[9.x] Make whereBelongsTo accept Collection

[erikgaal]

Hi there!

Extending upon #38927, I'm submitting this PR that allows you to retrieve records using a collection of related records.

Previously, if you wanted to retrieve, for example, all Posts that belong to one of multiple Categories, you would need to perform the following query:

$query->whereBelongsTo($category[0])
    ->orWhereBelongsTo($category[1])
    // etc...

// Or:
$query->whereIn('category_id', $categories->modelKeys());

Same as in the aforementioned PR, you would need to know the key names when building and maintain these if they change. This PR adds support for Collections passed to the whereBelongsTo method:

$query->whereBelongsTo($categories);

$query->whereBelongsTo($categories, 'category');

[a-bashtannik]

Could somebody explain or point to the docs, why whereIn accepts a flag boolean supposing 2 values: and and or while the SQL IN operator is a shorthand for multiple or conditions? Thanks!

[erikgaal]

@a-bashtannik It allows you to make the distinction between adding and "column" in ? and or "column" in ? to the SQL query. It's the same for all where methods in the Builder.

[a-bashtannik]

@erikgaal argghh so simple true, thanks!

[taylorotwell]

@erikgaal did you give any thoughts to just baking this functionality into whereBelongsTo?

[erikgaal]

@erikgaal did you give any thoughts to just baking this functionality into whereBelongsTo?

No, I haven't. Seems logical to support both a single Model and a Collection as arguments. If that works for you too, I'm happy to implement it that way!

[taylorotwell]

@erikgaal yeah I think it's fine to bake this behavior into the existing method.

[erikgaal]

@taylorotwell Done!