SQLite

  ** be invoked unless table pTab is a system table. The difference is that
  ** the update-hook is not invoked for rows removed by REPLACE, but the 
  ** pre-update-hook is.
  */ 
  if( pTab->pSelect==0 ){
    sqlite3GenerateRowIndexDelete(pParse, pTab, iCur, 0);
    sqlite3VdbeAddOp2(v, OP_Delete, iCur, (count?OPFLAG_NCHANGE:0));
    sqlite3VdbeChangeP4(v, -1, pTab, P4_TABLE);
  }

  /* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to
  ** handle rows (possibly in other tables) that refer via a foreign key
  ** to the row just deleted. */ 
  sqlite3FkActions(pParse, pTab, 0, iOld);

          );
        }else{
          /* This OP_Delete opcode fires the pre-update-hook only. It does
          ** not modify the b-tree. It is more efficient to let the coming
          ** OP_Insert replace the existing entry than it is to delete the
          ** existing entry and then insert a new one. */
          sqlite3VdbeAddOp2(v, OP_Delete, baseCur, OPFLAG_ISNOOP);
          sqlite3VdbeChangeP4(v, -1, (char *)pTab, P4_TABLE);
          if( pTab->pIndex ){
            sqlite3MultiWrite(pParse);
            sqlite3GenerateRowIndexDelete(pParse, pTab, baseCur, 0);
          }
        }
        seenReplace = 1;
        break;

    pik_flags |= OPFLAG_APPEND;
  }
  if( useSeekResult ){
    pik_flags |= OPFLAG_USESEEKRESULT;
  }
  sqlite3VdbeAddOp3(v, OP_Insert, baseCur, regRec, regRowid);
  if( !pParse->nested ){
    sqlite3VdbeChangeP4(v, -1, (char *)pTab, P4_TABLE);
  }
  sqlite3VdbeChangeP5(v, pik_flags);
}

/*
** Generate code that will open cursors for a table and for all
** indices of that table.  The "baseCur" parameter is the cursor number used

  }else{
    addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
    assert( (pDest->tabFlags & TF_Autoincrement)==0 );
  }
  sqlite3VdbeAddOp2(v, OP_RowData, iSrc, regData);
  sqlite3VdbeAddOp3(v, OP_Insert, iDest, regData, regRowid);
  sqlite3VdbeChangeP5(v, OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND);
  sqlite3VdbeChangeP4(v, -1, (char *)pDest, P4_TABLE);
  sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1);
  for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
    for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
      if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
    }
    assert( pSrcIdx );
    sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);

    */
    assert( regNew==regNewRowid+1 );
    sqlite3VdbeAddOp3(v, OP_Delete, iCur,
        OPFLAG_ISUPDATE | ((hasFK || chngRowid) ? 0 : OPFLAG_ISNOOP),
        regNewRowid
    );
    if( !pParse->nested ){
      sqlite3VdbeChangeP4(v, -1, pTab, P4_TABLE);
    }
    sqlite3VdbeJumpHere(v, j1);

    if( hasFK ){
      sqlite3FkCheck(pParse, pTab, 0, regNewRowid);
    }
  

** that boosts performance by avoiding redundant seeks.
**
** If the OPFLAG_ISUPDATE flag is set, then this opcode is part of an
** UPDATE operation.  Otherwise (if the flag is clear) then this opcode
** is part of an INSERT operation.  The difference is only important to
** the update hook.
**
** Parameter P4 may point to a Table structure, or may be NULL. If it is 
** not NULL, then the update-hook (sqlite3.xUpdateCallback) is invoked 
** following a successful insert.
**
** (WARNING/TODO: If P1 is a pseudo-cursor and P2 is dynamically
** allocated, then ownership of P2 is transferred to the pseudo-cursor
** and register P2 becomes ephemeral.  If the cursor is changed, the
** value of register P2 will then change.  Make sure this does not
** cause any problems.)
**

  Mem *pData;       /* MEM cell holding data for the record to be inserted */
  Mem *pKey;        /* MEM cell holding key  for the record */
  i64 iKey;         /* The integer ROWID or key for the record to be inserted */
  VdbeCursor *pC;   /* Cursor to table into which insert is written */
  int nZero;        /* Number of zero-bytes to append */
  int seekResult;   /* Result of prior seek or 0 if no USESEEKRESULT flag */
  const char *zDb;  /* database name - used by the update hook */
  Table *pTab;      /* Table structure - used by update and pre-update hooks */
  int op;           /* Opcode for update hook: SQLITE_UPDATE or SQLITE_INSERT */

  pData = &aMem[pOp->p2];
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( memIsValid(pData) );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->pCursor!=0 );
  assert( pC->pseudoTableReg==0 );
  assert( pC->isTable );
  assert( pOp->p4type==P4_TABLE || pOp->p4type==P4_NOTUSED );
  REGISTER_TRACE(pOp->p2, pData);

