Level 9
I think you can also eager load the routine relation when loading the progress
something along the lines of
Records::with("progress.routine")
2 likes
Apr 18, 2017
6
Level 12
How to use parent and child relation as constrain on grandchild?
Forgive me if the title is not clearly stated. I have this particular problem (perhaps due to the initial design of the database relation). Is it possible to use the columns in parent together with the columns in child ( via eager load with([]) ) as a constrain to the grand-child?
I have 3 tables. Let's call them
- Records
- Progress
- Routine
The relation between them are as follows:
- Records (hasMany)-> Progress
- Progress (belongsTo)-> Records
- Progress (hasMany)-> Routine
There is no direct relation between Records and Routine. It can be said that Routine are just logs.
In order to retrieve Routine for specific Records. Routine must use two parent relation, 1 column (Routine.Serial) matches with Progress another column (Routine.Date) matches with Records.
I was able to eager load (or Lazy Load) Records and Progress. However I couldn't do so to eager load Routine below Progress with additional constrain from Records
How can I use the "Date" in Records and "Serial" in Progress as constrain to retrieve Routine via eager loading.
If it's impossible, then I'll have to run into the N+1 query problem as I have to lookup for each Progress in order to retrieve the Routine.
p/s: Is there any 'preview' function before I open discussion?
Level 12
Well, I could load the Routine via eager load the Progress, however it'll return ALL the data (it's a lot), so I need additional constraint (or filters) by "Date" from Records
Level 9
Well.. I think you can add constraits on your eager loads, something along the lines of
$users = App\Record::where()->with(['progress' => function ($query) {
//add the constraits her
$query->where('');
}])->get();
1 like
Level 12
I have tried this, I could only add constrain from the child to grand-child, but not constrain from parent to grand-child.
Level 24
First of all, I am sorry if I mistakenly understand your question.
Did you know you can use hasManyThrough?
on your Record class
public function routines()
{
return $this->hasManyThrough('App\Routine', 'App\Progress');
}
and you can do something like
App\Record::with(['routines' => function($q) {
//your constraint here
$q->
}]);
further reading https://laravel.com/docs/5.4/eloquent-relationships#has-many-through
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Level 12
I haven't looked into hasManyThrough.
Thanks for the heads up. By the look at it in the documentation. It allows Records to have relationship with Routine through the intermediate Progress
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