of struct TriggerStep is used to store a single SQL statement
00990  * that is a part of a trigger-program. 
00991  *
00992  * Instances of struct TriggerStep are stored in a singly linked list (linked
00993  * using the "pNext" member) referenced by the "step_list" member of the 
00994  * associated struct Trigger instance. The first element of the linked list is
00995  * the first step of the trigger-program.
00996  * 
00997  * The "op" member indicates whether this is a "DELETE", "INSERT", "UPDATE" or
00998  * "SELECT" statement. The meanings of the other members is determined by the 
00999  * value of "op" as follows:
01000  *
01001  * (op == TK_INSERT)
01002  * orconf    -> stores the ON CONFLICT algorithm
01003  * pSelect   -> If this is an INSERT INTO ... SELECT ... statement, then
01004  *              this stores a pointer to the SELECT statement. Otherwise NULL.
01005  * target    -> A token holding the name of the table to insert into.
01006  * pExprList -> If this is an INSERT INTO ... VALUES ... statement, then
01007  *              this stores values to be inserted. Otherwise NULL.
01008  * pIdList   -> If this is an INSERT INTO ... (<column-names>) VALUES ... 
01009  *              statement, then this stores the column-names to be
01010  *              inserted into.
01011  *
01012  * (op == TK_DELETE)
01013  * target    -> A token holding the name of the table to delete from.
01014  * pWhere    -> The WHERE clause of the DELETE statement if one is specified.
01015  *              Otherwise NULL.
01016  * 
01017  * (op == TK_UPDATE)
01018  * target    -> A token holding the name of the table to update rows of.
01019  * pWhere    -> The WHERE clause of the UPDATE statement if one is specified.
01020  *              Otherwise NULL.
01021  * pExprList -> A list of the columns to update and the expressions to update
01022  *              them to. See sqliteUpdate() documentation of "pChanges"
01023  *              argument.
01024  * 
01025  */
01026 struct TriggerStep {
01027   int op;              /* One of TK_DELETE, TK_UPDATE, TK_INSERT, TK_SELECT */
01028   int orconf;          /* OE_Rollback etc. */
01029   Trigger *pTrig;      /* The trigger that this step is a part of */
01030 
01031   Select *pSelect;     /* Valid for SELECT and sometimes 
01032               INSERT steps (when pExprList == 0) */
01033   Token target;        /* Valid for DELETE, UPDATE, INSERT steps */
01034   Expr *pWhere;        /* Valid for DELETE, UPDATE steps */
01035   ExprList *pExprList; /* Valid for UPDATE statements and sometimes 
01036                INSERT steps (when pSelect == 0)         */
01037   IdList *pIdList;     /* Valid for INSERT statements only */
01038 
01039   TriggerStep * pNext; /* Next in the link-list */
01040 };
01041 
01042 /*
01043  * An instance of struct TriggerStack stores information required during code
01044  * generation of a single trigger program. While the trigger program is being
01045  * coded, its associated TriggerStack instance is pointed to by the
01046  * "pTriggerStack" member of the Parse structure.
01047  *
01048  * The pTab member points to the table that triggers are being coded on. The 
01049  * newIdx member contains the index of the vdbe cursor that points at the temp
01050  * table that stores the new.* references. If new.* references are not valid
01051  * for the trigger being coded (for example an ON DELETE trigger), then newIdx
01052  * is set to -1. The oldIdx member is analogous to newIdx, for old.* references.
01053  *
01054  * The ON CONFLICT policy to be used for the trigger program steps is stored 
01055  * as the orconf member. If this is OE_Default, then the ON CONFLICT clause 
01056  * specified for individual triggers steps is used.
01057  *
01058  * struct TriggerStack has a "pNext" member, to allow linked lists to be
01059  * constructed. When coding nested triggers (triggers fired by other triggers)
01060  * each nested trigger stores its parent trigger's TriggerStack as the "pNext" 
01061  * pointer. Once the nested trigger has been coded, the pNext value is restored
01062  * to the pTriggerStack member of the Parse stucture and coding of the parent
01063  * trigger continues.
01064  *
01065  * Before a nested trigger is coded, the linked list pointed to by the 
01066  * pTriggerStack is scanned to ensure that the trigger is not about to be coded
01067  * recursively. If this condition is detected, the nested trigger is not coded.