  if( pOp->opcode==OP_Insert ){
    pKey = &aMem[pOp->p3];
    assert( pKey->flags & MEM_Int );
    assert( memIsValid(pKey) );
    REGISTER_TRACE(pOp->p3, pKey);
    iKey = pKey->u.i;
  }else{
    assert( pOp->opcode==OP_InsertInt );
    iKey = pOp->p3;
  }

  if( pOp->p4type==P4_TABLE && (db->xPreUpdateCallback||db->xUpdateCallback) ){
    assert( pC->isTable );
    assert( pC->iDb>=0 );
    zDb = db->aDb[pC->iDb].zName;
    pTab = pOp->p4.pTab;
    op = ((pOp->p5 & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_INSERT);
  }

  /* Invoke the pre-update hook, if any */
  if( db->xPreUpdateCallback 
   && pOp->p4type==P4_TABLE
   && (!(pOp->p5 & OPFLAG_ISUPDATE) || pC->rowidIsValid==0)
  ){
    sqlite3VdbePreUpdateHook(p, pC, SQLITE_INSERT, zDb, pTab, iKey, pOp->p2);
  }

  if( pOp->p5 & OPFLAG_NCHANGE ) p->nChange++;
  if( pOp->p5 & OPFLAG_LASTROWID ) db->lastRowid = iKey;
  if( pData->flags & MEM_Null ){
    pData->z = 0;
    pData->n = 0;

  );
  pC->rowidIsValid = 0;
  pC->deferredMoveto = 0;
  pC->cacheStatus = CACHE_STALE;

  /* Invoke the update-hook if required. */
  if( rc==SQLITE_OK && db->xUpdateCallback && pOp->p4.z ){
    db->xUpdateCallback(db->pUpdateArg, op, zDb, pTab->zName, iKey);
  }
  break;
}

/* Opcode: Delete P1 P2 P3 P4 *
**
** Delete the record at which the P1 cursor is currently pointing.
**
** The cursor will be left pointing at either the next or the previous
** record in the table. If it is left pointing at the next record, then
** the next Next instruction will be a no-op.  Hence it is OK to delete
** a record from within an Next loop.
**
** If the OPFLAG_NCHANGE flag of P2 is set, then the row change count is
** incremented (otherwise not).
**
** P1 must not be pseudo-table.  It has to be a real table with
** multiple rows.
**
** If P4 is not NULL then it points to a Table struture. In this case either 
** the update or pre-update hook, or both, may be invoked. The P1 cursor must
** have been positioned using OP_NotFound prior to invoking this opcode in 
** this case. Specifically, if one is configured, the pre-update hook is 
** invoked if P4 is not NULL. The update-hook is invoked if one is configured, 
** P4 is not NULL, and the OPFLAG_NCHANGE flag is set in P2.
**
** If the OPFLAG_ISUPDATE flag is set in P2, then P3 contains the address
** of the memory cell that contains the value that the rowid of the row will
** be set to by the update.
*/
case OP_Delete: {
  i64 iKey;
  VdbeCursor *pC;
  const char *zDb;
  Table *pTab;
  int opflags;

  opflags = pOp->p2;
  iKey = 0;
  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
  assert( pC->pCursor!=0 );  /* Only valid for real tables, no pseudotables */
  assert( pOp->p4type==P4_TABLE || pOp->p4type==P4_NOTUSED );

  /* The OP_Delete opcode always follows an OP_NotExists or OP_Last or
  ** OP_Column on the same table without any intervening operations that
  ** might move or invalidate the cursor.  Hence cursor pC is always pointing
  ** to the row to be deleted and the sqlite3VdbeCursorMoveto() operation
  ** below is always a no-op and cannot fail.  We will run it anyhow, though,
  ** to guard against future changes to the code generator.

  */
  if( pOp->p4.z && (db->xPreUpdateCallback || db->xUpdateCallback) ){
    assert( pC->iDb>=0 );
    assert( pC->isTable );
    assert( pC->rowidIsValid );  /* lastRowid set by previous OP_NotFound */
    iKey = pC->lastRowid;
    zDb = db->aDb[pC->iDb].zName;
    pTab = pOp->p4.pTab;
  }

  /* Invoke the pre-update-hook if required. */
  if( db->xPreUpdateCallback && pOp->p4.z ){
    assert( !(opflags & OPFLAG_ISUPDATE) || (aMem[pOp->p3].flags & MEM_Int) );
    sqlite3VdbePreUpdateHook(p, pC,
        (opflags & OPFLAG_ISUPDATE) ? SQLITE_UPDATE : SQLITE_DELETE, 
        zDb, pTab, iKey,
        pOp->p3
    );
  }

  if( opflags & OPFLAG_ISNOOP ) break;

  sqlite3BtreeSetCachedRowid(pC->pCursor, 0);
  rc = sqlite3BtreeDelete(pC->pCursor);
  pC->cacheStatus = CACHE_STALE;

