78 lines
2.5 KiB
PHP
78 lines
2.5 KiB
PHP
|
<?php
|
||
|
|
/**
|
||
|
|
* Zend Framework
|
||
|
|
*
|
||
|
|
* LICENSE
|
||
|
|
*
|
||
|
|
* This source file is subject to the new BSD license that is bundled
|
||
|
|
* with this package in the file LICENSE.txt.
|
||
|
|
* It is also available through the world-wide-web at this URL:
|
||
|
|
* http://framework.zend.com/license/new-bsd
|
||
|
|
* If you did not receive a copy of the license and are unable to
|
||
|
|
* obtain it through the world-wide-web, please send an email
|
||
|
|
* to license@zend.com so we can send you a copy immediately.
|
||
|
|
*
|
||
|
|
* @category Zend
|
||
|
|
* @package Zend_Db
|
||
|
|
* @subpackage Expr
|
||
|
|
* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
|
||
|
|
* @license http://framework.zend.com/license/new-bsd New BSD License
|
||
|
|
* @version $Id: Expr.php 16203 2009-06-21 18:56:17Z thomas $
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Class for SQL SELECT fragments.
|
||
|
|
*
|
||
|
|
* This class simply holds a string, so that fragments of SQL statements can be
|
||
|
|
* distinguished from identifiers and values that should be implicitly quoted
|
||
|
|
* when interpolated into SQL statements.
|
||
|
|
*
|
||
|
|
* For example, when specifying a primary key value when inserting into a new
|
||
|
|
* row, some RDBMS brands may require you to use an expression to generate the
|
||
|
|
* new value of a sequence. If this expression is treated as an identifier,
|
||
|
|
* it will be quoted and the expression will not be evaluated. Another example
|
||
|
|
* is that you can use Zend_Db_Expr in the Zend_Db_Select::order() method to
|
||
|
|
* order by an expression instead of simply a column name.
|
||
|
|
*
|
||
|
|
* The way this works is that in each context in which a column name can be
|
||
|
|
* specified to methods of Zend_Db classes, if the value is an instance of
|
||
|
|
* Zend_Db_Expr instead of a plain string, then the expression is not quoted.
|
||
|
|
* If it is a plain string, it is assumed to be a plain column name.
|
||
|
|
*
|
||
|
|
* @category Zend
|
||
|
|
* @package Zend_Db
|
||
|
|
* @subpackage Expr
|
||
|
|
* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
|
||
|
|
* @license http://framework.zend.com/license/new-bsd New BSD License
|
||
|
|
*/
|
||
|
|
class Zend_Db_Expr
|
||
|
|
{
|
||
|
|
/**
|
||
|
|
* Storage for the SQL expression.
|
||
|
|
*
|
||
|
|
* @var string
|
||
|
|
*/
|
||
|
|
protected $_expression;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Instantiate an expression, which is just a string stored as
|
||
|
|
* an instance member variable.
|
||
|
|
*
|
||
|
|
* @param string $expression The string containing a SQL expression.
|
||
|
|
*/
|
||
|
|
public function __construct($expression)
|
||
|
|
{
|
||
|
|
$this->_expression = (string) $expression;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @return string The string of the SQL expression stored in this object.
|
||
|
|
*/
|
||
|
|
public function __toString()
|
||
|
|
{
|
||
|
|
return $this->_expression;
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|