sqlite3Strlen30(p->zName),p);
    if( pOld ){
      assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
      db->mallocFailed = 1;
      return;
    }
    pParse->pNewTable = 0;
    db->nTable++;
    db->flags |= SQLITE_InternChanges;

#ifndef SQLITE_OMIT_ALTERTABLE
    if( !p->pSelect ){
      const char *zName = (const char *)pParse->sNameToken.z;
      int nName;
      assert( !pSelect && pCons && pEnd );

                             sqlite3Strlen30(p->zName),p);
    if( pOld ){
      assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
      db->mallocFailed = 1;
      return;
    }
    pParse->pNewTable = 0;

    db->flags |= SQLITE_InternChanges;

#ifndef SQLITE_OMIT_ALTERTABLE
    if( !p->pSelect ){
      const char *zName = (const char *)pParse->sNameToken.z;
      int nName;
      assert( !pSelect && pCons && pEnd );

** structure.
*/
struct PgHdr {
  sqlite3_pcache_page *pPage;    /* Pcache object page handle */
  void *pData;                   /* Page data */
  void *pExtra;                  /* Extra content */
  PgHdr *pDirty;                 /* Transient list of dirty pages */
  Pgno pgno;                     /* Page number for this page */
  Pager *pPager;                 /* The pager this page is part of */

#ifdef SQLITE_CHECK_PAGES
  u32 pageHash;                  /* Hash of page content */
#endif
  u16 flags;                     /* PGHDR flags defined below */

  /**********************************************************************
  ** Elements above are public.  All that follows is private to pcache.c

** structure.
*/
struct PgHdr {
  sqlite3_pcache_page *pPage;    /* Pcache object page handle */
  void *pData;                   /* Page data */
  void *pExtra;                  /* Extra content */
  PgHdr *pDirty;                 /* Transient list of dirty pages */

  Pager *pPager;                 /* The pager this page is part of */
  Pgno pgno;                     /* Page number for this page */
#ifdef SQLITE_CHECK_PAGES
  u32 pageHash;                  /* Hash of page content */
#endif
  u16 flags;                     /* PGHDR flags defined below */

  /**********************************************************************
  ** Elements above are public.  All that follows is private to pcache.c

*/
struct FuncDefHash {
  FuncDef *a[23];       /* Hash table for functions */
};

/*
** Each database connection is an instance of the following structure.
**
** The sqlite.lastRowid records the last insert rowid generated by an
** insert statement.  Inserts on views do not affect its value.  Each
** trigger has its own context, so that lastRowid can be updated inside
** triggers as usual.  The previous value will be restored once the trigger
** exits.  Upon entering a before or instead of trigger, lastRowid is no
** longer (since after version 2.8.12) reset to -1.
**
** The sqlite.nChange does not count changes within triggers and keeps no
** context.  It is reset at start of sqlite3_exec.
** The sqlite.lsChange represents the number of changes made by the last
** insert, update, or delete statement.  It remains constant throughout the
** length of a statement and is then updated by OP_SetCounts.  It keeps a
** context stack just like lastRowid so that the count of changes
** within a trigger is not seen outside the trigger.  Changes to views do not
** affect the value of lsChange.
** The sqlite.csChange keeps track of the number of current changes (since
** the last statement) and is used to update sqlite_lsChange.
**
** The member variables sqlite.errCode, sqlite.zErrMsg and sqlite.zErrMsg16
** store the most recent error code and, if applicable, string. The
** internal function sqlite3Error() is used to set these variables
** consistently.
*/
struct sqlite3 {
  sqlite3_vfs *pVfs;            /* OS Interface */
  int nDb;                      /* Number of backends currently in use */



  Db *aDb;                      /* All backends */

  int flags;                    /* Miscellaneous flags. See below */

  unsigned int openFlags;       /* Flags passed to sqlite3_vfs.xOpen() */
  int errCode;                  /* Most recent error code (SQLITE_*) */
  int errMask;                  /* & result codes with this before returning */
  u8 autoCommit;                /* The auto-commit flag. */
  u8 temp_store;                /* 1: file 2: memory 0: default */
  u8 mallocFailed;              /* True if we have seen a malloc failure */
  u8 dfltLockMode;              /* Default locking-mode for attached dbs */
  signed char nextAutovac;      /* Autovac setting after VACUUM if >=0 */
  u8 suppressErr;               /* Do not issue error messages if true */
  u8 vtabOnConflict;            /* Value to return for s3_vtab_on_conflict() */

