**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.216 2008/01/08 02:57:56 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P4 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................
  char *zTab;           /* Name of the table into which we are inserting */
  const char *zDb;      /* Name of the database holding this table */
  int i, j, idx;        /* Loop counters */
  Vdbe *v;              /* Generate code into this virtual machine */
  Index *pIdx;          /* For looping over indices of the table */
  int nColumn;          /* Number of columns in the data */
  int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
  int base = 0;         /* VDBE Cursor number for pTab */
  int keyColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
  int endOfLoop;        /* Label for the end of the insertion loop */
  int useTempTable = 0; /* Store SELECT results in intermediate table */
  int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
  int iCont=0,iBreak=0; /* Beginning and end of the loop over srcTab */
  int iSelectLoop = 0;  /* Address of code that implements the SELECT */
  int iCleanup = 0;     /* Address of the cleanup code */
................................................................................
  }

  /* If this is not a view, open the table and and all indices */
  if( !isView ){
    int nIdx;
    int i;

    base = pParse->nTab;
    nIdx = sqlite3OpenTableAndIndices(pParse, pTab, base, OP_OpenWrite);
    aRegIdx = sqlite3DbMallocZero(db, sizeof(int)*(nIdx+1));
    if( aRegIdx==0 ){
      goto insert_cleanup;
    }
    for(i=0; i<nIdx; i++){
      aRegIdx[i] = ++pParse->nMem;
    }
................................................................................
      }else{
        VdbeOp *pOp;
        sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, 0);
        pOp = sqlite3VdbeGetOp(v, sqlite3VdbeCurrentAddr(v) - 1);
        if( pOp && pOp->opcode==OP_Null ){
          appendFlag = 1;
          pOp->opcode = OP_NewRowid;
          pOp->p1 = base;
          pOp->p2 = regRowid;
          pOp->p3 = regAutoinc;
        }else{
          /* TODO: Avoid this use of the stack. */
          sqlite3VdbeAddOp2(v, OP_Move, 0, regRowid);
        }
      }
      /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
      ** to generate a unique primary key value.
      */
      if( !appendFlag ){
        sqlite3VdbeAddOp2(v, OP_IfMemNull, regRowid, sqlite3VdbeCurrentAddr(v)+2);
        sqlite3VdbeAddOp2(v, OP_Goto, -1, sqlite3VdbeCurrentAddr(v)+2);
        sqlite3VdbeAddOp3(v, OP_NewRowid, base, regRowid, regAutoinc);
        sqlite3VdbeAddOp3(v, OP_MustBeInt, 0, 0, regRowid);
      }
    }else if( IsVirtual(pTab) ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
    }else{
      sqlite3VdbeAddOp3(v, OP_NewRowid, base, regRowid, regAutoinc);
      appendFlag = 1;
    }
    autoIncStep(pParse, regAutoinc, regRowid);

    /* Push onto the stack, data for all columns of the new entry, beginning
    ** with the first column.
    */
................................................................................
    if( IsVirtual(pTab) ){
      pParse->pVirtualLock = pTab;
      sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns,
                     (const char*)pTab->pVtab, P4_VTAB);
    }else
#endif
    {
      sqlite3RegToStack(pParse, regIns, pTab->nCol+1);
      sqlite3GenerateConstraintChecks(pParse, pTab, base, aRegIdx, keyColumn>=0,








                                     0, onError, endOfLoop);

      sqlite3CompleteInsertion(pParse, pTab, base, aRegIdx,0,0,







                            (triggers_exist & TRIGGER_AFTER)!=0 ? newIdx : -1,
                            appendFlag);

    }
  }

  /* Update the count of rows that are inserted
  */
  if( (db->flags & SQLITE_CountRows)!=0 ){
    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
................................................................................
    sqlite3VdbeAddOp2(v, OP_Pop, nColumn, 0);
    sqlite3VdbeAddOp2(v, OP_Return, 0, 0);
    sqlite3VdbeResolveLabel(v, iCleanup);
  }

  if( !IsVirtual(pTab) && !isView ){
    /* Close all tables opened */
    sqlite3VdbeAddOp2(v, OP_Close, base, 0);
    for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
      sqlite3VdbeAddOp2(v, OP_Close, idx+base, 0);
    }
  }

  /* Update the sqlite_sequence table by storing the content of the
  ** counter value in memory regAutoinc back into the sqlite_sequence
  ** table.
  */
................................................................................
  sqlite3IdListDelete(pColumn);
  sqlite3_free(aRegIdx);
}

/*
** Generate code to do constraint checks prior to an INSERT or an UPDATE.
**
** When this routine is called, the stack contains (from bottom to top)
** the following values:
**
**    1.  The rowid of the row to be updated before the update.  This
**        value is omitted unless we are doing an UPDATE that involves a
**        change to the record number. (Or writing to a virtual table.)
**
**    2.  The rowid of the row after the update.
**
**    3.  The data in the first column of the entry after the update.
**
**    i.  Data from middle columns...
**
**    N.  The data in the last column of the entry after the update.


**
** The old rowid shown as entry (1) above is omitted unless both isUpdate
** and rowidChng are 1.  isUpdate is true for UPDATEs and false for
** INSERTs and rowidChng is true if the record number is being changed.
**
** The code generated by this routine store new index entries into
** registers identified by aRegIdx[].  No index entry is created for
................................................................................
**
** Which action to take is determined by the overrideError parameter.
** Or if overrideError==OE_Default, then the pParse->onError parameter
** is used.  Or if pParse->onError==OE_Default then the onError value
** for the constraint is used.
**
** The calling routine must open a read/write cursor for pTab with
** cursor number "base".  All indices of pTab must also have open
** read/write cursors with cursor number base+i for the i-th cursor.
** Except, if there is no possibility of a REPLACE action then
** cursors do not need to be open for indices where aRegIdx[i]==0.
**
** If the isUpdate flag is true, it means that the "base" cursor is
** initially pointing to an entry that is being updated.  The isUpdate
** flag causes extra code to be generated so that the "base" cursor
** is still pointing at the same entry after the routine returns.
** Without the isUpdate flag, the "base" cursor might be moved.
*/
void sqlite3GenerateConstraintChecks(
  Parse *pParse,      /* The parser context */
  Table *pTab,        /* the table into which we are inserting */
  int base,           /* Index of a read/write cursor pointing at pTab */

