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Laravel forbid updating row if its referenced in another table

say Table A and Table B (table B has a foreign key a_id)
I want to be able to update a row in A as long as it’s not ref in B
I already did it but I’m looking for a better approach.

My approach

$referencesInB = TableB::where('a_id', $id)->exists();
if ($referencesInB) {
    return response()->json(['error' => 'Cannot update'], 403);
}
$rowA->update($request->all());
Tags:

2

Answers


  1. 0

    You can do it upstream where you first get $rowA

    $rowA = TableA::whereDoesntHave('B')->findOrFail($id);

//or

$rowA = AClass::whereDoesntHave('B')->find($id);
if (!$rowA) {
    return response()->json(['error' => 'Cannot update'], 403);
}

    'B' is the name of the relation difined in TableA model class

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  2. 0 
    $referencesInB = TableB::where('a_id', $id)->exists();

    You can avoid the extra query check above(saving us a few milliseconds or more) by eager loading the relation and checking if the relation actually loaded. So, it all happens with 1 query instead of 2 eliminating the N + 1 query issue
    docs.

    <?php

$rowA = TableA::with('table_b')->find($id);

if ($rowA->relationLoaded('table_b')) {
  return response()->json(['error' => 'Cannot update'], 403);
}

$rowA->update($request->all());
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