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mirror of synced 2025-01-17 22:11:41 +03:00
This commit is contained in:
zYne 2007-09-01 22:35:43 +00:00
parent cb50a932fc
commit 4b87106aac
3 changed files with 41 additions and 6 deletions

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++ DELETE queries
++ FROM clause
++ JOIN syntax
++ MAP keyword
++ WHERE clause
++ Conditional expressions
++ Functional Expressions

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Syntax:
<code>
[[LEFT | INNER] JOIN <component_reference1>] [ON | WITH] <join_condition>,
[[LEFT | INNER] JOIN <component_reference2>] [ON | WITH] <join_condition>,
[[LEFT | INNER] JOIN <component_reference1>] [ON | WITH] <join_condition1> [MAP] <map_condition1>,
[[LEFT | INNER] JOIN <component_reference2>] [ON | WITH] <join_condition2> [MAP] <map_condition2>,
...
[[LEFT | INNER] JOIN <component_referenceN>] [ON | WITH] <join_condition>
[[LEFT | INNER] JOIN <component_referenceN>] [ON | WITH] <join_conditionN> [MAP] <map_conditionN>
</code>
DQL supports two kinds of joins INNER JOINs and LEFT JOINs. For each joined component, you can optionally specify an alias.
@ -37,6 +37,7 @@ Would have a SQL equivalent:
SELECT u.id AS u__id, p.id AS p__id FROM User u LEFT JOIN Phonenumber p ON u.id = p.user_id
</code>
+++ ON keyword
If you want to override this behaviour and add your own custom join condition you can do it with the {{ON}} keyword. Consider the following DQL query:
<code>
@ -49,6 +50,7 @@ This query would be converted into SQL:
SELECT u.id AS u__id, p.id AS p__id FROM User u LEFT JOIN Phonenumber p ON u.id = 2
</code>
+++ WITH keyword
Most of the time you don't need to override the primary join condition, rather you may want to add some custom conditions. This can be achieved with the {{WITH}} keyword.
DQL:
@ -61,6 +63,7 @@ SQL:
SELECT u.id AS u__id, p.id AS p__id FROM User u LEFT JOIN Phonenumber p ON u.id = p.user_id AND u.id = 2
</code>
The Doctrine_Query API offers two convenience methods for adding JOINS. These are called innerJoin() and leftJoin(), which usage should be quite intuitive as shown below:
<code type="php">
@ -72,4 +75,3 @@ $q->from('User u')
$users = $q->execute();
</code>

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++ MAP keyword
The MAP keyword offers a way of mapping certain columns as collection / array keys. By default Doctrine maps multiple elements to numerically indexed arrays / collections. The mapping starts from zero. In order to override this behaviour you need to use MAP keyword as shown above:
<code type="php">
$q = new Doctrine_Query();
$q->from('User u MAP u.name');
$users = $q->execute();
</code>
Now the users in $users collection are accessible through their names.
<code type="php">
print $user['jack daniels']->id;
</code>
The MAP keyword can be applied to any given JOIN. This means that any given component can have each own mapping behaviour. In the following we use distinct mappings for both Users and Groups.
<code type="php">
$q = new Doctrine_Query();
$q->from('User u MAP u.name')->innerJoin('u.Group g MAP g.name');
$users = $q->execute();
</code>
Now lets print out the drinkers club's creation date.
<code>
print $users['jack daniels']->Group['drinkers club']->createdAt;
</code>