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Overview
Comment:Add comments to sqlite3ExprCompare() to clarify its operation. Ticket #2216. (CVS 3663)
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SHA1: fba0a1e50820677081bc7cf01f97bf953065f7c4
User & Date: drh 2007-02-24 15:29:04
Context
2007-02-27
02:01
Improvements to OS layer tracing on the unix backend. (CVS 3664) check-in: 3ad96dbe user: drh tags: trunk
2007-02-24
15:29
Add comments to sqlite3ExprCompare() to clarify its operation. Ticket #2216. (CVS 3663) check-in: fba0a1e5 user: drh tags: trunk
15:18
Additional test cases added. Improvements to the INSERT transfer optimization. (CVS 3662) check-in: 2bf5475b user: drh tags: trunk
Changes
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Changes to src/expr.c.

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**    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 1.279 2007/02/24 13:53:05 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
  }
  pParse->ckOffset = ckOffset;
}

/*
** Do a deep comparison of two expression trees.  Return TRUE (non-zero)
** if they are identical and return FALSE if they differ in any way.










*/
int sqlite3ExprCompare(Expr *pA, Expr *pB){
  int i;
  if( pA==0||pB==0 ){
    return pB==pA;
  }
  if( pA->op!=pB->op ) return 0;







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**    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 1.280 2007/02/24 15:29:04 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
  }
  pParse->ckOffset = ckOffset;
}

/*
** Do a deep comparison of two expression trees.  Return TRUE (non-zero)
** if they are identical and return FALSE if they differ in any way.
**
** Sometimes this routine will return FALSE even if the two expressions
** really are equivalent.  If we cannot prove that the expressions are
** identical, we return FALSE just to be safe.  So if this routine
** returns false, then you do not really know for certain if the two
** expressions are the same.  But if you get a TRUE return, then you
** can be sure the expressions are the same.  In the places where
** this routine is used, it does not hurt to get an extra FALSE - that
** just might result in some slightly slower code.  But returning
** an incorrect TRUE could lead to a malfunction.
*/
int sqlite3ExprCompare(Expr *pA, Expr *pB){
  int i;
  if( pA==0||pB==0 ){
    return pB==pA;
  }
  if( pA->op!=pB->op ) return 0;