这个解释器，能解释常用的SQL命令。你可以自行添加其他功能。
<?php
class DB_text {
var $conn;
var $classname = "db_text";
var $database;
function on_create() {
}
function connect($database_name) {
$this->database = $database_name;
if(! file_exists($database_name)) {
$this->conn = array();
$this->_close();
}
$fp = fopen($this->database,"r");
$this->conn = unserialize(fread($fp,filesize($this->database)));
fclose($fp);
}
function &query($query) {
if(eregi("select ",$query)) return $this->_select($query);
if(eregi("insert ",$query)) return $this->_insert($query);
if(eregi("delete ",$query)) return $this->_delete($query);
if(eregi("update ",$query)) return $this->_update($query);
return array();
}
function fetch_row(&$result) {
if(list($key,$value) = each($result))
return $value;
return false;
}
function num_rows($result) {
return count($result);
}
/**
* query的辅助函数
*/
function _select($query) {
if(eregi("(order by (.+))",$query,$regs)) {
$order = $regs[2];
$query = eregi_replace($regs[1],"",$query);
}
if(eregi("(group by (.+))",$query,$regs)) {
$group = $regs[2];
$query = eregi_replace($regs[1],"",$query);
}
eregi("select .* from ([0-9a-z_]+) *(where +(.+))?",$query,$regs);
if($regs[3] != "") {
$keys = $this->_where($regs[3],"\$this->conn[$regs[1]]");
while(list($key,$value) = each($keys)) {
$rs[] = $this->conn[$regs[1]][$value];
}
}else {
$rs = $this->conn[$regs[1]];
}
if($order) {
sscanf($order,"%s %s",$key,$type);
if(empty($type)) $type = "asc";
$this->_sort($rs,$key,$type);
}
return $rs;
}
function _insert($query) {
eregi("insert +into +([0-9a-z_]+) *(.+) *values? *(.+)",$query,$regs);