  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
  int rowidChng,      /* True if the record number will change */
  int isUpdate,       /* True for UPDATE, False for INSERT */
  int overrideError,  /* Override onError to this if not OE_Default */
  int ignoreDest      /* Jump to this label on an OE_Ignore resolution */
){
  int i;
  Vdbe *v;
  int nCol;
  int onError;
  int j1, j2, j3;     /* Address of jump instructions */

  int iCur;
  Index *pIdx;
  int seenReplace = 0;
  int hasTwoRowids = (isUpdate && rowidChng);

  int regRowid, regData;

  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  nCol = pTab->nCol;


  /* Copy rowids and data into registers 
  */
  regRowid = sqlite3StackToReg(pParse, nCol+1+hasTwoRowids);
  sqlite3RegToStack(pParse, regRowid, nCol+1+hasTwoRowids);
  if( hasTwoRowids ) regRowid++;
  regData = regRowid+1;

  /* Test all NOT NULL constraints.
  */
  for(i=0; i<nCol; i++){
    if( i==pTab->iPKey ){
      continue;
    }
................................................................................
        sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_CONSTRAINT, onError);
        sqlite3SetString(&zMsg, pTab->zName, ".", pTab->aCol[i].zName,
                        " may not be NULL", (char*)0);
        sqlite3VdbeChangeP4(v, -1, zMsg, P4_DYNAMIC);
        break;
      }
      case OE_Ignore: {
        sqlite3VdbeAddOp2(v, OP_Pop, nCol+1+hasTwoRowids, 0);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
      case OE_Replace: {
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, 0);
        sqlite3VdbeAddOp2(v, OP_Copy, 0, regData+i);
        sqlite3VdbeAddOp1(v, OP_Push, nCol-i);
        break;
      }
    }
    sqlite3VdbeJumpHere(v, j1);
  }

  /* Test all CHECK constraints
................................................................................
#ifndef SQLITE_OMIT_CHECK
  if( pTab->pCheck && (pParse->db->flags & SQLITE_IgnoreChecks)==0 ){
    int allOk = sqlite3VdbeMakeLabel(v);
    pParse->ckBase = regData;
    sqlite3ExprIfTrue(pParse, pTab->pCheck, allOk, 1);
    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
    if( onError==OE_Ignore ){
      sqlite3VdbeAddOp2(v, OP_Pop, nCol+1+hasTwoRowids, 0);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
    }else{
      sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_CONSTRAINT, onError);
    }
    sqlite3VdbeResolveLabel(v, allOk);
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */
................................................................................
    }
    
    if( isUpdate ){
      sqlite3VdbeAddOp1(v, OP_SCopy, regRowid-1);
      sqlite3VdbeAddOp1(v, OP_SCopy, regRowid);
      j2 = sqlite3VdbeAddOp2(v, OP_Eq, 0, 0);
    }
    j3 = sqlite3VdbeAddOp3(v, OP_NotExists, base, 0, regRowid);
    switch( onError ){
      default: {
        onError = OE_Abort;
        /* Fall thru into the next case */
      }
      case OE_Rollback:
      case OE_Abort:
      case OE_Fail: {
        sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0,
                         "PRIMARY KEY must be unique", P4_STATIC);
        break;
      }
      case OE_Replace: {
        sqlite3GenerateRowIndexDelete(v, pTab, base, 0);
        if( isUpdate ){
          sqlite3VdbeAddOp1(v, OP_SCopy, regRowid-hasTwoRowids);
          sqlite3VdbeAddOp2(v, OP_MoveGe, base, 0);
        }
        seenReplace = 1;
        break;
      }
      case OE_Ignore: {
        assert( seenReplace==0 );
        sqlite3VdbeAddOp2(v, OP_Pop, nCol+1+hasTwoRowids, 0);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
    }
    sqlite3VdbeJumpHere(v, j3);
    if( isUpdate ){
      sqlite3VdbeJumpHere(v, j2);
      sqlite3VdbeAddOp1(v, OP_SCopy, regRowid-1);
      sqlite3VdbeAddOp2(v, OP_MoveGe, base, 0);
    }
  }

  /* Test all UNIQUE constraints by creating entries for each UNIQUE
  ** index and making sure that duplicate entries do not already exist.
  ** Add the new records to the indices as we go.
  */
................................................................................
      else if( onError==OE_Fail ) onError = OE_Abort;
    }
    

    /* Check to see if the new index entry will be unique */
    sqlite3VdbeAddOp1(v, OP_SCopy, aRegIdx[iCur]);
    sqlite3VdbeAddOp1(v, OP_SCopy, regRowid-hasTwoRowids);
    j3 = sqlite3VdbeAddOp2(v, OP_IsUnique, base+iCur+1, 0);

    /* Generate code that executes if the new index entry is not unique */
    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
        || onError==OE_Ignore || onError==OE_Replace );
    switch( onError ){
      case OE_Rollback:
      case OE_Abort:
................................................................................
        sqlite3_snprintf(sizeof(zErrMsg)-n1, &zErrMsg[n1], 
            pIdx->nColumn>1 ? " are not unique" : " is not unique");
        sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0, zErrMsg,0);
        break;
      }
      case OE_Ignore: {
        assert( seenReplace==0 );
        sqlite3VdbeAddOp2(v, OP_Pop, nCol+3+hasTwoRowids, 0);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
      case OE_Replace: {
        int iRowid = sqlite3StackToReg(pParse, 1);
        sqlite3GenerateRowDelete(pParse->db, v, pTab, base, iRowid, 0);
        if( isUpdate ){
          sqlite3VdbeAddOp1(v, OP_SCopy, regRowid-hasTwoRowids);
          sqlite3VdbeAddOp2(v, OP_MoveGe, base, 0);
        }
        seenReplace = 1;
        break;
      }
    }
    sqlite3VdbeJumpHere(v, j3);
    sqlite3VdbeAddOp1(v, OP_Pop, 1);
................................................................................
#endif
  }
}

