Esempio n. 1
0
/*
** Rerun the compilation of a statement after a schema change.
**
** If the statement is successfully recompiled, return SQLITE_OK. Otherwise,
** if the statement cannot be recompiled because another connection has
** locked the sqlite3_master table, return SQLITE_LOCKED. If any other error
** occurs, return SQLITE_SCHEMA.
*/
int sqlite3Reprepare(Vdbe *p){
  int rc;
  sqlite3_stmt *pNew;
  const char *zSql;
  sqlite3 *db;

  assert( sqlite3_mutex_held(sqlite3VdbeDb(p)->mutex) );
  zSql = sqlite3_sql((sqlite3_stmt *)p);
  assert( zSql!=0 );  /* Reprepare only called for prepare_v2() statements */
  db = sqlite3VdbeDb(p);
  assert( sqlite3_mutex_held(db->mutex) );
  rc = sqlite3LockAndPrepare(db, zSql, -1, 0, &pNew, 0);
  if( rc ){
    if( rc==SQLITE_NOMEM ){
      db->mallocFailed = 1;
    }
    assert( pNew==0 );
    return (rc==SQLITE_LOCKED) ? SQLITE_LOCKED : SQLITE_SCHEMA;
  }else{
    assert( pNew!=0 );
  }
  sqlite3VdbeSwap((Vdbe*)pNew, p);
  sqlite3TransferBindings(pNew, (sqlite3_stmt*)p);
  sqlite3VdbeResetStepResult((Vdbe*)pNew);
  sqlite3VdbeFinalize((Vdbe*)pNew);
  return SQLITE_OK;
}
Esempio n. 2
0
/*
** The most recently coded instruction was an OP_Column to retrieve the
** i-th column of table pTab. This routine sets the P4 parameter of the 
** OP_Column to the default value, if any.
**
** The default value of a column is specified by a DEFAULT clause in the 
** column definition. This was either supplied by the user when the table
** was created, or added later to the table definition by an ALTER TABLE
** command. If the latter, then the row-records in the table btree on disk
** may not contain a value for the column and the default value, taken
** from the P4 parameter of the OP_Column instruction, is returned instead.
** If the former, then all row-records are guaranteed to include a value
** for the column and the P4 value is not required.
**
** Column definitions created by an ALTER TABLE command may only have 
** literal default values specified: a number, null or a string. (If a more
** complicated default expression value was provided, it is evaluated 
** when the ALTER TABLE is executed and one of the literal values written
** into the sqlite_master table.)
**
** Therefore, the P4 parameter is only required if the default value for
** the column is a literal number, string or null. The sqlite3ValueFromExpr()
** function is capable of transforming these types of expressions into
** sqlite3_value objects.
*/
void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
  if( pTab && !pTab->pSelect ){
    sqlite3_value *pValue;
    u8 enc = ENC(sqlite3VdbeDb(v));
    Column *pCol = &pTab->aCol[i];
    VdbeComment((v, "%s.%s", pTab->zName, pCol->zName));
    assert( i<pTab->nCol );
    sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc, 
                         pCol->affinity, &pValue);
    if( pValue ){
      sqlite3VdbeChangeP4(v, -1, (const char *)pValue, P4_MEM);
    }
  }
}
Esempio n. 3
0
/*
** The most recently coded instruction was an OP_Column to retrieve column
** 'i' of table pTab. This routine sets the P3 parameter of the 
** OP_Column to the default value, if any.
**
** The default value of a column is specified by a DEFAULT clause in the 
** column definition. This was either supplied by the user when the table
** was created, or added later to the table definition by an ALTER TABLE
** command. If the latter, then the row-records in the table btree on disk
** may not contain a value for the column and the default value, taken
** from the P3 parameter of the OP_Column instruction, is returned instead.
** If the former, then all row-records are guaranteed to include a value
** for the column and the P3 value is not required.
**
** Column definitions created by an ALTER TABLE command may only have 
** literal default values specified: a number, null or a string. (If a more
** complicated default expression value was provided, it is evaluated 
** when the ALTER TABLE is executed and one of the literal values written
** into the sqlite_master table.)
**
** Therefore, the P3 parameter is only required if the default value for
** the column is a literal number, string or null. The sqlite3ValueFromExpr()
** function is capable of transforming these types of expressions into
** sqlite3_value objects.
*/
void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i){
  if( pTab && !pTab->pSelect ){
    sqlite3_value *pValue;
    u8 enc = sqlite3VdbeDb(v)->enc;
    Column *pCol = &pTab->aCol[i];
    sqlite3ValueFromExpr(pCol->pDflt, enc, pCol->affinity, &pValue);
    sqlite3VdbeChangeP3(v, -1, (const char *)pValue, P3_MEM);
  }
}
Esempio n. 4
0
/*
** The most recently coded instruction was an OP_Column to retrieve the
** i-th column of table pTab. This routine sets the P4 parameter of the 
** OP_Column to the default value, if any.
**
** The default value of a column is specified by a DEFAULT clause in the 
** column definition. This was either supplied by the user when the table
** was created, or added later to the table definition by an ALTER TABLE
** command. If the latter, then the row-records in the table btree on disk
** may not contain a value for the column and the default value, taken
** from the P4 parameter of the OP_Column instruction, is returned instead.
** If the former, then all row-records are guaranteed to include a value
** for the column and the P4 value is not required.
**
** Column definitions created by an ALTER TABLE command may only have 
** literal default values specified: a number, null or a string. (If a more
** complicated default expression value was provided, it is evaluated 
** when the ALTER TABLE is executed and one of the literal values written
** into the sqlite_master table.)
**
** Therefore, the P4 parameter is only required if the default value for
** the column is a literal number, string or null. The sqlite3ValueFromExpr()
** function is capable of transforming these types of expressions into
** sqlite3_value objects.
**
** If parameter iReg is not negative, code an OP_RealAffinity instruction
** on register iReg. This is used when an equivalent integer value is 
** stored in place of an 8-byte floating point value in order to save 
** space.
*/
void sqlite3ColumnDefault(Vdbe *v, Table *pTab, int i, int iReg){
  assert( pTab!=0 );
  if( !pTab->pSelect ){
    sqlite3_value *pValue = 0;
    u8 enc = ENC(sqlite3VdbeDb(v));
    Column *pCol = &pTab->aCol[i];
    VdbeComment((v, "%s.%s", pTab->zName, pCol->zName));
    assert( i<pTab->nCol );
    sqlite3ValueFromExpr(sqlite3VdbeDb(v), pCol->pDflt, enc, 
                         pCol->affinity, &pValue);
    if( pValue ){
      sqlite3VdbeChangeP4(v, -1, (const char *)pValue, P4_MEM);
    }
#ifndef SQLITE_OMIT_FLOATING_POINT
    if( pTab->aCol[i].affinity==SQLITE_AFF_REAL ){
      sqlite3VdbeAddOp1(v, OP_RealAffinity, iReg);
    }
#endif
  }
}
Esempio n. 5
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/*
** This routine generates code that opens the sqlite_stat1 table on cursor
** iStatCur.
**
** If the sqlite_stat1 tables does not previously exist, it is created.
** If it does previously exist, all entires associated with table zWhere
** are removed.  If zWhere==0 then all entries are removed.
*/
static void openStatTable(
  Parse *pParse,          /* Parsing context */
  int iDb,                /* The database we are looking in */
  int iStatCur,           /* Open the sqlite_stat1 table on this cursor */
  const char *zWhere      /* Delete entries associated with this table */
){
  sqlite3 *db = pParse->db;
  Db *pDb;
  int iRootPage;
  Table *pStat;
  Vdbe *v = sqlite3GetVdbe(pParse);