  int nextPagesize;             /* Pagesize after VACUUM if >0 */
  int nTable;                   /* Number of tables in the database */
  CollSeq *pDfltColl;           /* The default collating sequence (BINARY) */
  i64 lastRowid;                /* ROWID of most recent insert (see above) */
  u32 magic;                    /* Magic number for detect library misuse */
  int nChange;                  /* Value returned by sqlite3_changes() */
  int nTotalChange;             /* Value returned by sqlite3_total_changes() */
  sqlite3_mutex *mutex;         /* Connection mutex */
  int aLimit[SQLITE_N_LIMIT];   /* Limits */
  struct sqlite3InitInfo {      /* Information used during initialization */
    int iDb;                    /* When back is being initialized */
    int newTnum;                /* Rootpage of table being initialized */

    u8 busy;                    /* TRUE if currently initializing */
    u8 orphanTrigger;           /* Last statement is orphaned TEMP trigger */
  } init;
  int nExtension;               /* Number of loaded extensions */
  void **aExtension;            /* Array of shared library handles */
  struct Vdbe *pVdbe;           /* List of active virtual machines */
  int activeVdbeCnt;            /* Number of VDBEs currently executing */
  int writeVdbeCnt;             /* Number of active VDBEs that are writing */
  int vdbeExecCnt;              /* Number of nested calls to VdbeExec() */


  void (*xTrace)(void*,const char*);        /* Trace function */
  void *pTraceArg;                          /* Argument to the trace function */
  void (*xProfile)(void*,const char*,u64);  /* Profiling function */
  void *pProfileArg;                        /* Argument to profile function */
  void *pCommitArg;                 /* Argument to xCommitCallback() */   
  int (*xCommitCallback)(void*);    /* Invoked at every commit. */
  void *pRollbackArg;               /* Argument to xRollbackCallback() */   
................................................................................
#endif
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  int (*xProgress)(void *);     /* The progress callback */
  void *pProgressArg;           /* Argument to the progress callback */
  int nProgressOps;             /* Number of opcodes for progress callback */
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE

  Hash aModule;                 /* populated by sqlite3_create_module() */
  VtabCtx *pVtabCtx;            /* Context for active vtab connect/create */
  VTable **aVTrans;             /* Virtual tables with open transactions */
  int nVTrans;                  /* Allocated size of aVTrans */
  VTable *pDisconnect;    /* Disconnect these in next sqlite3_prepare() */
#endif
  FuncDefHash aFunc;            /* Hash table of connection functions */
  Hash aCollSeq;                /* All collating sequences */
  BusyHandler busyHandler;      /* Busy callback */
  int busyTimeout;              /* Busy handler timeout, in msec */
  Db aDbStatic[2];              /* Static space for the 2 default backends */
  Savepoint *pSavepoint;        /* List of active savepoints */

  int nSavepoint;               /* Number of non-transaction savepoints */
  int nStatement;               /* Number of nested statement-transactions  */
  u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
  i64 nDeferredCons;            /* Net deferred constraints this transaction. */
  int *pnBytesFreed;            /* If not NULL, increment this in DbFree() */

#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
  /* The following variables are all protected by the STATIC_MASTER 
  ** mutex, not by sqlite3.mutex. They are used by code in notify.c. 
  **
................................................................................
/*
** Possible values for FuncDef.flags
*/
#define SQLITE_FUNC_LIKE     0x01 /* Candidate for the LIKE optimization */
#define SQLITE_FUNC_CASE     0x02 /* Case-sensitive LIKE-type function */
#define SQLITE_FUNC_EPHEM    0x04 /* Ephemeral.  Delete with VDBE */
#define SQLITE_FUNC_NEEDCOLL 0x08 /* sqlite3GetFuncCollSeq() might be called */
#define SQLITE_FUNC_PRIVATE  0x10 /* Allowed for internal use only */
#define SQLITE_FUNC_COUNT    0x20 /* Built-in count(*) aggregate */
#define SQLITE_FUNC_COALESCE 0x40 /* Built-in coalesce() or ifnull() function */

/*
** The following three macros, FUNCTION(), LIKEFUNC() and AGGREGATE() are
** used to create the initializers for the FuncDef structures.
**
................................................................................
** Allowed values for Tabe.tabFlags.
*/
#define TF_Readonly        0x01    /* Read-only system table */
#define TF_Ephemeral       0x02    /* An ephemeral table */
#define TF_HasPrimaryKey   0x04    /* Table has a primary key */
#define TF_Autoincrement   0x08    /* Integer primary key is autoincrement */
#define TF_Virtual         0x10    /* Is a virtual table */
#define TF_NeedMetadata    0x20    /* aCol[].zType and aCol[].pColl missing */