/*
** This routine generates code to finish the INSERT or UPDATE operation
** that was started by a prior call to sqlite3GenerateConstraintChecks.
** The stack must contain keys for all active indices followed by data
** and the rowid for the new entry.  This routine creates the new
** entries in all indices and in the main table.
**
** The arguments to this routine should be the same as the first six
** arguments to sqlite3GenerateConstraintChecks.
*/
void sqlite3CompleteInsertion(
  Parse *pParse,      /* The parser context */
  Table *pTab,        /* the table into which we are inserting */
  int base,           /* Index of a read/write cursor pointing at pTab */

  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
  int rowidChng,      /* True if the record number will change */
  int isUpdate,       /* True for UPDATE, False for INSERT */
  int newIdx,         /* Index of NEW table for triggers.  -1 if none */
  int appendBias      /* True if this is likely to be an append */
){
  int i;
  Vdbe *v;
  int nIdx;
  Index *pIdx;
  int pik_flags;


  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){}
  for(i=nIdx-1; i>=0; i--){
    if( aRegIdx[i]==0 ) continue;
    sqlite3VdbeAddOp2(v, OP_IdxInsert, base+i+1, aRegIdx[i]);
  }


  sqlite3VdbeAddOp2(v, OP_MakeRecord, pTab->nCol, 0);
  sqlite3TableAffinityStr(v, pTab);
#ifndef SQLITE_OMIT_TRIGGER
  if( newIdx>=0 ){
    sqlite3VdbeAddOp1(v, OP_Copy, -1);
    sqlite3VdbeAddOp1(v, OP_Copy, -1);
    sqlite3CodeInsert(pParse, newIdx, 0);
  }
#endif
  if( pParse->nested ){
    pik_flags = 0;
  }else{
    pik_flags = OPFLAG_NCHANGE;
    pik_flags |= (isUpdate?OPFLAG_ISUPDATE:OPFLAG_LASTROWID);
  }
  if( appendBias ){
    pik_flags |= OPFLAG_APPEND;
  }
  sqlite3CodeInsert(pParse, base, pik_flags);
  if( !pParse->nested ){
    sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
  }
  
  if( isUpdate && rowidChng ){
    sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
  }
}

/*
** Generate code that will open cursors for a table and for all
** indices of that table.  The "base" parameter is the cursor number used
** for the table.  Indices are opened on subsequent cursors.
**
** Return the number of indices on the table.
*/
int sqlite3OpenTableAndIndices(
  Parse *pParse,   /* Parsing context */
  Table *pTab,     /* Table to be opened */
  int base,        /* Cursor number assigned to the table */
  int op           /* OP_OpenRead or OP_OpenWrite */
){
  int i;
  int iDb;
  Index *pIdx;
  Vdbe *v;

  if( IsVirtual(pTab) ) return 0;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3OpenTable(pParse, base, iDb, pTab, op);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp4(v, op, i+base, pIdx->tnum, iDb,
                      (char*)pKey, P4_KEYINFO_HANDOFF);
    VdbeComment((v, "%s", pIdx->zName));
  }
  if( pParse->nTab<=base+i ){
    pParse->nTab = base+i;
  }
  return i-1;
}


#ifdef SQLITE_TEST
/*

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.217 2008/01/08 18:57:50 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P4 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................
  char *zTab;           /* Name of the table into which we are inserting */
  const char *zDb;      /* Name of the database holding this table */
  int i, j, idx;        /* Loop counters */
  Vdbe *v;              /* Generate code into this virtual machine */
  Index *pIdx;          /* For looping over indices of the table */
  int nColumn;          /* Number of columns in the data */
  int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
  int baseCur = 0;      /* VDBE Cursor number for pTab */
  int keyColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
  int endOfLoop;        /* Label for the end of the insertion loop */
  int useTempTable = 0; /* Store SELECT results in intermediate table */
  int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
  int iCont=0,iBreak=0; /* Beginning and end of the loop over srcTab */
  int iSelectLoop = 0;  /* Address of code that implements the SELECT */
  int iCleanup = 0;     /* Address of the cleanup code */
................................................................................
  }

  /* If this is not a view, open the table and and all indices */
  if( !isView ){
    int nIdx;
    int i;

    baseCur = pParse->nTab;
    nIdx = sqlite3OpenTableAndIndices(pParse, pTab, baseCur, OP_OpenWrite);
    aRegIdx = sqlite3DbMallocZero(db, sizeof(int)*(nIdx+1));
    if( aRegIdx==0 ){
      goto insert_cleanup;
    }
    for(i=0; i<nIdx; i++){
      aRegIdx[i] = ++pParse->nMem;
    }
................................................................................
      }else{
        VdbeOp *pOp;
        sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, 0);
        pOp = sqlite3VdbeGetOp(v, sqlite3VdbeCurrentAddr(v) - 1);
        if( pOp && pOp->opcode==OP_Null ){
          appendFlag = 1;
          pOp->opcode = OP_NewRowid;
          pOp->p1 = baseCur;
          pOp->p2 = regRowid;
          pOp->p3 = regAutoinc;
        }else{
          /* TODO: Avoid this use of the stack. */
          sqlite3VdbeAddOp2(v, OP_Move, 0, regRowid);
        }
      }
      /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
      ** to generate a unique primary key value.
      */
      if( !appendFlag ){
        sqlite3VdbeAddOp2(v, OP_IfMemNull, regRowid, sqlite3VdbeCurrentAddr(v)+2);
        sqlite3VdbeAddOp2(v, OP_Goto, -1, sqlite3VdbeCurrentAddr(v)+2);
        sqlite3VdbeAddOp3(v, OP_NewRowid, baseCur, regRowid, regAutoinc);
        sqlite3VdbeAddOp3(v, OP_MustBeInt, 0, 0, regRowid);
      }
    }else if( IsVirtual(pTab) ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
    }else{
      sqlite3VdbeAddOp3(v, OP_NewRowid, baseCur, regRowid, regAutoinc);
      appendFlag = 1;
    }
    autoIncStep(pParse, regAutoinc, regRowid);