01068  */
01069 struct TriggerStack {
01070   Table *pTab;         /* Table that triggers are currently being coded on */
01071   int newIdx;          /* Index of vdbe cursor to "new" temp table */
01072   int oldIdx;          /* Index of vdbe cursor to "old" temp table */
01073   int orconf;          /* Current orconf policy */
01074   int ignoreJump;      /* where to jump to for a RAISE(IGNORE) */
01075   Trigger *pTrigger;   /* The trigger currently being coded */
01076   TriggerStack *pNext; /* Next trigger down on the trigger stack */
01077 };
01078 
01079 /*
01080 ** The following structure contains information used by the sqliteFix...
01081 ** routines as they walk the parse tree to make database references
01082 ** explicit.  
01083 */
01084 typedef struct DbFixer DbFixer;
01085 struct DbFixer {
01086   Parse *pParse;      /* The parsing context.  Error messages written here */
01087   const char *zDb;    /* Make sure all objects are contained in this database */
01088   const char *zType;  /* Type of the container - used for error messages */
01089   const Token *pName; /* Name of the container - used for error messages */
01090 };
01091 
01092 /*
01093  * This global flag is set for performance testing of triggers. When it is set
01094  * SQLite will perform the overhead of building new and old trigger references 
01095  * even when no triggers exist
01096  */
01097 extern int always_code_trigger_setup;
01098 
01099 /*
01100 ** Internal function prototypes
01101 */
01102 int sqliteStrICmp(const char *, const char *);
01103 int sqliteStrNICmp(const char *, const char *, int);
01104 int sqliteHashNoCase(const char *, int);
01105 int sqliteIsNumber(const char*);
01106 int sqliteCompare(const char *, const char *);
01107 int sqliteSortCompare(const char *, const char *);
01108 void sqliteRealToSortable(double r, char *);
01109 #ifdef MEMORY_DEBUG
01110   void *sqliteMalloc_(int,int,char*,int);
01111   void sqliteFree_(void*,char*,int);
01112   void *sqliteRealloc_(void*,int,char*,int);
01113   char *sqliteStrDup_(const char*,char*,int);
01114   char *sqliteStrNDup_(const char*, int,char*,int);
01115   void sqliteCheckMemory(void*,int);
01116 #else
01117   void *sqliteMalloc(int);
01118   void *sqliteMallocRaw(int);
01119   void sqliteFree(void*);
01120   void *sqliteRealloc(void*,int);
01121   char *sqliteStrDup(const char*);
01122   char *sqliteStrNDup(const char*, int);
01123 # define sqliteCheckMemory(a,b)
01124 #endif
01125 char *sqliteMPrintf(const char*, ...);
01126 char *sqliteVMPrintf(const char*, va_list);
01127 void sqliteSetString(char **, ...);
01128 void sqliteSetNString(char **, ...);
01129 void sqliteErrorMsg(Parse*, const char*, ...);
01130 void sqliteDequote(char*);
01131 int sqliteKeywordCode(const char*, int);
01132 int sqliteRunParser(Parse*, const char*, char **);
01133 void sqliteExec(Parse*);
01134 Expr *sqliteExpr(int, Expr*, Expr*, Token*);
01135 void sqliteExprSpan(Expr*,Token*,Token*);
01136 Expr *sqliteExprFunction(ExprList*, Token*);
01137 void sqliteExprDelete(Expr*);
01138 ExprList *sqliteExprListAppend(ExprList*,Expr*,Token*);
01139 void sqliteExprListDelete(ExprList*);
01140 int sqliteInit(sqlite*, char**);
01141 void sqlitePragma(Parse*,Token*,Token*,int);
01142 void sqliteResetInternalSchema(sqlite*, int);
01143 void sqliteBeginParse(Parse*,int);
01144 void sqliteRollbackInternalChanges(sqlite*);
01145 void sqliteCommitInternalChanges(sqlite*);
