Database_Expression
extends Kohana_Database_Expression
Database expressions can be used to add unescaped SQL fragments to a Database_Query_Builder object.
For example, you can use an expression to generate a column alias:
// SELECT CONCAT(first_name, last_name) AS full_name
$query = DB::select(array(DB::expr('CONCAT(first_name, last_name)'), 'full_name')));
More examples are available on the Query Builder page
Information
This class is a transparent base class for Kohana_Database_Expression
Constants
- None
Properties
Properties
-
protected $_parameters
-
Default value:
NULL
-
protected $_value
-
Default value:
NULL
Methods
public __construct(string $value [, array $parameters = array(0) ] ) (defined in Kohana_Database_Expression)
Sets the expression string.
$expression = new Database_Expression('COUNT(users.id)');
Parameters
- string $value required - Raw SQL expression string
- array $parameters = array(0) - Unquoted parameter values
Return Values
- void
Source Code
public function __construct($value, $parameters = [])
{
// Set the expression string
$this->_value = $value;
$this->_parameters = $parameters;
}
public __toString() (defined in Kohana_Database_Expression)
Return the value of the expression as a string.
echo $expression;
Tags
Return Values
- string
Source Code
public function __toString()
{
return $this->value();
}
public bind(string $param , mixed & $var ) (defined in Kohana_Database_Expression)
Bind a variable to a parameter.
Parameters
- string $param required - Parameter key to replace
- byref mixed $var required - Variable to use
Return Values
- $this
Source Code
public function bind($param, & $var)
{
$this->_parameters[$param] =& $var;
return $this;
}
public compile([ mixed $db = NULL ] ) (defined in Kohana_Database_Expression)
Compile the SQL expression and return it. Replaces any parameters with their given values.
Parameters
- mixed $db = NULL - Database instance or name of instance
Return Values
- string
Source Code
public function compile($db = NULL)
{
if ( ! is_object($db))
{
// Get the database instance
$db = Database::instance($db);
}
$value = $this->value();
if ( ! empty($this->_parameters))
{
// Quote all of the parameter values
$params = array_map([$db, 'quote'], $this->_parameters);
// Replace the values in the expression
$value = strtr($value, $params);
}
return $value;
}
public param(string $param , mixed $value ) (defined in Kohana_Database_Expression)
Set the value of a parameter.
Parameters
- string $param required - Parameter key to replace
- mixed $value required - Value to use
Return Values
- $this
Source Code
public function param($param, $value)
{
$this->_parameters[$param] = $value;
return $this;
}
public parameters(array $params ) (defined in Kohana_Database_Expression)
Add multiple parameter values.
Parameters
- array $params required - List of parameter values
Return Values
- $this
Source Code
public function parameters(array $params)
{
$this->_parameters = $params + $this->_parameters;
return $this;
}
public value() (defined in Kohana_Database_Expression)
Get the expression value as a string.
$sql = $expression->value();
Return Values
- string
Source Code
public function value()
{
return (string) $this->_value;
}