    /* Push onto the stack, data for all columns of the new entry, beginning
    ** with the first column.
    */
................................................................................
    if( IsVirtual(pTab) ){
      pParse->pVirtualLock = pTab;
      sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns,
                     (const char*)pTab->pVtab, P4_VTAB);
    }else
#endif
    {

      sqlite3GenerateConstraintChecks(
          pParse,
          pTab,
          baseCur,
          regIns,
          aRegIdx,
          keyColumn>=0,
          0,
          onError,
          endOfLoop
      );
      sqlite3CompleteInsertion(
          pParse,
          pTab,
          baseCur,
          regIns,
          aRegIdx,
          0,
          0,
          (triggers_exist & TRIGGER_AFTER)!=0 ? newIdx : -1,
          appendFlag
       );
    }
  }

  /* Update the count of rows that are inserted
  */
  if( (db->flags & SQLITE_CountRows)!=0 ){
    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
................................................................................
    sqlite3VdbeAddOp2(v, OP_Pop, nColumn, 0);
    sqlite3VdbeAddOp2(v, OP_Return, 0, 0);
    sqlite3VdbeResolveLabel(v, iCleanup);
  }

  if( !IsVirtual(pTab) && !isView ){
    /* Close all tables opened */
    sqlite3VdbeAddOp2(v, OP_Close, baseCur, 0);
    for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
      sqlite3VdbeAddOp2(v, OP_Close, idx+baseCur, 0);
    }
  }

  /* Update the sqlite_sequence table by storing the content of the
  ** counter value in memory regAutoinc back into the sqlite_sequence
  ** table.
  */
................................................................................
  sqlite3IdListDelete(pColumn);
  sqlite3_free(aRegIdx);
}

/*
** Generate code to do constraint checks prior to an INSERT or an UPDATE.
**
** The input is a range of consecutive registers as follows:

**
**    1.  The rowid of the row to be updated before the update.  This
**        value is omitted unless we are doing an UPDATE that involves a
**        change to the record number. (Or writing to a virtual table.)
**
**    2.  The rowid of the row after the update.
**
**    3.  The data in the first column of the entry after the update.
**
**    i.  Data from middle columns...
**
**    N.  The data in the last column of the entry after the update.
**
** The regRowid parameter is the index of the register containing (2).
**
** The old rowid shown as entry (1) above is omitted unless both isUpdate
** and rowidChng are 1.  isUpdate is true for UPDATEs and false for
** INSERTs and rowidChng is true if the record number is being changed.
**
** The code generated by this routine store new index entries into
** registers identified by aRegIdx[].  No index entry is created for
................................................................................
**
** Which action to take is determined by the overrideError parameter.
** Or if overrideError==OE_Default, then the pParse->onError parameter
** is used.  Or if pParse->onError==OE_Default then the onError value
** for the constraint is used.
**
** The calling routine must open a read/write cursor for pTab with
** cursor number "baseCur".  All indices of pTab must also have open
** read/write cursors with cursor number baseCur+i for the i-th cursor.
** Except, if there is no possibility of a REPLACE action then
** cursors do not need to be open for indices where aRegIdx[i]==0.
**
** If the isUpdate flag is true, it means that the "baseCur" cursor is
** initially pointing to an entry that is being updated.  The isUpdate
** flag causes extra code to be generated so that the "baseCur" cursor
** is still pointing at the same entry after the routine returns.
** Without the isUpdate flag, the "baseCur" cursor might be moved.
*/
void sqlite3GenerateConstraintChecks(
  Parse *pParse,      /* The parser context */
  Table *pTab,        /* the table into which we are inserting */
  int baseCur,        /* Index of a read/write cursor pointing at pTab */
  int regRowid,       /* Index of the range of input registers */
  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
  int rowidChng,      /* True if the rowid will change */
  int isUpdate,       /* True for UPDATE, False for INSERT */
  int overrideError,  /* Override onError to this if not OE_Default */
  int ignoreDest      /* Jump to this label on an OE_Ignore resolution */
){
  int i;
  Vdbe *v;
  int nCol;
  int onError;
  int j1, j2, j3;     /* Address of jump instructions */
  int regData;        /* Register containing first data column */
  int iCur;
  Index *pIdx;
  int seenReplace = 0;
  int hasTwoRowids = (isUpdate && rowidChng);



  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  nCol = pTab->nCol;
  regData = regRowid + 1;








  /* Test all NOT NULL constraints.
  */
  for(i=0; i<nCol; i++){
    if( i==pTab->iPKey ){
      continue;
    }
................................................................................
        sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_CONSTRAINT, onError);
        sqlite3SetString(&zMsg, pTab->zName, ".", pTab->aCol[i].zName,
                        " may not be NULL", (char*)0);
        sqlite3VdbeChangeP4(v, -1, zMsg, P4_DYNAMIC);
        break;
      }
      case OE_Ignore: {

        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
      case OE_Replace: {
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regData+i);


        break;
      }
    }
    sqlite3VdbeJumpHere(v, j1);
  }

  /* Test all CHECK constraints
................................................................................
#ifndef SQLITE_OMIT_CHECK
  if( pTab->pCheck && (pParse->db->flags & SQLITE_IgnoreChecks)==0 ){
    int allOk = sqlite3VdbeMakeLabel(v);
    pParse->ckBase = regData;
    sqlite3ExprIfTrue(pParse, pTab->pCheck, allOk, 1);
    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
    if( onError==OE_Ignore ){

      sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
    }else{
      sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_CONSTRAINT, onError);
    }
    sqlite3VdbeResolveLabel(v, allOk);
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */
................................................................................
    }
    
    if( isUpdate ){
      sqlite3VdbeAddOp1(v, OP_SCopy, regRowid-1);
      sqlite3VdbeAddOp1(v, OP_SCopy, regRowid);
      j2 = sqlite3VdbeAddOp2(v, OP_Eq, 0, 0);
    }
    j3 = sqlite3VdbeAddOp3(v, OP_NotExists, baseCur, 0, regRowid);
    switch( onError ){
      default: {
        onError = OE_Abort;
        /* Fall thru into the next case */
      }
      case OE_Rollback:
      case OE_Abort:
      case OE_Fail: {
        sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0,
                         "PRIMARY KEY must be unique", P4_STATIC);
        break;
      }
      case OE_Replace: {
        sqlite3GenerateRowIndexDelete(v, pTab, baseCur, 0);
        if( isUpdate ){
          sqlite3VdbeAddOp1(v, OP_SCopy, regRowid-hasTwoRowids);
          sqlite3VdbeAddOp2(v, OP_MoveGe, baseCur, 0);
        }
        seenReplace = 1;
        break;
      }
      case OE_Ignore: {
        assert( seenReplace==0 );

