Laravel HasMany across multiple connections

I want to retrieve Offers related to Offer on a second table offer_related because I can’t change the schema of the Offer table.

I have two databases on different connections, offers on one, and offer_related on another.

For the sake of argument, I’m going to name databases as follows for clarity in my examples with regards to which can change and which can’t.

database containing offers henceforth known as immutable
database containing offer_related henceforth known as mutable

Example schema is as follows

connection1.mutable.offer_related

offer_id | related_offer_id
---------------------------
1        | 2
1        | 3

connection2.immutable.offers

id | name
---------------------------
1  | foo
2  | bar
3  | baz

I’m assuming it’d be a belongsToMany relationship, but I can’t seem to get it right.

return $this->belongsToMany(Offer::class, 'immutable.offer', 'id');

// Syntax error or access violation: 1066 Not unique table/alias: 'offer'

I’ve also tried to manually build out a belongsToMany relationship with a custom query with no success.

I’d like to be able to call

Offer::find(1)->related; // Offer(2), Offer(3)

Answer

Change the relationship to:

    return $this->belongsToMany(Offer::class, 'mutable.offer_related', 
                                'offer_id', 'related_offer_id');

Your original query was trying to establish a relationship without using the relation table (offer_related). That is the problem.

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Answer