SQLite

**    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 DELETE FROM statements.
**
** $Id: delete.c,v 1.35 2002/05/23 12:50:18 drh Exp $
*/
#include "sqliteInt.h"


/*
** Given a table name, find the corresponding table and make sure the
** table is writeable.  Generate an error and return NULL if not.  If

*/
void sqliteGenerateRowDelete(
  Vdbe *v,           /* Generate code into this VDBE */
  Table *pTab,       /* Table containing the row to be deleted */
  int base,          /* Cursor number for the table */
  int count          /* Increment the row change counter */
){
  int addr;
  addr = sqliteVdbeAddOp(v, OP_NotExists, base, 0);
  sqliteGenerateRowIndexDelete(v, pTab, base, 0);
  sqliteVdbeAddOp(v, OP_Delete, base, count);
  sqliteVdbeChangeP2(v, addr, sqliteVdbeCurrentAddr(v));
}

/*
** This routine generates VDBE code that causes the deletion of all
** index entries associated with a single row of a single table.
**
** The VDBE must be in a particular state when this routine is called.

**    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 1.41 2002/05/23 12:50:19 drh Exp $
*/
#include "sqliteInt.h"

/*
** Process an UPDATE statement.
*/
void sqliteUpdate(

  */
  if( !row_triggers_exist ){
    int ii;
    sqliteVdbeAddOp(v, OP_ListRewind, 0, 0);
    addr = sqliteVdbeAddOp(v, OP_ListRead, 0, 0);
    sqliteVdbeAddOp(v, OP_Dup, 0, 0);
  }
  sqliteVdbeAddOp(v, OP_NotExists, base, addr);

  /* 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( chngRecno ){
    if( pTab->iPKey<0 || (j = aXRef[pTab->iPKey])<0 ){

  catchsql {
    CREATE TRIGGER tr1 AFTER UPDATE ON sqlite_master BEGIN
       SELECT * FROM sqlite_master;
    END;
  }
} {1 {cannot create trigger on system table: sqlite_master}}

# Check to make sure that a DELETE statement within the body of
# a trigger does not mess up the DELETE that caused the trigger to
# run in the first place.
#
do_test trig_cd-1.10 {
  execsql {
    create table t1(a,b);
    insert into t1 values(1,'a');
    insert into t1 values(2,'b');
    insert into t1 values(3,'c');
    insert into t1 values(4,'d');
    create trigger r1 after delete on t1 for each row begin
      delete from t1 WHERE a=old.a+2;
    end;
    delete from t1 where a in (1,3);
    select * from t1;
    drop table t1;
  }
} {2 b 4 d}
do_test trig_cd-1.11 {
  execsql {
    create table t1(a,b);
    insert into t1 values(1,'a');
    insert into t1 values(2,'b');
    insert into t1 values(3,'c');
    insert into t1 values(4,'d');
    create trigger r1 after update on t1 for each row begin
      delete from t1 WHERE a=old.a+2;
    end;
    update t1 set b='x-' || b where a in (1,3);
    select * from t1;
    drop table t1;
  }
} {1 x-a 2 b 4 d}

finish_test