SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.345 2008/01/13 19:02:11 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**

/*
** Generate code that will evaluate expression pExpr and store the
** results in register target.  The results are guaranteed to appear
** in register target.
*/
int sqlite3ExprCode(Parse *pParse, Expr *pExpr, int target){
  int inReg = sqlite3ExprCodeTarget(pParse, pExpr, target);
  assert( pParse->pVdbe || pParse->db->mallocFailed );
  if( inReg!=target && pParse->pVdbe ){
    sqlite3VdbeAddOp2(pParse->pVdbe, (inReg>0 ? OP_SCopy : OP_Move), 
                      inReg, target);
  }
  return target;
}

/*

**    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 SELECT statements in SQLite.
**
** $Id: select.c,v 1.401 2008/01/13 19:02:11 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.

      **     index or indices to use) should place a different priority on 
      **     satisfying the 'ORDER BY' clause than it does in other cases.
      **     Refer to code and comments in where.c for details.
      */
      flag = minMaxQuery(pParse, p);
      if( flag ){
        pMinMax = sqlite3ExprListDup(db, p->pEList->a[0].pExpr->pList);
        if( pMinMax && !db->mallocFailed ){
          pMinMax->a[0].sortOrder = ((flag==ORDERBY_MIN)?0:1);
          pMinMax->a[0].pExpr->op = TK_COLUMN;
          pDel = pMinMax;
        }
      }

      /* This case runs if the aggregate has no GROUP BY clause.  The

  int oldIdx,          /* The indice of the "old" row to access */
  int orconf,          /* ON CONFLICT policy */
  int ignoreJump,      /* Instruction to jump to for RAISE(IGNORE) */
  u32 *piOldColMask,   /* OUT: Mask of columns used from the OLD.* table */
  u32 *piNewColMask    /* OUT: Mask of columns used from the NEW.* table */
){
  Trigger *p;
  sqlite3 *db = pParse->db;
  TriggerStack trigStackEntry;

  trigStackEntry.oldColMask = 0;
  trigStackEntry.newColMask = 0;

  assert(op == TK_UPDATE || op == TK_INSERT || op == TK_DELETE);
  assert(tr_tm == TRIGGER_BEFORE || tr_tm == TRIGGER_AFTER );

  assert(newIdx != -1 || oldIdx != -1);

  for(p=pTab->pTrigger; p; p=p->pNext){
    int fire_this = 0;


    /* Determine whether we should code this trigger */
    if( 
      p->op==op && 
      p->tr_tm==tr_tm && 
      (p->pSchema==p->pTabSchema || p->pSchema==db->aDb[1].pSchema) &&
      (op!=TK_UPDATE||!p->pColumns||checkColumnOverLap(p->pColumns,pChanges))

      int endTrigger;
      Expr * whenExpr;
      AuthContext sContext;
      NameContext sNC;

#ifndef SQLITE_OMIT_TRACE
      sqlite3VdbeAddOp4(pParse->pVdbe, OP_Trace, 0, 0, 0,
                        sqlite3MPrintf(db, "-- TRIGGER %s", p->name),
                        P4_DYNAMIC);
#endif
      memset(&sNC, 0, sizeof(sNC));
      sNC.pParse = pParse;

      /* Push an entry on to the trigger stack */
      trigStackEntry.pTrigger = p;