  if( v==0 ) return;
  assert( sqlite3BtreeHoldsAllMutexes(db) );
  assert( sqlite3VdbeDb(v)==db );
  pDb = &db->aDb[iDb];
  if( (pStat = sqlite3FindTable(db, "sqlite_stat1", pDb->zName))==0 ){
    /* The sqlite_stat1 tables does not exist.  Create it.  
    ** Note that a side-effect of the CREATE TABLE statement is to leave
    ** the rootpage of the new table on the top of the stack.  This is
    ** important because the OpenWrite opcode below will be needing it. */
    sqlite3NestedParse(pParse,
      "CREATE TABLE %Q.sqlite_stat1(tbl,idx,stat)",
      pDb->zName
    );
    iRootPage = 0;  /* Cause rootpage to be taken from top of stack */
  }else if( zWhere ){
    /* The sqlite_stat1 table exists.  Delete all entries associated with
    ** the table zWhere. */
    sqlite3NestedParse(pParse,
       "DELETE FROM %Q.sqlite_stat1 WHERE tbl=%Q",
       pDb->zName, zWhere
    );
    iRootPage = pStat->tnum;
  }else{
    /* The sqlite_stat1 table already exists.  Delete all rows. */
    iRootPage = pStat->tnum;
    sqlite3VdbeAddOp(v, OP_Clear, pStat->tnum, iDb);
  }