01146 Table *sqliteResultSetOfSelect(Parse*,char*,Select*);
01147 void sqliteOpenMasterTable(Vdbe *v, int);
01148 void sqliteStartTable(Parse*,Token*,Token*,int,int);
01149 void sqliteAddColumn(Parse*,Token*);
01150 void sqliteAddNotNull(Parse*, int);
01151 void sqliteAddPrimaryKey(Parse*, IdList*, int);
01152 void sqliteAddColumnType(Parse*,Token*,Token*);
01153 void sqliteAddDefaultValue(Parse*,Token*,int);
01154 int sqliteCollateType(const char*, int);
01155 void sqliteAddCollateType(Parse*, int);
01156 void sqliteEndTable(Parse*,Token*,Select*);
01157 void sqliteCreateView(Parse*,Token*,Token*,Select*,int);
01158 int sqliteViewGetColumnNames(Parse*,Table*);
01159 void sqliteDropTable(Parse*, Token*, int);
01160 void sqliteDeleteTable(sqlite*, Table*);
01161 void sqliteInsert(Parse*, SrcList*, ExprList*, Select*, IdList*, int);
01162 IdList *sqliteIdListAppend(IdList*, Token*);
01163 int sqliteIdListIndex(IdList*,const char*);
01164 SrcList *sqliteSrcListAppend(SrcList*, Token*, Token*);
01165 void sqliteSrcListAddAlias(SrcList*, Token*);
01166 void sqliteSrcListAssignCursors(Parse*, SrcList*);
01167 void sqliteIdListDelete(IdList*);
01168 void sqliteSrcListDelete(SrcList*);
01169 void sqliteCreateIndex(Parse*,Token*,SrcList*,IdList*,int,Token*,Token*);
01170 void sqliteDropIndex(Parse*, SrcList*);
01171 void sqliteAddKeyType(Vdbe*, ExprList*);
01172 void sqliteAddIdxKeyType(Vdbe*, Index*);
01173 int sqliteSelect(Parse*, Select*, int, int, Select*, int, int*);
01174 Select *sqliteSelectNew(ExprList*,SrcList*,Expr*,ExprList*,Expr*,ExprList*,
01175                         int,int,int);
01176 void sqliteSelectDelete(Select*);
01177 void sqliteSelectUnbind(Select*);
01178 Table *sqliteSrcListLookup(Parse*, SrcList*);
01179 int sqliteIsReadOnly(Parse*, Table*, int);
01180 void sqliteDeleteFrom(Parse*, SrcList*, Expr*);
01181 void sqliteUpdate(Parse*, SrcList*, ExprList*, Expr*, int);
01182 WhereInfo *sqliteWhereBegin(Parse*, SrcList*, Expr*, int, ExprList**);
01183 void sqliteWhereEnd(WhereInfo*);
01184 void sqliteExprCode(Parse*, Expr*);
01185 int sqliteExprCodeExprList(Parse*, ExprList*, int);
01186 void sqliteExprIfTrue(Parse*, Expr*, int, int);
01187 void sqliteExprIfFalse(Parse*, Expr*, int, int);
01188 Table *sqliteFindTable(sqlite*,const char*, const char*);
01189 Table *sqliteLocateTable(Parse*,const char*, const char*);
01190 Index *sqliteFindIndex(sqlite*,const char*, const char*);
01191 void sqliteUnlinkAndDeleteIndex(sqlite*,Index*);
01192 void sqliteCopy(Parse*, SrcList*, Token*, Token*, int);
01193 void sqliteVacuum(Parse*, Token*);
01194 int sqliteRunVacuum(char**, sqlite*);
01195 int sqliteGlobCompare(const unsigned char*,const unsigned char*);
01196 int sqliteLikeCompare(const unsigned char*,const unsigned char*);
01197 char *sqliteTableNameFromToken(Token*);
01198 int sqliteExprCheck(Parse*, Expr*, int, int*);
01199 int sqliteExprType(Expr*);
01200 int sqliteExprCompare(Expr*, Expr*);
01201 int sqliteFuncId(Token*);
01202 int sqliteExprResolveIds(Parse*, SrcList*, ExprList*, Expr*);
01203 int sqliteExprAnalyzeAggregates(Parse*, Expr*);
01204 Vdbe *sqliteGetVdbe(Parse*);
01205 void sqliteRandomness(int, void*);
01206 void sqliteRollbackAll(sqlite*);
01207 void sqliteCodeVerifySchema(Parse*, int);
01208 void sqliteBeginTransaction(Parse*, int);
01209 void sqliteCommitTransaction(Parse*);
01210 void sqliteRollbackTransaction(Parse*);
01211 int sqliteExprIsConstant(Expr*);
