Db/Expr.php
- category
- Zend
- copyright
- Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
- license
- http://framework.zend.com/license/new-bsd New BSD License
- package
- Zend_Db
- subpackage
- Expr
- version
- $Id: Expr.php 20096 2010-01-06 02:05:09Z bkarwin $
- Classes
- Zend_Db_Expr
Description
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.
Zend_Db_Expr
- category
- Zend
- copyright
- Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
- license
- http://framework.zend.com/license/new-bsd New BSD License
- package
- Zend_Db
- subpackage
- Expr
- Properties
- $_expression
- Methods
- __construct
- __toString
Description
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.
Properties
$_expression
string $_expression = ''Storage for the SQL expression.
Details
- $_expression
- string
- visibility
- protected
- default
- final
- false
- static
- false
Methods
__construct
__construct(
string $expression
)
:
Instantiate an expression, which is just a string stored as an instance member variable.
Arguments
- $expression
- string
The string containing a SQL expression.
Details
- visibility
- public
- final
- false
- static
- false
__toString
__toString(
)
:
string
Output
- string
- The string of the SQL expression stored in this object.
Details
- visibility
- public
- final
- false
- static
- false