  /* Open the sqlite_stat1 table for writing. Unless it was created
  ** by this vdbe program, lock it for writing at the shared-cache level. 
  ** If this vdbe did create the sqlite_stat1 table, then it must have 
  ** already obtained a schema-lock, making the write-lock redundant.
  */
  if( iRootPage>0 ){
    sqlite3TableLock(pParse, iDb, iRootPage, 1, "sqlite_stat1");
  }
  sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
  sqlite3VdbeAddOp(v, OP_OpenWrite, iStatCur, iRootPage);
  sqlite3VdbeAddOp(v, OP_SetNumColumns, iStatCur, 3);
}
Esempio n. 6
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/*
** Rerun the compilation of a statement after a schema change.
** Return true if the statement was recompiled successfully.
** Return false if there is an error of some kind.
*/
int sqlite3Reprepare(Vdbe *p){
  int rc;
  Vdbe *pNew;
  const char *zSql;
  sqlite3 *db;
  
  zSql = sqlite3VdbeGetSql(p);
  if( zSql==0 ){
    return 0;
  }
  db = sqlite3VdbeDb(p);
  rc = sqlite3Prepare(db, zSql, -1, 0, (sqlite3_stmt**)&pNew, 0);
  if( rc ){
    assert( pNew==0 );
    return 0;
  }else{
    assert( pNew!=0 );
  }
  sqlite3VdbeSwap(pNew, p);
  sqlite3_transfer_bindings((sqlite3_stmt*)pNew, (sqlite3_stmt*)p);
  sqlite3VdbeResetStepResult(pNew);
  sqlite3VdbeFinalize(pNew);
  return 1;
}
Esempio n. 7
0
/*
** Run the parser on the given SQL string.  The parser structure is
** passed in.  An SQLITE_ status code is returned.  If an error occurs
** then an and attempt is made to write an error message into 
** memory obtained from sqlite3_malloc() and to make *pzErrMsg point to that
** error message.
*/
int sqlite3RunParser(Parse *pParse, const char *zSql, char **pzErrMsg){
  int nErr = 0;                   /* Number of errors encountered */
  void *pEngine;                  /* The LEMON-generated LALR(1) parser */
  int n = 0;                      /* Length of the next token token */
  int tokenType;                  /* type of the next token */
  int lastTokenParsed = -1;       /* type of the previous token */
  sqlite3 *db = pParse->db;       /* The database connection */
  int mxSqlLen;                   /* Max length of an SQL string */
#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
  yyParser sEngine;    /* Space to hold the Lemon-generated Parser object */
#endif