/*
** Test to see whether or not a table is a virtual table.  This is
** done as a macro so that it will be optimized out when virtual
** table support is omitted from the build.
*/
................................................................................
** it means this is not a unique index.  Otherwise it is a unique index
** and the value of Index.onError indicate the which conflict resolution 
** algorithm to employ whenever an attempt is made to insert a non-unique
** element.
*/
struct Index {
  char *zName;     /* Name of this index */
  int nColumn;     /* Number of columns in the table used by this index */
  int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
  tRowcnt *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */
  Table *pTable;   /* The SQL table being indexed */
  int tnum;        /* Page containing root of this index in database file */
  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
  u8 bUnordered;   /* Use this index for == or IN queries only */
  char *zColAff;   /* String defining the affinity of each column */
  Index *pNext;    /* The next index associated with the same table */
  Schema *pSchema; /* Schema containing this index */
  u8 *aSortOrder;  /* Array of size Index.nColumn. True==DESC, False==ASC */
  char **azColl;   /* Array of collation sequence names for index */





#ifdef SQLITE_ENABLE_STAT3
  int nSample;             /* Number of elements in aSample[] */
  tRowcnt avgEq;           /* Average nEq value for key values not in aSample */
  IndexSample *aSample;    /* Samples of the left-most key */
#endif
};

................................................................................
struct AggInfo {
  u8 directMode;          /* Direct rendering mode means take data directly
                          ** from source tables rather than from accumulators */
  u8 useSortingIdx;       /* In direct mode, reference the sorting index rather
                          ** than the source table */
  int sortingIdx;         /* Cursor number of the sorting index */
  int sortingIdxPTab;     /* Cursor number of pseudo-table */
  ExprList *pGroupBy;     /* The group by clause */
  int nSortingColumn;     /* Number of columns in the sorting index */

  struct AggInfo_col {    /* For each column used in source tables */
    Table *pTab;             /* Source table */
    int iTable;              /* Cursor number of the source table */
    int iColumn;             /* Column number within the source table */
    int iSorterColumn;       /* Column number in the sorting index */
    int iMem;                /* Memory location that acts as accumulator */
    Expr *pExpr;             /* The original expression */
................................................................................
** sequences for the ORDER BY clause.
*/
struct Select {
  ExprList *pEList;      /* The fields of the result */
  u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
  char affinity;         /* MakeRecord with this affinity for SRT_Set */
  u16 selFlags;          /* Various SF_* values */



  SrcList *pSrc;         /* The FROM clause */
  Expr *pWhere;          /* The WHERE clause */
  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  Select *pPrior;        /* Prior select in a compound select statement */
  Select *pNext;         /* Next select to the left in a compound */
  Select *pRightmost;    /* Right-most select in a compound select statement */
  Expr *pLimit;          /* LIMIT expression. NULL means not used. */
  Expr *pOffset;         /* OFFSET expression. NULL means not used. */
  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
  int addrOpenEphm[3];   /* OP_OpenEphem opcodes related to this select */
  double nSelectRow;     /* Estimated number of result rows */
};

/*
** Allowed values for Select.selFlags.  The "SF" prefix stands for
** "Select Flag".
*/
#define SF_Distinct        0x01  /* Output should be DISTINCT */
................................................................................
** The TriggerPrg.aColmask[0] variable is set to a mask of old.* columns
** accessed (or set to 0 for triggers fired as a result of INSERT 
** statements). Similarly, the TriggerPrg.aColmask[1] variable is set to
** a mask of new.* columns used by the program.
*/
struct TriggerPrg {
  Trigger *pTrigger;      /* Trigger this program was coded from */
  int orconf;             /* Default ON CONFLICT policy */
  SubProgram *pProgram;   /* Program implementing pTrigger/orconf */

  u32 aColmask[2];        /* Masks of old.*, new.* columns accessed */
  TriggerPrg *pNext;      /* Next entry in Parse.pTriggerPrg list */
};

