Oihana PHP Arango

resolveFacetJoin.php

Table of Contents

Functions

resolveFacetJoin()  : array{0: string, 1: string, 2: string}
Resolves the **anchor** of a key-join facet: the `FOR` opening the joined collection and the predicate tying a joined document to the main one.

Functions

resolveFacetJoin()

Resolves the **anchor** of a key-join facet: the `FOR` opening the joined collection and the predicate tying a joined document to the main one.

resolveFacetJoin(string $key, array<string|int, mixed> $facet, string $doc) : array{0: string, 1: string, 2: string}

The three join facets — HasFacetJoin, HasFacetJoinAggregate and HasFacetJoinComplex — differ in what they do with the joined documents (test their existence, aggregate a numeric field over them, match several of their fields), never in how they reach them. That reaching is this helper: it reads the join definition and returns the three fragments every one of them needs.

The join is doc_<key>.<AQL::KEY> == doc.<Facet::PROPERTY>, with AQL::KEY the joined side (default _key) and Facet::PROPERTY the main side (default the facet key) — which expresses both "the document holds the foreign key" and the reverse one-to-many "the joined documents reference the document". When AQL::ARRAY is set the main side holds an array of keys, so the equality becomes a membership test (IN).

Parameters
$key : string

The facet key; drives the joined document reference (doc_<key>) and the default main-side property.

$facet : array<string|int, mixed>

The facet definition (AQL::COLLECTION, AQL::KEY, Facet::PROPERTY, AQL::ARRAY).

$doc : string

The main document reference.

Tags
throws
ReflectionException
example 
use function oihana\arango\models\helpers\facets\resolveFacetJoin;

// Posts joined to their author: doc.authorId == author._key
[ $docRef , $for , $match ] = resolveFacetJoin( 'author' , [ AQL::COLLECTION => 'authors' , Facet::PROPERTY => 'authorId' ] , 'doc' ) ;
// $docRef = 'doc_author'
// $for    = 'FOR doc_author IN authors'
// $match  = 'doc_author._key == doc.authorId'

// The main document holds an array of keys
[ , , $match ] = resolveFacetJoin( 'tags' , [ AQL::COLLECTION => 'tags' , AQL::ARRAY => true , Facet::PROPERTY => 'tagIds' ] , 'doc' ) ;
// $match = 'doc_tags._key IN doc.tagIds'
since
1.6.0
author

Marc Alcaraz

Return values
array{0: string, 1: string, 2: string} —

A [ docRef , for , match ] triplet: the joined document reference, the FOR doc_<key> IN <collection> clause, and the join predicate to place in the FILTER.

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