  assert( zSql!=0 );
  mxSqlLen = db->aLimit[SQLITE_LIMIT_SQL_LENGTH];
  if( db->nVdbeActive==0 ){
    db->u1.isInterrupted = 0;
  }
  pParse->rc = SQLITE_OK;
  pParse->zTail = zSql;
  assert( pzErrMsg!=0 );
#ifdef SQLITE_DEBUG
  if( db->flags & SQLITE_ParserTrace ){
    printf("parser: [[[%s]]]\n", zSql);
    sqlite3ParserTrace(stdout, "parser: ");
  }else{
    sqlite3ParserTrace(0, 0);
  }
#endif
#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
  pEngine = &sEngine;
  sqlite3ParserInit(pEngine, pParse);
#else
  pEngine = sqlite3ParserAlloc(sqlite3Malloc, pParse);
  if( pEngine==0 ){
    sqlite3OomFault(db);
    return SQLITE_NOMEM_BKPT;
  }
#endif
  assert( pParse->pNewTable==0 );
  assert( pParse->pNewTrigger==0 );
  assert( pParse->nVar==0 );
  assert( pParse->pVList==0 );
  while( 1 ){
    n = sqlite3GetToken((u8*)zSql, &tokenType);
    mxSqlLen -= n;
    if( mxSqlLen<0 ){
      pParse->rc = SQLITE_TOOBIG;
      break;
    }
#ifndef SQLITE_OMIT_WINDOWFUNC
    if( tokenType>=TK_WINDOW ){
      assert( tokenType==TK_SPACE || tokenType==TK_OVER || tokenType==TK_FILTER
           || tokenType==TK_ILLEGAL || tokenType==TK_WINDOW 
      );
#else
    if( tokenType>=TK_SPACE ){
      assert( tokenType==TK_SPACE || tokenType==TK_ILLEGAL );
#endif /* SQLITE_OMIT_WINDOWFUNC */
      if( db->u1.isInterrupted ){
        pParse->rc = SQLITE_INTERRUPT;
        break;
      }
      if( tokenType==TK_SPACE ){
        zSql += n;
        continue;
      }
      if( zSql[0]==0 ){
        /* Upon reaching the end of input, call the parser two more times
        ** with tokens TK_SEMI and 0, in that order. */
        if( lastTokenParsed==TK_SEMI ){
          tokenType = 0;
        }else if( lastTokenParsed==0 ){
          break;
        }else{
          tokenType = TK_SEMI;
        }
        n = 0;
#ifndef SQLITE_OMIT_WINDOWFUNC
      }else if( tokenType==TK_WINDOW ){
        assert( n==6 );
        tokenType = analyzeWindowKeyword((const u8*)&zSql[6]);
      }else if( tokenType==TK_OVER ){
        assert( n==4 );
        tokenType = analyzeOverKeyword((const u8*)&zSql[4], lastTokenParsed);
      }else if( tokenType==TK_FILTER ){
        assert( n==6 );
        tokenType = analyzeFilterKeyword((const u8*)&zSql[6], lastTokenParsed);
#endif /* SQLITE_OMIT_WINDOWFUNC */
      }else{
        sqlite3ErrorMsg(pParse, "unrecognized token: \"%.*s\"", n, zSql);
        break;
      }
    }
    pParse->sLastToken.z = zSql;
    pParse->sLastToken.n = n;
    sqlite3Parser(pEngine, tokenType, pParse->sLastToken);
    lastTokenParsed = tokenType;
    zSql += n;
    if( pParse->rc!=SQLITE_OK || db->mallocFailed ) break;
  }
  assert( nErr==0 );
#ifdef YYTRACKMAXSTACKDEPTH
  sqlite3_mutex_enter(sqlite3MallocMutex());
  sqlite3StatusHighwater(SQLITE_STATUS_PARSER_STACK,
      sqlite3ParserStackPeak(pEngine)
  );
  sqlite3_mutex_leave(sqlite3MallocMutex());
#endif /* YYDEBUG */
#ifdef sqlite3Parser_ENGINEALWAYSONSTACK
  sqlite3ParserFinalize(pEngine);
#else
  sqlite3ParserFree(pEngine, sqlite3_free);
#endif
  if( db->mallocFailed ){
    pParse->rc = SQLITE_NOMEM_BKPT;
  }
  if( pParse->rc!=SQLITE_OK && pParse->rc!=SQLITE_DONE && pParse->zErrMsg==0 ){
    pParse->zErrMsg = sqlite3MPrintf(db, "%s", sqlite3ErrStr(pParse->rc));
  }
  assert( pzErrMsg!=0 );
  if( pParse->zErrMsg ){
    *pzErrMsg = pParse->zErrMsg;
    sqlite3_log(pParse->rc, "%s in \"%s\"", 
                *pzErrMsg, pParse->zTail);
    pParse->zErrMsg = 0;
    nErr++;
  }
  pParse->zTail = zSql;
  if( pParse->pVdbe && pParse->nErr>0 && pParse->nested==0 ){
    sqlite3VdbeDelete(pParse->pVdbe);
    pParse->pVdbe = 0;
  }
#ifndef SQLITE_OMIT_SHARED_CACHE
  if( pParse->nested==0 ){
    sqlite3DbFree(db, pParse->aTableLock);
    pParse->aTableLock = 0;
    pParse->nTableLock = 0;
  }
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3_free(pParse->apVtabLock);
#endif

  if( !IN_SPECIAL_PARSE ){
    /* If the pParse->declareVtab flag is set, do not delete any table 
    ** structure built up in pParse->pNewTable. The calling code (see vtab.c)
    ** will take responsibility for freeing the Table structure.
    */
    sqlite3DeleteTable(db, pParse->pNewTable);
  }
  if( !IN_RENAME_OBJECT ){
    sqlite3DeleteTrigger(db, pParse->pNewTrigger);
  }

  if( pParse->pWithToFree ) sqlite3WithDelete(db, pParse->pWithToFree);
  sqlite3DbFree(db, pParse->pVList);
  while( pParse->pAinc ){
    AutoincInfo *p = pParse->pAinc;
    pParse->pAinc = p->pNext;
    sqlite3DbFreeNN(db, p);
  }
  while( pParse->pZombieTab ){
    Table *p = pParse->pZombieTab;
    pParse->pZombieTab = p->pNextZombie;
    sqlite3DeleteTable(db, p);
  }
  assert( nErr==0 || pParse->rc!=SQLITE_OK );
  return nErr;
}