        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
    }
    sqlite3VdbeJumpHere(v, j3);
    if( isUpdate ){
      sqlite3VdbeJumpHere(v, j2);
      sqlite3VdbeAddOp1(v, OP_SCopy, regRowid-1);
      sqlite3VdbeAddOp2(v, OP_MoveGe, baseCur, 0);
    }
  }

  /* Test all UNIQUE constraints by creating entries for each UNIQUE
  ** index and making sure that duplicate entries do not already exist.
  ** Add the new records to the indices as we go.
  */
................................................................................
      else if( onError==OE_Fail ) onError = OE_Abort;
    }
    

    /* Check to see if the new index entry will be unique */
    sqlite3VdbeAddOp1(v, OP_SCopy, aRegIdx[iCur]);
    sqlite3VdbeAddOp1(v, OP_SCopy, regRowid-hasTwoRowids);
    j3 = sqlite3VdbeAddOp2(v, OP_IsUnique, baseCur+iCur+1, 0);

    /* Generate code that executes if the new index entry is not unique */
    assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
        || onError==OE_Ignore || onError==OE_Replace );
    switch( onError ){
      case OE_Rollback:
      case OE_Abort:
................................................................................
        sqlite3_snprintf(sizeof(zErrMsg)-n1, &zErrMsg[n1], 
            pIdx->nColumn>1 ? " are not unique" : " is not unique");
        sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, onError, 0, zErrMsg,0);
        break;
      }
      case OE_Ignore: {
        assert( seenReplace==0 );
        sqlite3VdbeAddOp1(v, OP_Pop, 2+hasTwoRowids);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
      case OE_Replace: {
        int iRowid = sqlite3StackToReg(pParse, 1);
        sqlite3GenerateRowDelete(pParse->db, v, pTab, baseCur, iRowid, 0);
        if( isUpdate ){
          sqlite3VdbeAddOp1(v, OP_SCopy, regRowid-hasTwoRowids);
          sqlite3VdbeAddOp2(v, OP_MoveGe, baseCur, 0);
        }
        seenReplace = 1;
        break;
      }
    }
    sqlite3VdbeJumpHere(v, j3);
    sqlite3VdbeAddOp1(v, OP_Pop, 1);
................................................................................
#endif
  }
}

/*
** This routine generates code to finish the INSERT or UPDATE operation
** that was started by a prior call to sqlite3GenerateConstraintChecks.
** A consecutive range of registers starting at regRowid contains the
** rowid and the content to be inserted.

**
** The arguments to this routine should be the same as the first six
** arguments to sqlite3GenerateConstraintChecks.
*/
void sqlite3CompleteInsertion(
  Parse *pParse,      /* The parser context */
  Table *pTab,        /* the table into which we are inserting */
  int baseCur,        /* Index of a read/write cursor pointing at pTab */
  int regRowid,       /* Range of content */
  int *aRegIdx,       /* Register used by each index.  0 for unused indices */
  int rowidChng,      /* True if the record number will change */
  int isUpdate,       /* True for UPDATE, False for INSERT */
  int newIdx,         /* Index of NEW table for triggers.  -1 if none */
  int appendBias      /* True if this is likely to be an append */
){
  int i;
  Vdbe *v;
  int nIdx;
  Index *pIdx;
  int pik_flags;
  int regData;

  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  for(nIdx=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, nIdx++){}
  for(i=nIdx-1; i>=0; i--){
    if( aRegIdx[i]==0 ) continue;
    sqlite3VdbeAddOp2(v, OP_IdxInsert, baseCur+i+1, aRegIdx[i]);
  }
  regData = regRowid + 1;
  sqlite3VdbeAddOp1(v, OP_SCopy, regRowid);
  sqlite3VdbeAddOp2(v, OP_RegMakeRec, regData, pTab->nCol);
  sqlite3TableAffinityStr(v, pTab);
#ifndef SQLITE_OMIT_TRIGGER
  if( newIdx>=0 ){
    sqlite3VdbeAddOp1(v, OP_SCopy, regRowid);
    sqlite3VdbeAddOp1(v, OP_SCopy, -1);
    sqlite3CodeInsert(pParse, newIdx, 0);
  }
#endif
  if( pParse->nested ){
    pik_flags = 0;
  }else{
    pik_flags = OPFLAG_NCHANGE;
    pik_flags |= (isUpdate?OPFLAG_ISUPDATE:OPFLAG_LASTROWID);
  }
  if( appendBias ){
    pik_flags |= OPFLAG_APPEND;
  }
  sqlite3CodeInsert(pParse, baseCur, pik_flags);
  if( !pParse->nested ){
    sqlite3VdbeChangeP4(v, -1, pTab->zName, P4_STATIC);
  }




}

/*
** Generate code that will open cursors for a table and for all
** indices of that table.  The "baseCur" parameter is the cursor number used
** for the table.  Indices are opened on subsequent cursors.
**
** Return the number of indices on the table.
*/
int sqlite3OpenTableAndIndices(
  Parse *pParse,   /* Parsing context */
  Table *pTab,     /* Table to be opened */
  int baseCur,        /* Cursor number assigned to the table */
  int op           /* OP_OpenRead or OP_OpenWrite */
){
  int i;
  int iDb;
  Index *pIdx;
  Vdbe *v;

  if( IsVirtual(pTab) ) return 0;
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  v = sqlite3GetVdbe(pParse);
  assert( v!=0 );
  sqlite3OpenTable(pParse, baseCur, iDb, pTab, op);
  for(i=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp4(v, op, i+baseCur, pIdx->tnum, iDb,
                      (char*)pKey, P4_KEYINFO_HANDOFF);
    VdbeComment((v, "%s", pIdx->zName));
  }
  if( pParse->nTab<=baseCur+i ){
    pParse->nTab = baseCur+i;
  }
  return i-1;
}


