====== Criteria ======

Criteria is a group of classes that allows you to build complex conditions for SQL queries using nice OO interface. The initial conception was adopted from [[http://propel.phpdb.org|Propel]] and later was a bit simplified.

==== UML Static Structure ====

{{{ limb:architecture:limb3.0_dbal_criteria.png }}}

==== Criteria classes ====

All criteria classes are children of lmbSQLBaseCriteria class that implements basic functionality to allow a composition of criteria.

^Class name^Description^
|[[lmbSQLRawCriteria]]|Allows to insert a condition into SQL query as is.|
|[[lmbSQLFieldCriteria]]|Allows to insert a condition on some field.|
|[[lmbSQLTableFieldCriteria]]|A child class of lmbSQLFieldCriteria. Requeres explicit table name.|
|[[SQLFielBetweenCriteria]]|Allows to insert between conditions into SQL query.|
|[[lmbSQLFalseCriteria]]|Critetia that is never passed.|
|[[lmbSQLTrueCriteria]]|Criteria that is always passed.|

==== Criteria usage ====

Criteria are commonly used with [[lmbSelectQuery]] class to insert conditions into %where% and %having% placeholders. 

Here is how [[lmbSQLFieldCriteria]] is used:
<code php>
$query->addCondition(newSQLFieldCriteria('name', '%'.$name.'%', lmbSQLFieldCriteria :: LIKE));
</code>

It's possible to combine criteria objects:
<code php>
    $criteria = new lmbSQLTableFieldCriteria('ingredient.name', '%'.$name.'%', lmbSQLFieldCriteria :: LIKE);
    $new_criteria = new lmbSQLTableFieldCriteria('ingredient.name', '%'.$name.'%', lmbSQLFieldCriteria :: LIKE);
    $criteria->addOr($new_criteria);
    $criteria->addAnd(new SQLFielBetweenCriteria('value', 10, 20));
    $query->addCondition($criteria);
</code>