01212 int sqliteExprIsInteger(Expr*, int*);
01213 int sqliteIsRowid(const char*);
01214 void sqliteGenerateRowDelete(sqlite*, Vdbe*, Table*, int, int);
01215 void sqliteGenerateRowIndexDelete(sqlite*, Vdbe*, Table*, int, char*);
01216 void sqliteGenerateConstraintChecks(Parse*,Table*,int,char*,int,int,int,int);
01217 void sqliteCompleteInsertion(Parse*, Table*, int, char*, int, int, int);
01218 int sqliteOpenTableAndIndices(Parse*, Table*, int);
01219 void sqliteBeginWriteOperation(Parse*, int, int);
01220 void sqliteEndWriteOperation(Parse*);
01221 Expr *sqliteExprDup(Expr*);
01222 void sqliteTokenCopy(Token*, Token*);
01223 ExprList *sqliteExprListDup(ExprList*);
01224 SrcList *sqliteSrcListDup(SrcList*);
01225 IdList *sqliteIdListDup(IdList*);
01226 Select *sqliteSelectDup(Select*);
01227 FuncDef *sqliteFindFunction(sqlite*,const char*,int,int,int);
01228 void sqliteRegisterBuiltinFunctions(sqlite*);
01229 void sqliteRegisterDateTimeFunctions(sqlite*);
01230 int sqliteSafetyOn(sqlite*);
01231 int sqliteSafetyOff(sqlite*);
01232 int sqliteSafetyCheck(sqlite*);
01233 void sqliteChangeCookie(sqlite*, Vdbe*);
01234 void sqliteBeginTrigger(Parse*, Token*,int,int,IdList*,SrcList*,int,Expr*,int);
01235 void sqliteFinishTrigger(Parse*, TriggerStep*, Token*);
01236 void sqliteDropTrigger(Parse*, SrcList*);
01237 void sqliteDropTriggerPtr(Parse*, Trigger*, int);
01238 int sqliteTriggersExist(Parse* , Trigger* , int , int , int, ExprList*);
01239 int sqliteCodeRowTrigger(Parse*, int, ExprList*, int, Table *, int, int, 
01240                          int, int);
01241 void sqliteViewTriggers(Parse*, Table*, Expr*, int, ExprList*);
01242 void sqliteDeleteTriggerStep(TriggerStep*);
01243 TriggerStep *sqliteTriggerSelectStep(Select*);
01244 TriggerStep *sqliteTriggerInsertStep(Token*, IdList*, ExprList*, Select*, int);
01245 TriggerStep *sqliteTriggerUpdateStep(Token*, ExprList*, Expr*, int);
01246 TriggerStep *sqliteTriggerDeleteStep(Token*, Expr*);
01247 void sqliteDeleteTrigger(Trigger*);
01248 int sqliteJoinType(Parse*, Token*, Token*, Token*);
01249 void sqliteCreateForeignKey(Parse*, IdList*, Token*, IdList*, int);
01250 void sqliteDeferForeignKey(Parse*, int);
01251 #ifndef SQLITE_OMIT_AUTHORIZATION
01252   void sqliteAuthRead(Parse*,Expr*,SrcList*);
01253   int sqliteAuthCheck(Parse*,int, const char*, const char*, const char*);
01254   void sqliteAuthContextPush(Parse*, AuthContext*, const char*);
01255   void sqliteAuthContextPop(AuthContext*);
01256 #else
01257 # define sqliteAuthRead(a,b,c)
01258 # define sqliteAuthCheck(a,b,c,d,e)    SQLITE_OK
01259 # define sqliteAuthContextPush(a,b,c)
01260 # define sqliteAuthContextPop(a)  ((void)(a))
01261 #endif
01262 void sqliteAttach(Parse*, Token*, Token*, Token*);
01263 void sqliteDetach(Parse*, Token*);
01264 int sqliteBtreeFactory(const sqlite *db, const char *zFilename,
01265                        int mode, int nPg, Btree **ppBtree);
01266 int sqliteFixInit(DbFixer*, Parse*, int, const char*, const Token*);
01267 int sqliteFixSrcList(DbFixer*, SrcList*);
01268 int sqliteFixSelect(DbFixer*, Select*);
01269 int sqliteFixExpr(DbFixer*, Expr*);
01270 int sqliteFixExprList(DbFixer*, ExprList*);
01271 int sqliteFixTriggerStep(DbFixer*, TriggerStep*);
01272 double sqliteAtoF(const char *z, const char **);
01273 char *sqlite_snprintf(int,char*,const char*,...);
01274 int sqliteFitsIn32Bits(const char *);

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