#ifdef SQLITE_TEST
/*

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.642 2008/01/08 02:57:56 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** The macro unlikely() is a hint that surrounds a boolean
** expression that is usually false.  Macro likely() surrounds
................................................................................
int sqlite3ExprIsConstantNotJoin(Expr*);
int sqlite3ExprIsConstantOrFunction(Expr*);
int sqlite3ExprIsInteger(Expr*, int*);
int sqlite3IsRowid(const char*);
void sqlite3GenerateRowDelete(sqlite3*, Vdbe*, Table*, int, int, int);
void sqlite3GenerateRowIndexDelete(Vdbe*, Table*, int, int*);
void sqlite3GenerateIndexKey(Vdbe*, Index*, int);
void sqlite3GenerateConstraintChecks(Parse*,Table*,int,int*,int,int,int,int);

void sqlite3CompleteInsertion(Parse*, Table*, int, int*, int, int, int, int);
int sqlite3OpenTableAndIndices(Parse*, Table*, int, int);
void sqlite3BeginWriteOperation(Parse*, int, int);
Expr *sqlite3ExprDup(sqlite3*,Expr*);
void sqlite3TokenCopy(sqlite3*,Token*, Token*);
ExprList *sqlite3ExprListDup(sqlite3*,ExprList*);
SrcList *sqlite3SrcListDup(sqlite3*,SrcList*);
IdList *sqlite3IdListDup(sqlite3*,IdList*);

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.643 2008/01/08 18:57:50 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** The macro unlikely() is a hint that surrounds a boolean
** expression that is usually false.  Macro likely() surrounds
................................................................................
int sqlite3ExprIsConstantNotJoin(Expr*);
int sqlite3ExprIsConstantOrFunction(Expr*);
int sqlite3ExprIsInteger(Expr*, int*);
int sqlite3IsRowid(const char*);
void sqlite3GenerateRowDelete(sqlite3*, Vdbe*, Table*, int, int, int);
void sqlite3GenerateRowIndexDelete(Vdbe*, Table*, int, int*);
void sqlite3GenerateIndexKey(Vdbe*, Index*, int);
void sqlite3GenerateConstraintChecks(Parse*,Table*,int,int,
                                     int*,int,int,int,int);
void sqlite3CompleteInsertion(Parse*, Table*, int, int, int*,int,int,int,int);
int sqlite3OpenTableAndIndices(Parse*, Table*, int, int);
void sqlite3BeginWriteOperation(Parse*, int, int);
Expr *sqlite3ExprDup(sqlite3*,Expr*);
void sqlite3TokenCopy(sqlite3*,Token*, Token*);
ExprList *sqlite3ExprListDup(sqlite3*,ExprList*);
SrcList *sqlite3SrcListDup(sqlite3*,SrcList*);
IdList *sqlite3IdListDup(sqlite3*,IdList*);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.163 2008/01/08 02:57:56 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Forward declaration */
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */
................................................................................
                         ** aXRef[i]==-1 if the i-th column is not changed. */
  int chngRowid;         /* True if the record number is being changed */
  Expr *pRowidExpr = 0;  /* Expression defining the new record number */
  int openAll = 0;       /* True if all indices need to be opened */
  AuthContext sContext;  /* The authorization context */
  NameContext sNC;       /* The name-context to resolve expressions in */
  int iDb;               /* Database containing the table being updated */
  int memCnt = 0;        /* Memory cell used for counting rows changed */
  int mem1;      /* Memory address storing the rowid for next row to update */
  int iRowid;            /* Memory address storing rowids */

#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* Trying to update a view */
  int triggers_exist = 0;      /* True if any row triggers exist */
#endif
  int iBeginAfterTrigger;      /* Address of after trigger program */
  int iEndAfterTrigger;        /* Exit of after trigger program */
................................................................................
  int iEndBeforeTrigger;       /* Exit of before trigger program */
  u32 old_col_mask = 0;        /* Mask of OLD.* columns in use */
  u32 new_col_mask = 0;        /* Mask of NEW.* columns in use */

  int newIdx      = -1;  /* index of trigger "new" temp table       */
  int oldIdx      = -1;  /* index of trigger "old" temp table       */







  sContext.pParse = 0;
  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ){
    goto update_cleanup;
  }
  assert( pTabList->nSrc==1 );

................................................................................
          reg = ++pParse->nMem;
          break;
        }
      }
    }
    aRegIdx[j] = reg;
  }

















  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto update_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, 1, iDb);
  mem1 = ++pParse->nMem;

#ifndef SQLITE_OMIT_VIRTUALTABLE
  /* Virtual tables must be handled separately */
  if( IsVirtual(pTab) ){
    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
                       pWhere);
    pWhere = 0;
................................................................................
  /* Begin the database scan
  */
  pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0);
  if( pWInfo==0 ) goto update_cleanup;

  /* Remember the rowid of every item to be updated.
  */
  iRowid = ++pParse->nMem;
  sqlite3VdbeAddOp2(v, IsVirtual(pTab) ? OP_VRowid : OP_Rowid, iCur, iRowid);
  sqlite3VdbeAddOp2(v, OP_FifoWrite, iRowid, 0);

  /* End the database scan loop.
  */
  sqlite3WhereEnd(pWInfo);

  /* Initialize the count of updated rows
  */
  if( db->flags & SQLITE_CountRows && !pParse->trigStack ){
    memCnt = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, memCnt);
  }

  if( !isView && !IsVirtual(pTab) ){
    /* 
    ** Open every index that needs updating.  Note that if any
    ** index could potentially invoke a REPLACE conflict resolution 
    ** action, then we need to open all indices because we might need
................................................................................
  