/*
** The yDbMask datatype for the bitmask of all attached databases.
*/
#if SQLITE_MAX_ATTACHED>30
  typedef sqlite3_uint64 yDbMask;
................................................................................
** feature is enabled (if sqlite3Tsd()->useSharedData is true). They are
** used to store the set of table-locks required by the statement being
** compiled. Function sqlite3TableLock() is used to add entries to the
** list.
*/
struct Parse {
  sqlite3 *db;         /* The main database structure */
  int rc;              /* Return code from execution */
  char *zErrMsg;       /* An error message */
  Vdbe *pVdbe;         /* An engine for executing database bytecode */

  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
  u8 checkSchema;      /* Causes schema cookie check after an error */
  u8 nested;           /* Number of nested calls to the parser/code generator */
  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 nTempInUse;       /* Number of aTempReg[] currently checked out */




  int aTempReg[8];     /* Holding area for temporary registers */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
  int nOnce;           /* Number of OP_Once instructions so far */
  int ckBase;          /* Base register of data during check constraints */
  int iCacheLevel;     /* ColCache valid when aColCache[].iLevel<=iCacheLevel */
  int iCacheCnt;       /* Counter used to generate aColCache[].lru values */
  u8 nColCache;        /* Number of entries in aColCache[] */
  u8 iColCache;        /* Next entry in aColCache[] to replace */
  struct yColCache {
    int iTable;           /* Table cursor number */
    int iColumn;          /* Table column number */
    u8 tempReg;           /* iReg is a temp register that needs to be freed */
    int iLevel;           /* Nesting level */
    int iReg;             /* Reg with value of this column. 0 means none. */
    int lru;              /* Least recently used entry has the smallest value */
  } aColCache[SQLITE_N_COLCACHE];  /* One for each column cache entry */
  yDbMask writeMask;   /* Start a write transaction on these databases */
  yDbMask cookieMask;  /* Bitmask of schema verified databases */
  u8 isMultiWrite;     /* True if statement may affect/insert multiple rows */
  u8 mayAbort;         /* True if statement may throw an ABORT exception */
  int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
  int cookieValue[SQLITE_MAX_ATTACHED+2];  /* Values of cookies to verify */



#ifndef SQLITE_OMIT_SHARED_CACHE
  int nTableLock;        /* Number of locks in aTableLock */
  TableLock *aTableLock; /* Required table locks for shared-cache mode */
#endif
  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
  int regRoot;         /* Register holding root page number for new objects */
  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */
  int nMaxArg;         /* Max args passed to user function by sub-program */

  /* Information used while coding trigger programs. */
  Parse *pToplevel;    /* Parse structure for main program (or NULL) */
  Table *pTriggerTab;  /* Table triggers are being coded for */

  u32 oldmask;         /* Mask of old.* columns referenced */
  u32 newmask;         /* Mask of new.* columns referenced */
  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
  u8 disableTriggers;  /* True to disable triggers */
  double nQueryLoop;   /* Estimated number of iterations of a query */

  /* Above is constant between recursions.  Below is reset before and after
  ** each recursion */

  int nVar;            /* Number of '?' variables seen in the SQL so far */
  int nzVar;           /* Number of available slots in azVar[] */
  char **azVar;        /* Pointers to names of parameters */
  Vdbe *pReprepare;    /* VM being reprepared (sqlite3Reprepare()) */
  int nAlias;          /* Number of aliased result set columns */
  int *aAlias;         /* Register used to hold aliased result */
  u8 explain;          /* True if the EXPLAIN flag is found on the query */
  Token sNameToken;    /* Token with unqualified schema object name */
  Token sLastToken;    /* The last token parsed */
  const char *zTail;   /* All SQL text past the last semicolon parsed */
  Table *pNewTable;    /* A table being constructed by CREATE TABLE */
  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
#ifndef SQLITE_OMIT_VIRTUALTABLE
  Token sArg;                /* Complete text of a module argument */
  u8 declareVtab;            /* True if inside sqlite3_declare_vtab() */
  int nVtabLock;             /* Number of virtual tables to lock */
  Table **apVtabLock;        /* Pointer to virtual tables needing locking */
#endif
  int nHeight;            /* Expression tree height of current sub-select */
  Table *pZombieTab;      /* List of Table objects to delete after code gen */
  TriggerPrg *pTriggerPrg;    /* Linked list of coded triggers */

#ifndef SQLITE_OMIT_EXPLAIN
  int iSelectId;
  int iNextSelectId;
#endif
};





#ifdef SQLITE_OMIT_VIRTUALTABLE
  #define IN_DECLARE_VTAB 0
#else
  #define IN_DECLARE_VTAB (pParse->declareVtab)
#endif

/*
................................................................................