  /* Update the change-counter and invoke the update-hook if required. */
  if( opflags & OPFLAG_NCHANGE ){
    p->nChange++;
    assert( pOp->p4.z );
    if( rc==SQLITE_OK && db->xUpdateCallback ){
      db->xUpdateCallback(db->pUpdateArg, SQLITE_DELETE, zDb, pTab->zName,iKey);
    }
  }
  break;
}
/* Opcode: ResetCount * * * * *
**
** The value of the change counter is copied to the database handle

    VdbeFunc *pVdbeFunc;   /* Used when p4type is P4_VDBEFUNC */
    CollSeq *pColl;        /* Used when p4type is P4_COLLSEQ */
    Mem *pMem;             /* Used when p4type is P4_MEM */
    VTable *pVtab;         /* Used when p4type is P4_VTAB */
    KeyInfo *pKeyInfo;     /* Used when p4type is P4_KEYINFO */
    int *ai;               /* Used when p4type is P4_INTARRAY */
    SubProgram *pProgram;  /* Used when p4type is P4_SUBPROGRAM */
    Table *pTab;           /* Used when p4type is P4_TABLE */
  } p4;
#ifdef SQLITE_DEBUG
  char *zComment;          /* Comment to improve readability */
#endif
#ifdef VDBE_PROFILE
  int cnt;                 /* Number of times this instruction was executed */
  u64 cycles;              /* Total time spent executing this instruction */

#define P4_VTAB     (-10) /* P4 is a pointer to an sqlite3_vtab structure */
#define P4_MPRINTF  (-11) /* P4 is a string obtained from sqlite3_mprintf() */
#define P4_REAL     (-12) /* P4 is a 64-bit floating point value */
#define P4_INT64    (-13) /* P4 is a 64-bit signed integer */
#define P4_INT32    (-14) /* P4 is a 32-bit signed integer */
#define P4_INTARRAY (-15) /* P4 is a vector of 32-bit integers */
#define P4_SUBPROGRAM  (-18) /* P4 is a pointer to a SubProgram structure */
#define P4_TABLE    (-19) /* P4 is a pointer to a Table structure */

/* When adding a P4 argument using P4_KEYINFO, a copy of the KeyInfo structure
** is made.  That copy is freed when the Vdbe is finalized.  But if the
** argument is P4_KEYINFO_HANDOFF, the passed in pointer is used.  It still
** gets freed when the Vdbe is finalized so it still should be obtained
** from a single sqliteMalloc().  But no copy is made and the calling
** function should *not* try to free the KeyInfo.

  VdbeCursor *pCsr;               /* Cursor to read old values from */
  int op;                         /* One of SQLITE_INSERT, UPDATE, DELETE */
  u8 *aRecord;                    /* old.* database record */
  KeyInfo keyinfo;
  UnpackedRecord *pUnpacked;      /* Unpacked version of aRecord[] */
  UnpackedRecord *pNewUnpacked;   /* Unpacked version of new.* record */
  int iNewReg;                    /* Register for new.* values */
  i64 iKey1;                      /* First key value passed to hook */
  i64 iKey2;                      /* Second key value passed to hook */
  int iPKey;                      /* If not negative index of IPK column */
  Mem *aNew;                      /* Array of new.* values */
};

/*
** Function prototypes
*/
void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*);

const char *sqlite3OpcodeName(int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);
void sqlite3VdbeMemStoreType(Mem *pMem);
void sqlite3VdbePreUpdateHook(
    Vdbe *, VdbeCursor *, int, const char*, Table *, i64, int);

#ifdef SQLITE_DEBUG
void sqlite3VdbeMemPrepareToChange(Vdbe*,Mem*);
#endif

#ifndef SQLITE_OMIT_FOREIGN_KEY
int sqlite3VdbeCheckFk(Vdbe *, int);

    p->aRecord = aRecord;
  }

  if( iIdx>=p->pUnpacked->nField ){
    *ppValue = (sqlite3_value *)columnNullValue();
  }else{
    *ppValue = &p->pUnpacked->aMem[iIdx];
    if( iIdx==p->iPKey ){
      sqlite3VdbeMemSetInt64(*ppValue, p->iKey1);
    }
    sqlite3VdbeMemStoreType(*ppValue);
  }

