原则：使用子查询生成树路径

Question

I'm trying to generate a category path using a closure table. But I'm having a problem converting my query into DQL as doctrine doesn't support sub-queries, as far as I know. Is there a way to do it or any other workaround?

category table :-

id    name          slug

1     Category A    category-a
2     Category B    category-b
3     Category C    category-c

category_closure table :-

ancestor_id    descendant_id    path_length

4              4                0
4              44               1
4              53               2
44             44               0
44             53               1
53             53               0

Desired result :-

id    name         path

3     Category C   category-a/category-b/category-c

SQL executed :-

SELECT c.id, c.name, tmp.path
FROM category c
INNER JOIN (
    SELECT a.descendant_id, group_concat( c1.slug
    ORDER BY a.path_length DESC
    SEPARATOR '/' ) AS path
    FROM category c1
    JOIN category_closure a ON c1.id = a.ancestor_id
    WHERE a.descendant_id = 3
) tmp ON c.id = tmp.descendant_id

My doctrine associations are as follows:-

AppBundle\Entity\Category:
    type: entity
    table: category
    repositoryClass: AppBundle\Repository\CategoryRepository
    oneToMany:
        closure:
            targetEntity: CategoryClosure
            mappedBy: category

AppBundle\Entity\CategoryClosure:
    type: entity
    table: category_closure
    manyToOne:
        category:
            targetEntity: Category
            inversedBy: closure
            joinColumn:
                name: descendant_id
                referencedColumnName: id

1. Is my query optimized?
2. How to write this query using doctrine?

Any help is greatly appreciated. Thanks

Answer 1

You can use DoctrineExtensions -> tree to build closure and take advantage of repository methods. https://github.com/Atlantic18/DoctrineExtensions/blob/master/doc/tree.md#repository-methods . I encourage you also to take a look at the source.

Other sollution is to use doctrine native query. Another sollution is to operate on pure connection on entity manager object.