/*
** A pointer to this structure is used to communicate information
** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
*/
typedef struct {
  sqlite3 *db;        /* The database being initialized */
  int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
  char **pzErrMsg;    /* Error message stored here */

  int rc;             /* Result code stored here */
} InitData;

/*
** Structure containing global configuration data for the SQLite library.
**
** This structure also contains some state information.

*/
struct FuncDefHash {
  FuncDef *a[23];       /* Hash table for functions */
};

/*
** Each database connection is an instance of the following structure.























*/
struct sqlite3 {
  sqlite3_vfs *pVfs;            /* OS Interface */

  struct Vdbe *pVdbe;           /* List of active virtual machines */
  CollSeq *pDfltColl;           /* The default collating sequence (BINARY) */
  sqlite3_mutex *mutex;         /* Connection mutex */
  Db *aDb;                      /* All backends */
  int nDb;                      /* Number of backends currently in use */
  int flags;                    /* Miscellaneous flags. See below */
  i64 lastRowid;                /* ROWID of most recent insert (see above) */
  unsigned int openFlags;       /* Flags passed to sqlite3_vfs.xOpen() */
  int errCode;                  /* Most recent error code (SQLITE_*) */
  int errMask;                  /* & result codes with this before returning */
  u8 autoCommit;                /* The auto-commit flag. */
  u8 temp_store;                /* 1: file 2: memory 0: default */
  u8 mallocFailed;              /* True if we have seen a malloc failure */
  u8 dfltLockMode;              /* Default locking-mode for attached dbs */
  signed char nextAutovac;      /* Autovac setting after VACUUM if >=0 */
  u8 suppressErr;               /* Do not issue error messages if true */
  u8 vtabOnConflict;            /* Value to return for s3_vtab_on_conflict() */
  u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
  int nextPagesize;             /* Pagesize after VACUUM if >0 */



  u32 magic;                    /* Magic number for detect library misuse */
  int nChange;                  /* Value returned by sqlite3_changes() */
  int nTotalChange;             /* Value returned by sqlite3_total_changes() */

  int aLimit[SQLITE_N_LIMIT];   /* Limits */
  struct sqlite3InitInfo {      /* Information used during initialization */

    int newTnum;                /* Rootpage of table being initialized */
    u8 iDb;                     /* Which db file is being initialized */
    u8 busy;                    /* TRUE if currently initializing */
    u8 orphanTrigger;           /* Last statement is orphaned TEMP trigger */
  } init;



  int activeVdbeCnt;            /* Number of VDBEs currently executing */
  int writeVdbeCnt;             /* Number of active VDBEs that are writing */
  int vdbeExecCnt;              /* Number of nested calls to VdbeExec() */
  int nExtension;               /* Number of loaded extensions */
  void **aExtension;            /* Array of shared library handles */
  void (*xTrace)(void*,const char*);        /* Trace function */
  void *pTraceArg;                          /* Argument to the trace function */
  void (*xProfile)(void*,const char*,u64);  /* Profiling function */
  void *pProfileArg;                        /* Argument to profile function */
  void *pCommitArg;                 /* Argument to xCommitCallback() */   
  int (*xCommitCallback)(void*);    /* Invoked at every commit. */
  void *pRollbackArg;               /* Argument to xRollbackCallback() */   
................................................................................
#endif
#ifndef SQLITE_OMIT_PROGRESS_CALLBACK
  int (*xProgress)(void *);     /* The progress callback */
  void *pProgressArg;           /* Argument to the progress callback */
  int nProgressOps;             /* Number of opcodes for progress callback */
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
  int nVTrans;                  /* Allocated size of aVTrans */
  Hash aModule;                 /* populated by sqlite3_create_module() */
  VtabCtx *pVtabCtx;            /* Context for active vtab connect/create */
  VTable **aVTrans;             /* Virtual tables with open transactions */

  VTable *pDisconnect;    /* Disconnect these in next sqlite3_prepare() */
#endif
  FuncDefHash aFunc;            /* Hash table of connection functions */
  Hash aCollSeq;                /* All collating sequences */
  BusyHandler busyHandler;      /* Busy callback */

  Db aDbStatic[2];              /* Static space for the 2 default backends */
  Savepoint *pSavepoint;        /* List of active savepoints */
  int busyTimeout;              /* Busy handler timeout, in msec */
  int nSavepoint;               /* Number of non-transaction savepoints */
  int nStatement;               /* Number of nested statement-transactions  */

  i64 nDeferredCons;            /* Net deferred constraints this transaction. */
  int *pnBytesFreed;            /* If not NULL, increment this in DbFree() */