  /* Jump back to this point if a trigger encounters an IGNORE constraint. */
  if( triggers_exist ){
    sqlite3VdbeResolveLabel(v, addr);
  }

  /* Top of the update loop */
  addr = sqlite3VdbeAddOp2(v, OP_FifoRead, iRowid, 0);
  sqlite3VdbeAddOp2(v, OP_StackDepth, -1, 0);

  if( triggers_exist ){
    /* Make cursor iCur point to the record that is being updated.
    */
    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, iRowid);

    /* Generate the OLD table
    */
    sqlite3VdbeAddOp2(v, OP_Rowid, iCur, 0);
    if( !old_col_mask ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, 0);
    }else{
................................................................................
    sqlite3CodeInsert(pParse, newIdx, 0);

    sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
    sqlite3VdbeJumpHere(v, iEndBeforeTrigger);
  }

  if( !isView && !IsVirtual(pTab) ){

    /* Loop over every record that needs updating.  We have to load
    ** the old data for each record to be updated because some columns
    ** might not change and we will need to copy the old value.
    ** Also, the old data is needed to delete the old index entries.
    ** So make the cursor point at the old record.
    */
    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, iRowid);
    sqlite3VdbeAddOp2(v, OP_SCopy, iRowid, 0);

    /* If the record number will change, push the record number as it
    ** will be after the update. (The old record number is currently
    ** on top of the stack.)
    */
    if( chngRowid ){
      sqlite3ExprCode(pParse, pRowidExpr, 0);
      sqlite3VdbeAddOp2(v, OP_MustBeInt, 0, 0);
    }

    /* Compute new data for this record.  
    */
    for(i=0; i<pTab->nCol; i++){
      if( i==pTab->iPKey ){
        sqlite3VdbeAddOp2(v, OP_Null, 0, 0);
        continue;
      }
      j = aXRef[i];
      if( j<0 ){
        sqlite3VdbeAddOp2(v, OP_Column, iCur, i);
        sqlite3ColumnDefault(v, pTab, i);
      }else{
        sqlite3ExprCode(pParse, pChanges->a[j].pExpr, 0);
      }
    }

    /* Do constraint checks
    */
    sqlite3GenerateConstraintChecks(pParse, pTab, iCur, aRegIdx, chngRowid, 1,

                                   onError, addr);

    /* Delete the old indices for the current record.
    */
    sqlite3GenerateRowIndexDelete(v, pTab, iCur, aRegIdx);

    /* If changing the record number, delete the old record.
    */
    if( chngRowid ){
      sqlite3VdbeAddOp2(v, OP_Delete, iCur, 0);
    }

    /* Create the new index entries and the new record.
    */
    sqlite3CompleteInsertion(pParse, pTab, iCur, aRegIdx, chngRowid, 1, -1, 0);

  }

  /* Increment the row counter 
  */
  if( db->flags & SQLITE_CountRows && !pParse->trigStack){
    sqlite3VdbeAddOp2(v, OP_AddImm, memCnt, 1);
  }

  /* If there are triggers, close all the cursors after each iteration
  ** through the loop.  The fire the after triggers.
  */
  if( triggers_exist ){
    sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginAfterTrigger);
................................................................................

  /*
  ** Return the number of rows that were changed. If this routine is 
  ** generating code because of a call to sqlite3NestedParse(), do not
  ** invoke the callback function.
  */
  if( db->flags & SQLITE_CountRows && !pParse->trigStack && pParse->nested==0 ){
    sqlite3VdbeAddOp2(v, OP_ResultRow, memCnt, 1);
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", P4_STATIC);
  }

update_cleanup:
  sqlite3AuthContextPop(&sContext);
  sqlite3_free(aRegIdx);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.164 2008/01/08 18:57:50 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Forward declaration */
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */
................................................................................
                         ** aXRef[i]==-1 if the i-th column is not changed. */
  int chngRowid;         /* True if the record number is being changed */
  Expr *pRowidExpr = 0;  /* Expression defining the new record number */
  int openAll = 0;       /* True if all indices need to be opened */
  AuthContext sContext;  /* The authorization context */
  NameContext sNC;       /* The name-context to resolve expressions in */
  int iDb;               /* Database containing the table being updated */




#ifndef SQLITE_OMIT_TRIGGER
  int isView;                  /* Trying to update a view */
  int triggers_exist = 0;      /* True if any row triggers exist */
#endif
  int iBeginAfterTrigger;      /* Address of after trigger program */
  int iEndAfterTrigger;        /* Exit of after trigger program */
................................................................................
  int iEndBeforeTrigger;       /* Exit of before trigger program */
  u32 old_col_mask = 0;        /* Mask of OLD.* columns in use */
  u32 new_col_mask = 0;        /* Mask of NEW.* columns in use */

  int newIdx      = -1;  /* index of trigger "new" temp table       */
  int oldIdx      = -1;  /* index of trigger "old" temp table       */

  /* Register Allocations */
  int regRowCount = 0;   /* A count of rows changed */
  int regOldRowid;       /* The old rowid */
  int regNewRowid;       /* The new rowid */
  int regData;           /* New data for the row */

  sContext.pParse = 0;
  db = pParse->db;
  if( pParse->nErr || db->mallocFailed ){
    goto update_cleanup;
  }
  assert( pTabList->nSrc==1 );

................................................................................
          reg = ++pParse->nMem;
          break;
        }
      }
    }
    aRegIdx[j] = reg;
  }

  /* Allocate a block of register used to store the change record
  ** sent to sqlite3GenerateConstraintChecks().  There are either
  ** one or two registers for holding the rowid.  One rowid register
  ** is used if chngRowid is false and two are used if chngRowid is
  ** true.  Following these are pTab->nCol register holding column
  ** data.
  */
  regOldRowid = regNewRowid = pParse->nMem + 1;
  pParse->nMem += pTab->nCol + 1;
  if( chngRowid ){
    regNewRowid++;
    pParse->nMem++;
  }
  regData = regNewRowid+1;
 

  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto update_cleanup;
  if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
  sqlite3BeginWriteOperation(pParse, 1, iDb);


