Oihana PHP Arango

expandArrayPath.php

Table of Contents

Functions

expandArrayPath()  : array{0: string[], 1: string}
Unwinds an array-expansion path into the chain of `FOR` hops AQL needs to walk it, plus the reference of the projected leaf.

Functions

expandArrayPath()

Unwinds an array-expansion path into the chain of `FOR` hops AQL needs to walk it, plus the reference of the projected leaf.

expandArrayPath(string $property, string $docRef[, string $itemRef = 'item' ]) : array{0: string[], 1: string}

It is the query-side counterpart of stripArrayExpansion(): where the search links and the hierarchical ?filter= builder flatten the Operator::ARRAY_EXPANSION marker into a dotted path, an aggregation has to unwind it — an array element cannot be aggregated in place, it must be iterated. 'offers[*].tiers[*].amount' becomes:

FOR item  IN doc.offers
FOR item2 IN item.tiers
  … item2.amount

The path is split on the marker, every segment but the last opening one hop relative to the previous item reference, and the last segment being the projected leaf — empty for a bare tags[*], which projects the element itself. Each item reference is <itemRef>, then <itemRef>2, <itemRef>3 … (there is no <itemRef>1).

Every segment is validated by assertAttributeName() — the whole path never is, since it carries the markers — so a malformed path fails loud instead of reaching AQL. A doubled marker (a[*][*]) yields an empty intermediate container and is rejected on that ground.

The helper deliberately stops at the hops: the root FOR, the shared FILTER and the aggregation tail belong to the caller, and diverge between consumers (BoundsQueryTrait collects MIN/MAX/count, FacetCountsQueryTrait counts buckets).

Parameters
$property : string

The [*]-bearing attribute path.

$docRef : string

The document reference the first hop starts from.

$itemRef : string = 'item'

The base name of the item variables (default item).

Tags
throws
ReflectionException
ValidationException

When a container or the leaf is not a valid attribute name.

example 
use function oihana\arango\db\helpers\expandArrayPath;

expandArrayPath( 'offers[*].price' , 'doc' ) ;
// [ [ 'FOR item IN doc.offers' ] , 'item.price' ]

expandArrayPath( 'a[*].b.c[*].d' , 'doc' ) ;
// [ [ 'FOR item IN doc.a' , 'FOR item2 IN item.b.c' ] , 'item2.d' ]

expandArrayPath( 'tags[*]' , 'doc' ) ;
// [ [ 'FOR item IN doc.tags' ] , 'item' ]
since
1.6.0
author

Marc Alcaraz

Return values
array{0: string[], 1: string} —

A [ fors , value ] pair: the FOR hops in order, and the reference to project (the leaf, or the innermost item when the path ends on a marker).

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