Level 6
Can u please provide your DB structure?
Jun 4, 2020
7
Level 3
How to model a hasMany relationship with an extra condition ?
I have a Category model with parent, children relations
The problem is my Category table holds multiple hierarchies from different websites and due to the nature of the project, I don't have a parent_id to uniquely point to a category, so I rely on this structure that adds an extra condition to the relations (parent.website = children.website):
Website Category Parent
A 1 null
A 2 1
Can I do this for relationships:
public function children() {
return $this->hasMany(Category)->where('website', $this->website);
}
And how do I create the migration to reflect it in terms of indexes ?
Level 3
Schema::create('categories', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('website', 100);
$table->string('hierarchy');
$table->string('parent_hierarchy')->nullable();
$table->timestamps();
});
Where hierarchy is the full category: Books>Crime>Short Novel And Parent hierarchy: Books>Crime. This is Website A
For Website B, I may have: Monitors>Led>4K
So I need to create a hasMany relation. And the added difficulty is the extra condition that the parent and child share the same website.
Level 6
So let me check if I understood u right. U are trying to write a relationship for children that will generate the following query:
SELECT * FROM category WHERE website = 'website_parent';
Level 3
SELECT * FROM
category categories
LEFT JOIN
category children
ON
categories.hierarchy=children.parent_hierarchy
AND
categories.website=children.website
Level 6
I believe that is currently not available in Laravel. However, this library that might help u.
https://github.com/topclaudy/compoships
I answered this very same questions two days ago. Check out this thread: https://laracasts.com/discuss/channels/laravel/two-way-pivot-table
Level 3
Thank you, I'll look into it, but not optimal for me, so I'll do it using plain SQL queries. I thought there may be a Eloquent way to achieve it.
Level 3
But seem you are right on this one. On that plugin it explicitly says:
Eloquent doesn't support composite keys. As a consequence, there is no way to define a relationship from one model to another by matching more than one column.
And gives exactly what I need as example.
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