自己手工做一个SQL解释器

",$search);
    $search = eregi_replace(" = "," == ",$search);
    $ar = split(" ",$search);
    eval("\$t=$table;");

    for($i=0;$i<count($ar);$i++) {
      if(isset($t[0][$ar[$i]]))
        $ar[$i] = "\$value[".$ar][$i]."]";
    }
    $expr = "\$expl=(".join(" ",$ar).");";
   
    while(list($key,$value) = each($t)) {
      eval($expr);
      if($expl)
        $keys[] = $key;
    }
    return $keys;
  }
  function _sort(&$ar,$key=0,$mode="desc") {
    global $cmp_key;
    $cmp_key = $key;
    if($mode == "asc")
      usort($ar,_cmp_asc);
    else
      usort($ar,_cmp_desc);
  }
  function _close() {
    $fp = fopen($this->database,"w");
    fwrite($fp,serialize($this->conn));
    fclose($fp);
  }
}

/** 排序键
*/
$cmp_key = "";

/** 排序用工作函数(降序 由usort()调用)
*/
function _cmp_desc($a,$b) {
  global $cmp_key;
  if ($a[$cmp_key] == $b[$cmp_key]) return 0;
  return ($a[$cmp_key] > $b[$cmp_key]) ? -1 : 1;
}

/** 排序用工作函数(升序 由usort()调用)
*/
function _cmp_asc($a,$b) {
  global $cmp_key;
  if ($a[$cmp_key] == $b[$cmp_key]) return 0;
  return ($a[$cmp_key] > $b[$cmp_key]) ? 1 : -1;
}
?>

测试例：
<pre>
<?php
//require_once "db_text.php";

$conn = new DB_text;
$conn->connect("text1.txt");

$conn->query("insert into manage (id,title) values (10,'abcd')");
$conn->query("insert into manage (id,title) values (2,'43d')");
$conn->query("insert into manage (id,title) values (20,'tuu')");
$conn->query("update manage set id=101,test='a' where id=10");
//$conn->query("delete from manage where id='10'");
//$conn->query("delete from manage where id=10 or table='code'");


//$rt = $conn->query("select * from manage where id=101 or table='code' group by 1 order by 1 asc");
$rt = $conn->query("select * from manage group by 1 order by id desc");

print_r($rt);

?>
</pre>

关键词：自己手工做一个SQL解释器