Clarify how to setup a one-to-many relationship in Laravel's Eloquent ORM
Please refer to the laravel docs on the one to many relationship between posts and comments http://laravel.com/docs/eloquent#relationships. (Where one post has many comments and a comment belongs to a post).
The tables for posts and comments be as follows
Posts Table id | title | body
Comments Table id | comment | post_id
The database table that contains a foreign key belongs to a record in the other table, therefore, in the comments model you must specify that comments belongs to posts.
You are correct that the hasOne relationship only applies to one to one relationships.
Here is a blog post with laravel 3 code which gives an explanation into how eloquent relationship methods work.
http://laravel.io/topic/14/how-eloquent-relationship-methods-work
Comments
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eimajenthat almost 2 years
Okay, I'm working through the Laravel 4 docs to setup a one-to-many relationship between two models. Obviously, one side should use hasMany(). But for the other side, should I use hasOne or belongsTo? Does it matter? What's difference? Why do both exist?
I had thought hasOne would be for one-to-one relationships, and belongsTo would be for the one side of one-to-many. But in the docs, for inserting a related model here:
http://laravel.com/docs/eloquent#inserting-related-models
they are using
save()
which seems to only be present inhasOne
andhasMany
relationships, not inbelongsTo
. It looks likebelongsTo
usesassociate()
for the same purpose:Maybe I just need some general background on when to use
belongsTo
vs.hasOne
, and whybelongsTo
usesassociate()
whilehasOne
usessave()
.EDIT: I guess my point of confusion was that in the docs (http://laravel.com/docs/eloquent#inserting-related-models), they used:
$post->comments()->save($comment);
where I would have used:
$comment->post()->associate($post);
Is there an advantage to one way or the other? Or is it just a question of what makes sense in the context?
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Brent Connor over 8 yearsThis helped because I had my relationships defined backwards. I had the table with the foreign key as the
hasMany
.