#ifdef SQLITE_ENABLE_UNLOCK_NOTIFY
  /* The following variables are all protected by the STATIC_MASTER 
  ** mutex, not by sqlite3.mutex. They are used by code in notify.c. 
  **
................................................................................
/*
** Possible values for FuncDef.flags
*/
#define SQLITE_FUNC_LIKE     0x01 /* Candidate for the LIKE optimization */
#define SQLITE_FUNC_CASE     0x02 /* Case-sensitive LIKE-type function */
#define SQLITE_FUNC_EPHEM    0x04 /* Ephemeral.  Delete with VDBE */
#define SQLITE_FUNC_NEEDCOLL 0x08 /* sqlite3GetFuncCollSeq() might be called */

#define SQLITE_FUNC_COUNT    0x20 /* Built-in count(*) aggregate */
#define SQLITE_FUNC_COALESCE 0x40 /* Built-in coalesce() or ifnull() function */

/*
** The following three macros, FUNCTION(), LIKEFUNC() and AGGREGATE() are
** used to create the initializers for the FuncDef structures.
**
................................................................................
** Allowed values for Tabe.tabFlags.
*/
#define TF_Readonly        0x01    /* Read-only system table */
#define TF_Ephemeral       0x02    /* An ephemeral table */
#define TF_HasPrimaryKey   0x04    /* Table has a primary key */
#define TF_Autoincrement   0x08    /* Integer primary key is autoincrement */
#define TF_Virtual         0x10    /* Is a virtual table */




/*
** Test to see whether or not a table is a virtual table.  This is
** done as a macro so that it will be optimized out when virtual
** table support is omitted from the build.
*/
................................................................................
** it means this is not a unique index.  Otherwise it is a unique index
** and the value of Index.onError indicate the which conflict resolution 
** algorithm to employ whenever an attempt is made to insert a non-unique
** element.
*/
struct Index {
  char *zName;     /* Name of this index */

  int *aiColumn;   /* Which columns are used by this index.  1st is 0 */
  tRowcnt *aiRowEst; /* Result of ANALYZE: Est. rows selected by each column */
  Table *pTable;   /* The SQL table being indexed */




  char *zColAff;   /* String defining the affinity of each column */
  Index *pNext;    /* The next index associated with the same table */
  Schema *pSchema; /* Schema containing this index */
  u8 *aSortOrder;  /* Array of size Index.nColumn. True==DESC, False==ASC */
  char **azColl;   /* Array of collation sequence names for index */
  int nColumn;     /* Number of columns in the table used by this index */
  int tnum;        /* Page containing root of this index in database file */
  u8 onError;      /* OE_Abort, OE_Ignore, OE_Replace, or OE_None */
  u8 autoIndex;    /* True if is automatically created (ex: by UNIQUE) */
  u8 bUnordered;   /* Use this index for == or IN queries only */
#ifdef SQLITE_ENABLE_STAT3
  int nSample;             /* Number of elements in aSample[] */
  tRowcnt avgEq;           /* Average nEq value for key values not in aSample */
  IndexSample *aSample;    /* Samples of the left-most key */
#endif
};

................................................................................
struct AggInfo {
  u8 directMode;          /* Direct rendering mode means take data directly
                          ** from source tables rather than from accumulators */
  u8 useSortingIdx;       /* In direct mode, reference the sorting index rather
                          ** than the source table */
  int sortingIdx;         /* Cursor number of the sorting index */
  int sortingIdxPTab;     /* Cursor number of pseudo-table */

  int nSortingColumn;     /* Number of columns in the sorting index */
  ExprList *pGroupBy;     /* The group by clause */
  struct AggInfo_col {    /* For each column used in source tables */
    Table *pTab;             /* Source table */
    int iTable;              /* Cursor number of the source table */
    int iColumn;             /* Column number within the source table */
    int iSorterColumn;       /* Column number in the sorting index */
    int iMem;                /* Memory location that acts as accumulator */
    Expr *pExpr;             /* The original expression */
................................................................................
** sequences for the ORDER BY clause.
*/
struct Select {
  ExprList *pEList;      /* The fields of the result */
  u8 op;                 /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
  char affinity;         /* MakeRecord with this affinity for SRT_Set */
  u16 selFlags;          /* Various SF_* values */
  int iLimit, iOffset;   /* Memory registers holding LIMIT & OFFSET counters */
  int addrOpenEphm[3];   /* OP_OpenEphem opcodes related to this select */
  double nSelectRow;     /* Estimated number of result rows */
  SrcList *pSrc;         /* The FROM clause */
  Expr *pWhere;          /* The WHERE clause */
  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  Select *pPrior;        /* Prior select in a compound select statement */
  Select *pNext;         /* Next select to the left in a compound */
  Select *pRightmost;    /* Right-most select in a compound select statement */
  Expr *pLimit;          /* LIMIT expression. NULL means not used. */
  Expr *pOffset;         /* OFFSET expression. NULL means not used. */