 preupdate_old_out:
  sqlite3Error(db, rc, 0);
  return sqlite3ApiExit(db, rc);
}

      }
      p->pNewUnpacked = pUnpack;
    }
    if( iIdx>=pUnpack->nField ){
      pMem = (sqlite3_value *)columnNullValue();
    }else{
      pMem = &pUnpack->aMem[iIdx];
      if( iIdx==p->iPKey ){
        sqlite3VdbeMemSetInt64(pMem, p->iKey2);
      }
      sqlite3VdbeMemStoreType(pMem);
    }
  }else{
    /* For an UPDATE, memory cell (p->iNewReg+1+iIdx) contains the required
    ** value. Make a copy of the cell contents and return a pointer to it.
    ** It is not safe to return a pointer to the memory cell itself as the
    ** caller may modify the value text encoding.
    */
    assert( p->op==SQLITE_UPDATE );
    if( !p->aNew ){
      p->aNew = (Mem *)sqlite3DbMallocZero(db, sizeof(Mem) * p->pCsr->nField);
      if( !p->aNew ){
        rc = SQLITE_NOMEM;
        goto preupdate_new_out;
      }
    }
    assert( iIdx>=0 && iIdx<p->pCsr->nField );
    pMem = &p->aNew[iIdx];
    if( pMem->flags==0 ){
      if( iIdx==p->iPKey ){
        sqlite3VdbeMemSetInt64(pMem, p->iKey2);
      }else{
        rc = sqlite3VdbeMemCopy(pMem, &p->v->aMem[p->iNewReg+1+iIdx]);
        if( rc!=SQLITE_OK ) goto preupdate_new_out;
      }
      sqlite3VdbeMemStoreType(pMem);
    }
  }
  *ppValue = pMem;

 preupdate_new_out:
  sqlite3Error(db, rc, 0);
  return sqlite3ApiExit(db, rc);
}

** the required value will be read from the row the cursor points to.
*/
void sqlite3VdbePreUpdateHook(
  Vdbe *v,                        /* Vdbe pre-update hook is invoked by */
  VdbeCursor *pCsr,               /* Cursor to grab old.* values from */
  int op,                         /* SQLITE_INSERT, UPDATE or DELETE */
  const char *zDb,                /* Database name */
  Table *pTab,                    /* Modified table */
  i64 iKey1,                      /* Initial key value */
  int iReg                        /* Register for new.* record */
){
  sqlite3 *db = v->db;
  i64 iKey2;
  PreUpdate preupdate;
  const char *zTbl = pTab->zName;

  assert( db->pPreUpdate==0 );
  memset(&preupdate, 0, sizeof(PreUpdate));
  if( op==SQLITE_UPDATE ){
    iKey2 = v->aMem[iReg].u.i;
  }else{
    iKey2 = iKey1;
  }

  preupdate.v = v;
  preupdate.pCsr = pCsr;
  preupdate.op = op;
  preupdate.iNewReg = iReg;
  preupdate.keyinfo.db = db;
  preupdate.keyinfo.enc = ENC(db);
  preupdate.keyinfo.nField = pCsr->nField;
  preupdate.iKey1 = iKey1;
  preupdate.iKey2 = iKey2;
  preupdate.iPKey = pTab->iPKey;

  db->pPreUpdate = &preupdate;
  db->xPreUpdateCallback(db->pPreUpdateArg, db, op, zDb, zTbl, iKey1, iKey2);
  db->pPreUpdate = 0;
  sqlite3DbFree(db, preupdate.aRecord);
  if( preupdate.pUnpacked ){
    sqlite3VdbeDeleteUnpackedRecord(preupdate.pUnpacked);
  }

do_execsql_test 7.5.2.0 {
  CREATE TABLE t8(a, b);
  INSERT INTO t8 VALUES('one', 'two');
  INSERT INTO t8 VALUES('three', 'four');
  ALTER TABLE t8 ADD COLUMN c DEFAULT 'xxx';
}

# At time of writing, these two are broken. They demonstrate that the
# sqlite3_preupdate_old() method does not handle the case where ALTER TABLE
# has been used to add a column with a default value other than NULL.
#
do_preupdate_test 7.5.2.1 {
  DELETE FROM t8 WHERE a = 'one'
} {
  DELETE main t8 1 1   one two xxx
}
do_preupdate_test 7.5.2.2 {
  UPDATE t8 SET b = 'five'
} {
  UPDATE main t8 2 2   three four xxx  three five xxx
}

# This block of tests verifies that IPK values are correctly reported
# by the sqlite3_preupdate_old() and sqlite3_preupdate_new() functions.
#
do_execsql_test 7.6.1 { CREATE TABLE t9(a, b INTEGER PRIMARY KEY, c) }
do_preupdate_test 7.6.2 {
  INSERT INTO t9 VALUES(1, 2, 3);
  UPDATE t9 SET b = b+1, c = c+1;
  DELETE FROM t9 WHERE a = 1;
} {
  INSERT main t9 2 2   1 2 3
  UPDATE main t9 2 3   1 2 3   1 3 4
  DELETE main t9 3 3   1 3 4
}


finish_test