Doctrine EAV orderBy and search

Question

I'm using Symfony 5 and Doctrine 2.10 My Book entity have no direct properties, all the fields are made via Entity-Attribute-Value pattern, like so:

Book:

#[ORM\OneToMany(mappedBy: 'book', targetEntity: BookAttributeValue::class)]
private Collection $bookAttributeValues;

BookAttributeValue:

#[ORM\ManyToOne(targetEntity: Book::class, inversedBy: 'bookAttributeValues')]
#[ORM\JoinColumn(nullable: false)]
private Book $book;

#[ORM\ManyToOne(targetEntity: Attribute::class)]
#[ORM\JoinColumn(nullable: false)]
private BookAttribute $bookAttribute;

#[ORM\Column(type: 'string')]
private string $value;

BookAttribute

#[ORM\Column(type: 'string', length: 50)]
private string $name;

#[ORM\Column(type: 'string', length: 50)]
private string $handle; // Like: NAME, DESCRIPTION, AUTHOR etc.

To select the books for listing I'm doing in BookRepositry:

$qb = $this->createQueryBuilder('book');

        $qb
            ->addSelect([
                'bookAttributeValues',
                'bookAttribute',
            ])
            ->leftJoin('book.attributeValues', 'bookAttributeValues')
            ->leftJoin('bookAttributeValues.bookAttribute', 'bookAttribute')
            ->andWhere(
                $qb->expr()->in('bookAttribute.handle', [
                    BookAttribute::NAME,
                    BookAttribute::DESCRIPTION,
                ]),
            );

Then I can access my attributes like so:

$book = $books[0];
foreach($book->attributeValues as $value) {
   echo $value->attribute->name . ' : ' . $value->value . '<br>';
}

The question is, how to, say, order by name on the state of SQL fetching? Or How to search by name? How the Doctrine QB would look like?

Answer 1

DQL Relational Limitations

Since EAV uses a schema-less design pattern, there is not a direct approach to accomplish the filtering or sorting with the ORM using DQL (QueryBuilder), as the resulting values ( Book::$attributeValues ) in the database are ambiguous:

[
     ['value' => 'name_value'], 
     ['value' => 'description_value']
]

Simply put, the ORM is not intended to be used for this type of "reporting".

DQL Workaround

One workaround to the relational issue mentioned above ( Book::$attributeValues ), is by mapping the query builder manually, in order to isolate the NAME attribute and associated values, that can then be used to be filtered ( = , IN() , LIKE ) or sorted.

Sort NAME Attribute Value

Use AS HIDDEN to add an arbitrary aliased join column, that can be used to be sorted.

$qb = $this->createQueryBuilder('book');
$expr = $qb->expr();

$qbS = $em->createQueryBuilder()
    ->select('na.id')
    ->from(BookAttribute::class, 'na')
    ->where($expr->eq('na.handle', ':attribute_name'));

$qb->addSelect([
        'bookAttributeValues',
        'bookAttribute',
        'nav.value AS HIDDEN name_value',
    ])
    ->leftJoin('book.attributeValues', 'bookAttributeValues')
    ->leftJoin('bookAttributeValues.bookAttribute', 'bookAttribute')

    //isolate the associated name attribute value as a separate column
    ->leftJoin(BookAttributeValue::class, 'nav', 'WITH', $expr->andX(
         $expr->eq('book.id', 'IDENTITY(nav.book)'),
         $expr->in('IDENTITY(nav.attribute)', $qbS->getQuery()->getDQL())
    ))
    ->andWhere($expr->in('bookAttribute.handle', ':attributes'))
    ->setParameter('attribute_name', BookAttribute::NAME)
    ->setParameter('attributes', [BookAttribute::NAME, BookAttribute::DESCRIPTION])
    ->addOrderBy('name_value')
    ->addOrderBy('a.name', 'ASC'); //Z-A (Name, Description)

Filter Results by NAME Attribute Value

Simply add the criteria to your statement.

$qb->andWhere($expr->eq('nav.value', ':attribute_value'))
    ->setParameter('attribute_name', '<desired_name_value>')

---

SQL Query Alternative

Due to the limitations, I suggest converting the DQL to an SQL query and use separate nested JOIN statements for the attributes and their associated values. Creating a pivot-table of the relationships. Then you can order by the aliased name join column value.

Name Attribute Related Values

SELECT nav.value AS name
#...
LEFT JOIN (book_attribute_value AS nav
INNER JOIN book_attribute AS na 
ON na.id = nav.attribute_id
AND na.handle = BookAttribute::NAME)
ON book.id = nav.book_id 

Description Attribute Related Values

SELECT dav.value AS description
#...
LEFT JOIN (book_attribute_value AS dav 
INNER JOIN book_attribute AS da
ON da.id = dav.attribute_id
AND da.handle = BookAttribute::DESCRIPTION)
ON book.id = dav.book_id 

Full Example DB-Fiddle

The nested join will cause a missing description or name attribute value for the associated book to return as NULL in that column as opposed to excluding the entire row.

class BookRepository
{

    /*
     * @return array|string[][]
     */
    public function filterBooks()
    {
        $sql = <<<SQL
SELECT 
    book.*,
    nav.value AS name,
    dav.value AS description
FROM book
LEFT JOIN (book_attribute_value AS nav
INNER JOIN book_attribute AS na 
ON na.id = nav.attribute_id
AND na.handle = :attr_name)
ON book.id = nav.book_id 
LEFT JOIN (book_attribute_value AS dav 
INNER JOIN book_attribute AS da
ON da.id = dav.attribute_id
AND da.handle = :attr_descr)
ON book.id = dav.book_id 
ORDER BY name
SQL;

        $stmt = $this->_em->getConnection()->prepare($sql);
        $stmt->bindValue('attr_name', BookAttribute::NAME);
        $stmt->bindValue('attr_descr', BookAttribute::DESCRIPTION);

        return $stmt->executeQuery()->fetchAllAssociative();
    }
}

Result

id	name	description
1	Book_1_Name	Book_1_Description
2	Book_2_Name	Book_2_Description

[
   {"id": "1", "name": "Book_1_Name", "description": "Book_1_Description"},
   {"id": "2", "name": "Book_2_Name", "description": "Book_2_Description"}
]

---

To iterate over the results as desired.

$books = $em->getRepository(Book::class)->filterBooks();
foreach ($books as $book) {
    //ksort($book, SORT_NATURAL); #optionally sort by the attribute column
    //printf('Book %s:<br>', $book['id']); #display the book id
    unset($book['id']); //remove the id column
    foreach ($book as $attribute => $value) {
        printf('%s: %s<br>', $attribute, $value);
    }
}

Output

name: Book_1_Name
description: Book_1_Description
name: Book_2_Name
description: Book_2_Description

To limit the results for a specified name value, change the LEFT JOIN nav to an INNER JOIN nav and add the desired criteria ( = , IN() , LIKE ) to the ON clause of the statement.

Example Query DB-Fiddle

SELECT 
    book.*,
    nav.value AS name,
    dav.value AS description
FROM book
INNER JOIN (book_attribute_value AS nav
INNER JOIN book_attribute AS na 
ON na.id = nav.attribute_id
AND na.handle = :attr_name)
ON book.id = nav.book_id 
AND nav.value = :name_value
LEFT JOIN (book_attribute_value AS dav 
INNER JOIN book_attribute AS da
ON da.id = dav.attribute_id
AND da.handle = :attr_descr)
ON book.id = dav.book_id 

Be sure to bind the value to the statement criteria.

$stmt->bindValue('name_value', 'Book_1_Name');