};

/*
** Allowed values for Select.selFlags.  The "SF" prefix stands for
** "Select Flag".
*/
#define SF_Distinct        0x01  /* Output should be DISTINCT */
................................................................................
** The TriggerPrg.aColmask[0] variable is set to a mask of old.* columns
** accessed (or set to 0 for triggers fired as a result of INSERT 
** statements). Similarly, the TriggerPrg.aColmask[1] variable is set to
** a mask of new.* columns used by the program.
*/
struct TriggerPrg {
  Trigger *pTrigger;      /* Trigger this program was coded from */
  TriggerPrg *pNext;      /* Next entry in Parse.pTriggerPrg list */
  SubProgram *pProgram;   /* Program implementing pTrigger/orconf */
  int orconf;             /* Default ON CONFLICT policy */
  u32 aColmask[2];        /* Masks of old.*, new.* columns accessed */

};

/*
** The yDbMask datatype for the bitmask of all attached databases.
*/
#if SQLITE_MAX_ATTACHED>30
  typedef sqlite3_uint64 yDbMask;
................................................................................
** feature is enabled (if sqlite3Tsd()->useSharedData is true). They are
** used to store the set of table-locks required by the statement being
** compiled. Function sqlite3TableLock() is used to add entries to the
** list.
*/
struct Parse {
  sqlite3 *db;         /* The main database structure */

  char *zErrMsg;       /* An error message */
  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  int rc;              /* Return code from execution */
  u8 colNamesSet;      /* TRUE after OP_ColumnName has been issued to pVdbe */
  u8 checkSchema;      /* Causes schema cookie check after an error */
  u8 nested;           /* Number of nested calls to the parser/code generator */
  u8 nTempReg;         /* Number of temporary registers in aTempReg[] */
  u8 nTempInUse;       /* Number of aTempReg[] currently checked out */
  u8 nColCache;        /* Number of entries in aColCache[] */
  u8 iColCache;        /* Next entry in aColCache[] to replace */
  u8 isMultiWrite;     /* True if statement may modify/insert multiple rows */
  u8 mayAbort;         /* True if statement may throw an ABORT exception */
  int aTempReg[8];     /* Holding area for temporary registers */
  int nRangeReg;       /* Size of the temporary register block */
  int iRangeReg;       /* First register in temporary register block */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
  int nOnce;           /* Number of OP_Once instructions so far */
  int ckBase;          /* Base register of data during check constraints */
  int iCacheLevel;     /* ColCache valid when aColCache[].iLevel<=iCacheLevel */
  int iCacheCnt;       /* Counter used to generate aColCache[].lru values */


  struct yColCache {
    int iTable;           /* Table cursor number */
    int iColumn;          /* Table column number */
    u8 tempReg;           /* iReg is a temp register that needs to be freed */
    int iLevel;           /* Nesting level */
    int iReg;             /* Reg with value of this column. 0 means none. */
    int lru;              /* Least recently used entry has the smallest value */
  } aColCache[SQLITE_N_COLCACHE];  /* One for each column cache entry */
  yDbMask writeMask;   /* Start a write transaction on these databases */
  yDbMask cookieMask;  /* Bitmask of schema verified databases */


  int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
  int cookieValue[SQLITE_MAX_ATTACHED+2];  /* Values of cookies to verify */
  int regRowid;        /* Register holding rowid of CREATE TABLE entry */
  int regRoot;         /* Register holding root page number for new objects */
  int nMaxArg;         /* Max args passed to user function by sub-program */
#ifndef SQLITE_OMIT_SHARED_CACHE
  int nTableLock;        /* Number of locks in aTableLock */
  TableLock *aTableLock; /* Required table locks for shared-cache mode */
#endif