#ifdef SQLITE_ENABLE_NORMALIZE
/*
** Insert a single space character into pStr if the current string
** ends with an identifier
*/
static void addSpaceSeparator(sqlite3_str *pStr){
  if( pStr->nChar && sqlite3IsIdChar(pStr->zText[pStr->nChar-1]) ){
    sqlite3_str_append(pStr, " ", 1);
  }
}

/*
** Compute a normalization of the SQL given by zSql[0..nSql-1].  Return
** the normalization in space obtained from sqlite3DbMalloc().  Or return
** NULL if anything goes wrong or if zSql is NULL.
*/
char *sqlite3Normalize(
  Vdbe *pVdbe,       /* VM being reprepared */
  const char *zSql   /* The original SQL string */
){
  sqlite3 *db;       /* The database connection */
  int i;             /* Next unread byte of zSql[] */
  int n;             /* length of current token */
  int tokenType;     /* type of current token */
  int prevType = 0;  /* Previous non-whitespace token */
  int nParen;        /* Number of nested levels of parentheses */
  int iStartIN;      /* Start of RHS of IN operator in z[] */
  int nParenAtIN;    /* Value of nParent at start of RHS of IN operator */
  int j;             /* Bytes of normalized SQL generated so far */
  sqlite3_str *pStr; /* The normalized SQL string under construction */

  db = sqlite3VdbeDb(pVdbe);
  tokenType = -1;
  nParen = iStartIN = nParenAtIN = 0;
  pStr = sqlite3_str_new(db);
  assert( pStr!=0 );  /* sqlite3_str_new() never returns NULL */
  for(i=0; zSql[i] && pStr->accError==0; i+=n){
    if( tokenType!=TK_SPACE ){
      prevType = tokenType;
    }
    n = sqlite3GetToken((unsigned char*)zSql+i, &tokenType);
    if( NEVER(n<=0) ) break;
    switch( tokenType ){
      case TK_SPACE: {
        break;
      }
      case TK_NULL: {
        if( prevType==TK_IS || prevType==TK_NOT ){
          sqlite3_str_append(pStr, " NULL", 5);
          break;
        }
        /* Fall through */
      }
      case TK_STRING:
      case TK_INTEGER:
      case TK_FLOAT:
      case TK_VARIABLE:
      case TK_BLOB: {
        sqlite3_str_append(pStr, "?", 1);
        break;
      }
      case TK_LP: {
        nParen++;
        if( prevType==TK_IN ){
          iStartIN = pStr->nChar;
          nParenAtIN = nParen;
        }
        sqlite3_str_append(pStr, "(", 1);
        break;
      }
      case TK_RP: {
        if( iStartIN>0 && nParen==nParenAtIN ){
          assert( pStr->nChar>=iStartIN );
          pStr->nChar = iStartIN+1;
          sqlite3_str_append(pStr, "?,?,?", 5);
          iStartIN = 0;
        }
        nParen--;
        sqlite3_str_append(pStr, ")", 1);
        break;
      }
      case TK_ID: {
        iStartIN = 0;
        j = pStr->nChar;
        if( sqlite3Isquote(zSql[i]) ){
          char *zId = sqlite3DbStrNDup(db, zSql+i, n);
          int nId;
          int eType = 0;
          if( zId==0 ) break;
          sqlite3Dequote(zId);
          if( zSql[i]=='"' && sqlite3VdbeUsesDoubleQuotedString(pVdbe, zId) ){
            sqlite3_str_append(pStr, "?", 1);
            sqlite3DbFree(db, zId);
            break;
          }
          nId = sqlite3Strlen30(zId);
          if( sqlite3GetToken((u8*)zId, &eType)==nId && eType==TK_ID ){
            addSpaceSeparator(pStr);
            sqlite3_str_append(pStr, zId, nId);
          }else{
            sqlite3_str_appendf(pStr, "\"%w\"", zId);
          }
          sqlite3DbFree(db, zId);
        }else{
          addSpaceSeparator(pStr);
          sqlite3_str_append(pStr, zSql+i, n);
        }
        while( j<pStr->nChar ){
          pStr->zText[j] = sqlite3Tolower(pStr->zText[j]);
          j++;
        }
        break;
      }
      case TK_SELECT: {
        iStartIN = 0;
        /* fall through */
      }
      default: {
        if( sqlite3IsIdChar(zSql[i]) ) addSpaceSeparator(pStr);
        j = pStr->nChar;
        sqlite3_str_append(pStr, zSql+i, n);
        while( j<pStr->nChar ){
          pStr->zText[j] = sqlite3Toupper(pStr->zText[j]);
          j++;
        }
        break;
      }
    }
  }
  if( tokenType!=TK_SEMI ) sqlite3_str_append(pStr, ";", 1);
  return sqlite3_str_finish(pStr);
}
Esempio n. 8
0
/*
** This routine generates code that opens the sqlite_stat1 table for
** writing with cursor iStatCur. If the library was built with the
** SQLITE_ENABLE_STAT2 macro defined, then the sqlite_stat2 table is
** opened for writing using cursor (iStatCur+1)
**
** If the sqlite_stat1 tables does not previously exist, it is created.
** Similarly, if the sqlite_stat2 table does not exist and the library
** is compiled with SQLITE_ENABLE_STAT2 defined, it is created. 
**
** Argument zWhere may be a pointer to a buffer containing a table name,
** or it may be a NULL pointer. If it is not NULL, then all entries in
** the sqlite_stat1 and (if applicable) sqlite_stat2 tables associated
** with the named table are deleted. If zWhere==0, then code is generated
** to delete all stat table entries.
*/
static void openStatTable(
  Parse *pParse,          /* Parsing context */
  int iDb,                /* The database we are looking in */
  int iStatCur,           /* Open the sqlite_stat1 table on this cursor */
  const char *zWhere,     /* Delete entries for this table or index */
  const char *zWhereType  /* Either "tbl" or "idx" */
){
  static const struct {
    const char *zName;
    const char *zCols;
  } aTable[] = {
    { "sqlite_stat1", "tbl,idx,stat" },
#ifdef SQLITE_ENABLE_STAT2
    { "sqlite_stat2", "tbl,idx,sampleno,sample" },
#endif
  };