#ifndef SQLITE_OMIT_VIRTUALTABLE
  /* Virtual tables must be handled separately */
  if( IsVirtual(pTab) ){
    updateVirtualTable(pParse, pTabList, pTab, pChanges, pRowidExpr, aXRef,
                       pWhere);
    pWhere = 0;
................................................................................
  /* Begin the database scan
  */
  pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0, 0);
  if( pWInfo==0 ) goto update_cleanup;

  /* Remember the rowid of every item to be updated.
  */

  sqlite3VdbeAddOp2(v, IsVirtual(pTab) ? OP_VRowid : OP_Rowid,iCur,regOldRowid);
  sqlite3VdbeAddOp2(v, OP_FifoWrite, regOldRowid, 0);

  /* End the database scan loop.
  */
  sqlite3WhereEnd(pWInfo);

  /* Initialize the count of updated rows
  */
  if( db->flags & SQLITE_CountRows && !pParse->trigStack ){
    regRowCount = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
  }

  if( !isView && !IsVirtual(pTab) ){
    /* 
    ** Open every index that needs updating.  Note that if any
    ** index could potentially invoke a REPLACE conflict resolution 
    ** action, then we need to open all indices because we might need
................................................................................
  
  /* Jump back to this point if a trigger encounters an IGNORE constraint. */
  if( triggers_exist ){
    sqlite3VdbeResolveLabel(v, addr);
  }

  /* Top of the update loop */
  addr = sqlite3VdbeAddOp2(v, OP_FifoRead, regOldRowid, 0);
  sqlite3VdbeAddOp2(v, OP_StackDepth, -1, 0);

  if( triggers_exist ){
    /* Make cursor iCur point to the record that is being updated.
    */
    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);

    /* Generate the OLD table
    */
    sqlite3VdbeAddOp2(v, OP_Rowid, iCur, 0);
    if( !old_col_mask ){
      sqlite3VdbeAddOp2(v, OP_Null, 0, 0);
    }else{
................................................................................
    sqlite3CodeInsert(pParse, newIdx, 0);

    sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginBeforeTrigger);
    sqlite3VdbeJumpHere(v, iEndBeforeTrigger);
  }

  if( !isView && !IsVirtual(pTab) ){

    /* Loop over every record that needs updating.  We have to load
    ** the old data for each record to be updated because some columns
    ** might not change and we will need to copy the old value.
    ** Also, the old data is needed to delete the old index entries.
    ** So make the cursor point at the old record.
    */
    sqlite3VdbeAddOp3(v, OP_NotExists, iCur, addr, regOldRowid);


    /* If the record number will change, push the record number as it
    ** will be after the update. (The old record number is currently
    ** on top of the stack.)
    */
    if( chngRowid ){
      sqlite3ExprCode(pParse, pRowidExpr, regNewRowid);
      sqlite3VdbeAddOp3(v, OP_MustBeInt, 0, 0, regNewRowid);
    }

    /* Compute new data for this record.  
    */
    for(i=0; i<pTab->nCol; i++){
      if( i==pTab->iPKey ){
        sqlite3VdbeAddOp2(v, OP_Null, 0, regData+i);
        continue;
      }
      j = aXRef[i];
      if( j<0 ){
        sqlite3VdbeAddOp3(v, OP_Column, iCur, i, regData+i);
        sqlite3ColumnDefault(v, pTab, i);
      }else{
        sqlite3ExprCode(pParse, pChanges->a[j].pExpr, regData+i);
      }
    }

    /* Do constraint checks
    */
    sqlite3GenerateConstraintChecks(pParse, pTab, iCur, regNewRowid,
                                    aRegIdx, chngRowid, 1,
                                    onError, addr);

    /* Delete the old indices for the current record.
    */
    sqlite3GenerateRowIndexDelete(v, pTab, iCur, aRegIdx);

    /* If changing the record number, delete the old record.
    */
    if( chngRowid ){
      sqlite3VdbeAddOp2(v, OP_Delete, iCur, 0);
    }

    /* Create the new index entries and the new record.
    */
    sqlite3CompleteInsertion(pParse, pTab, iCur, regNewRowid, 
                             aRegIdx, chngRowid, 1, -1, 0);
  }

  /* Increment the row counter 
  */
  if( db->flags & SQLITE_CountRows && !pParse->trigStack){
    sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
  }

  /* If there are triggers, close all the cursors after each iteration
  ** through the loop.  The fire the after triggers.
  */
  if( triggers_exist ){
    sqlite3VdbeAddOp2(v, OP_Goto, 0, iBeginAfterTrigger);
................................................................................

  /*
  ** Return the number of rows that were changed. If this routine is 
  ** generating code because of a call to sqlite3NestedParse(), do not
  ** invoke the callback function.
  */
  if( db->flags & SQLITE_CountRows && !pParse->trigStack && pParse->nested==0 ){
    sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
    sqlite3VdbeSetNumCols(v, 1);
    sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows updated", P4_STATIC);
  }

update_cleanup:
  sqlite3AuthContextPop(&sContext);
  sqlite3_free(aRegIdx);

#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file runs all tests.
#
# $Id: quick.test,v 1.67 2007/11/26 13:36:00 drh Exp $

proc lshift {lvar} {
  upvar $lvar l
  set ret [lindex $l 0]
  set l [lrange $l 1 end]
  return $ret
}
................................................................................
  btree4.test
  btree5.test
  btree6.test
  corrupt.test
  crash.test
  crash2.test
  crash3.test

  exclusive3.test
  fts3.test
  fuzz.test
  fuzz_malloc.test
  in2.test
  loadext.test
  mallocAll.test

#    May you do good and not evil.
#    May you find forgiveness for yourself and forgive others.
#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file runs all tests.
#
# $Id: quick.test,v 1.68 2008/01/08 18:57:50 drh Exp $

proc lshift {lvar} {
  upvar $lvar l
  set ret [lindex $l 0]
  set l [lrange $l 1 end]
  return $ret
}
................................................................................
  btree4.test
  btree5.test
  btree6.test
  corrupt.test
  crash.test
  crash2.test
  crash3.test
  crash4.test
  exclusive3.test
  fts3.test
  fuzz.test
  fuzz_malloc.test
  in2.test
  loadext.test
  mallocAll.test