  AutoincInfo *pAinc;  /* Information about AUTOINCREMENT counters */


  /* Information used while coding trigger programs. */
  Parse *pToplevel;    /* Parse structure for main program (or NULL) */
  Table *pTriggerTab;  /* Table triggers are being coded for */
  double nQueryLoop;   /* Estimated number of iterations of a query */
  u32 oldmask;         /* Mask of old.* columns referenced */
  u32 newmask;         /* Mask of new.* columns referenced */
  u8 eTriggerOp;       /* TK_UPDATE, TK_INSERT or TK_DELETE */
  u8 eOrconf;          /* Default ON CONFLICT policy for trigger steps */
  u8 disableTriggers;  /* True to disable triggers */


  /* Above is constant between recursions.  Below is reset before and after
  ** each recursion */

  int nVar;                 /* Number of '?' variables seen in the SQL so far */
  int nzVar;                /* Number of available slots in azVar[] */
  u8 explain;               /* True if the EXPLAIN flag is found on the query */
#ifndef SQLITE_OMIT_VIRTUALTABLE
  u8 declareVtab;           /* True if inside sqlite3_declare_vtab() */
  int nVtabLock;            /* Number of virtual tables to lock */
#endif
  int nAlias;               /* Number of aliased result set columns */
  int nHeight;              /* Expression tree height of current sub-select */
#ifndef SQLITE_OMIT_EXPLAIN
  int iSelectId;            /* ID of current select for EXPLAIN output */
  int iNextSelectId;        /* Next available select ID for EXPLAIN output */
#endif
  char **azVar;             /* Pointers to names of parameters */
  Vdbe *pReprepare;         /* VM being reprepared (sqlite3Reprepare()) */
  int *aAlias;              /* Register used to hold aliased result */
  const char *zTail;        /* All SQL text past the last semicolon parsed */
  Table *pNewTable;         /* A table being constructed by CREATE TABLE */
  Trigger *pNewTrigger;     /* Trigger under construct by a CREATE TRIGGER */
  const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
  Token sNameToken;         /* Token with unqualified schema object name */
  Token sLastToken;         /* The last token parsed */
#ifndef SQLITE_OMIT_VIRTUALTABLE
  Token sArg;               /* Complete text of a module argument */
  Table **apVtabLock;       /* Pointer to virtual tables needing locking */
#endif
  Table *pZombieTab;        /* List of Table objects to delete after code gen */
  TriggerPrg *pTriggerPrg;  /* Linked list of coded triggers */
};

/*
** Return true if currently inside an sqlite3_declare_vtab() call.
*/
#ifdef SQLITE_OMIT_VIRTUALTABLE
  #define IN_DECLARE_VTAB 0
#else
  #define IN_DECLARE_VTAB (pParse->declareVtab)
#endif

/*
................................................................................

/*
** A pointer to this structure is used to communicate information
** from sqlite3Init and OP_ParseSchema into the sqlite3InitCallback.
*/
typedef struct {
  sqlite3 *db;        /* The database being initialized */

  char **pzErrMsg;    /* Error message stored here */
  int iDb;            /* 0 for main database.  1 for TEMP, 2.. for ATTACHed */
  int rc;             /* Result code stored here */
} InitData;

/*
** Structure containing global configuration data for the SQLite library.
**
** This structure also contains some state information.

** on the file.
**
** If a write-transaction is started and the Vdbe.usesStmtJournal flag is
** true (this flag is set if the Vdbe may modify more than one row and may
** throw an ABORT exception), a statement transaction may also be opened.
** More specifically, a statement transaction is opened iff the database
** connection is currently not in autocommit mode, or if there are other
** active statements. A statement transaction allows the affects of this
** VDBE to be rolled back after an error without having to roll back the
** entire transaction. If no error is encountered, the statement transaction
** will automatically commit when the VDBE halts.
**
** If P2 is zero, then a read-lock is obtained on the database file.
*/
case OP_Transaction: {

** on the file.
**
** If a write-transaction is started and the Vdbe.usesStmtJournal flag is
** true (this flag is set if the Vdbe may modify more than one row and may
** throw an ABORT exception), a statement transaction may also be opened.
** More specifically, a statement transaction is opened iff the database
** connection is currently not in autocommit mode, or if there are other
** active statements. A statement transaction allows the changes made by this
** VDBE to be rolled back after an error without having to roll back the
** entire transaction. If no error is encountered, the statement transaction
** will automatically commit when the VDBE halts.
**
** If P2 is zero, then a read-lock is obtained on the database file.
*/
case OP_Transaction: {