[DC-627] Work on link-table and leftJoin

Tue, 13 Apr 2010 05:07:32 +0000

Looking at the attachment to see the little schema.
Tree table : items, items_children and children.

The link-table items_children is here to create a many-to-many relationships between Items and Children.

So, after configure the YAML and generated Models.
We can do something like that :

$query = Doctrine_Query::create ()
->select ("items.title, children.title")
->from ("Item items")
->leftJoin ("item.children children");
$items = $query->execute ();

$items //An array of items
$items[0]->title //A string
$items[0]->children //An array of children

The SQL Output of the query is :

SELECT `i`.`id_item` AS `i_id_item`, `i`.`title` AS `ititle`, `c`.`id_child` AS `cid_child`, `c`.`title` AS `c_title` FROM `items` `i` LEFT JOIN `items_children` `i2` ON (`i`.`id_item` = `i2`.`id_item`) LEFT JOIN `children` `c` ON `i2`.`id_child` = `c`.`id_child`

All array are order by something, in this case it's a natural order which come from the items_children order into database.

Now, I want to apply a condition, or a filter on the items_children table.
If I translate my demand to SQL Query :

SELECT `i`.`id_item` AS `i_id_item`, `i`.`title` AS `ititle`, `c`.`id_child` AS `cid_child`, `c`.`title` AS `c_title` FROM `items` `i` LEFT JOIN `items_children` `i2` ON (`i`.`id_item` = `i2`.`id_item`) LEFT JOIN `children` `c` ON `i2`.`id_child` = `c`.`id_child` ORDER BY `c1`.`index`

Or something crazy :

SELECT `i`.`id_item` AS `i_id_item`, `i`.`title` AS `ititle`, `c`.`id_child` AS `cid_child`, `c`.`title` AS `c_title` FROM `items` `i` LEFT JOIN `items_children` `i2` ON (`i`.`id_item` = `i2`.`id_item`) LEFT JOIN `children` `c` ON `i2`.`id_child` = `c`.`id_child` WHERE `c1`.`index` > 2

But how can I do that with DQL ? Because I have no access to the Link-table.

Link-Table are use to create many-to-many, that could be OOP array. So we have to be allowed to add "index" to order the result. Also, we have to be allowed to add condition on this tables, like "datePromote" or simply "enabled".

The solution should be on the following DQL Query :

$query = Doctrine_Query::create ()
->select ("items.title, children.title")
->from ("Item items")
->leftJoin ("item.children children")
->leftJoin ("ItemsChildren link_table")
->orderBy ("link_table.index")
$items = $query->execute ();

But the SQL Output is :

SELECT `i`.`id_item` AS `i_id_item`, `i`.`title` AS `ititle`, `c`.`id_child` AS `cid_child`, `c`.`title` AS `c_title` FROM `items` `i` LEFT JOIN `items_children` `i2` ON (`i`.`id_item` = `i2`.`id_item`) LEFT JOIN `children` `c` ON `i2`.`id_child` = `c`.`id_child`, `items_children` `i3` ORDER BY `i3`.`index`

To conclude, it's a blocker problem. Because I can't use a standard DB schema.

Regards,
Armetiz.

Doctrine Project

[DC-627] Work on link-table and leftJoin