  int aRoot[] = {0, 0};
  u8 aCreateTbl[] = {0, 0};

  int i;
  sqlite3 *db = pParse->db;
  Db *pDb;
  Vdbe *v = sqlite3GetVdbe(pParse);
  if( v==0 ) return;
  assert( sqlite3BtreeHoldsAllMutexes(db) );
  assert( sqlite3VdbeDb(v)==db );
  pDb = &db->aDb[iDb];

  for(i=0; i<ArraySize(aTable); i++){
    const char *zTab = aTable[i].zName;
    Table *pStat;
    if( (pStat = sqlite3FindTable(db, zTab, pDb->zName))==0 ){
      /* The sqlite_stat[12] table does not exist. Create it. Note that a 
      ** side-effect of the CREATE TABLE statement is to leave the rootpage 
      ** of the new table in register pParse->regRoot. This is important 
      ** because the OpenWrite opcode below will be needing it. */
      sqlite3NestedParse(pParse,
          "CREATE TABLE %Q.%s(%s)", pDb->zName, zTab, aTable[i].zCols
      );
      aRoot[i] = pParse->regRoot;
      aCreateTbl[i] = 1;
    }else{
      /* The table already exists. If zWhere is not NULL, delete all entries 
      ** associated with the table zWhere. If zWhere is NULL, delete the
      ** entire contents of the table. */
      aRoot[i] = pStat->tnum;
      sqlite3TableLock(pParse, iDb, aRoot[i], 1, zTab);
      if( zWhere ){
        sqlite3NestedParse(pParse,
           "DELETE FROM %Q.%s WHERE %s=%Q", pDb->zName, zTab, zWhereType, zWhere
        );
      }else{
        /* The sqlite_stat[12] table already exists.  Delete all rows. */
        sqlite3VdbeAddOp2(v, OP_Clear, aRoot[i], iDb);
      }
    }
  }

  /* Open the sqlite_stat[12] tables for writing. */
  for(i=0; i<ArraySize(aTable); i++){
    sqlite3VdbeAddOp3(v, OP_OpenWrite, iStatCur+i, aRoot[i], iDb);
    sqlite3VdbeChangeP4(v, -1, (char *)3, P4_INT32);
    sqlite3VdbeChangeP5(v, aCreateTbl[i]);
  }
}