/**
* 构造最终查询语句
*
* @return string
*/
public function __toString()
{
switch ($this->_sqlPreBuild['action']) {
case Db::SELECT:
return $this->_adapter->parseSelect($this->_sqlPreBuild);
case Db::INSERT:
return 'INSERT INTO ' . $this->_sqlPreBuild['table'] . '(' . implode(' , ', array_keys($this->_sqlPreBuild['rows'])) . ')' . ' VALUES ' . '(' . implode(' , ', array_values($this->_sqlPreBuild['rows'])) . ')' . $this->_sqlPreBuild['limit'];
case Db::DELETE:
return 'DELETE FROM ' . $this->_sqlPreBuild['table'] . $this->_sqlPreBuild['where'];
case Db::UPDATE:
$columns = array();
if (isset($this->_sqlPreBuild['rows'])) {
foreach ($this->_sqlPreBuild['rows'] as $key => $val) {
$columns[] = "{$key} = {$val}";
}
}
return 'UPDATE ' . $this->_sqlPreBuild['table'] . ' SET ' . implode(' , ', $columns) . $this->_sqlPreBuild['where'];
default:
return NULL;
}
}
