SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint in laravel 8

Question

hi i am trying to make category and then subcategory so if a category is deleted subcategory would also be deleted here what i have done so far created a model called category also created a subcategory model

run the migration for the category

 public function up()
    {
        Schema::create('categories', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->string('image');
            $table->string('slug');
            $table->timestamps();
        });
    }

in my subcategories migration i have defined the

public function up()
   {
       Schema::create('subcategories', function (Blueprint $table) {
           $table->increments('id');
           $table->unsignedBigInteger('category_id');
           $table->string('name');
           $table->string('slug');
           $table->timestamps();

           $table->foreign('category_id')->references('id')->on('categories')->onDelete('cascade');
       });
   }

when i try to migrate i am running in to error which states that Illuminate\Database\QueryException

SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint (SQL: alter table subcategories add constraint subcategories_category_id_foreign foreign key (category_id) references categories (id) on delete cascade)

my laravel version is 8.40 nd sqlversion is 5.7.24

did change the timestamp of both tables still it didn't work

2021_06_09_000000_create_categories_table.php 2021_06_10_055026_create_subcategories_table.php

even i tried


$table->foreignId('category_id')->constrained('categories');

score 0 · Answer 1 · edited Jun 10 '21 at 08:30

0

Just use

$table->foreignId('category_id)

Instead of

$table->unsignedBigInteger('category_id')
$table->foreign('category_id')->references('id')

edited Jun 10 '21 at 08:30

Peter Csala

17,736
16
35
75

answered Jun 10 '21 at 03:41

Sakeef Ameer Prodhan

1

Bibhudatta Sahoo · Answer 2 · 2021-06-10T06:42:55.240

0

For this you have to first create the table and then add the foreign key.
Like this

    Public function up()
   {
       Schema::create('subcategories', function (Blueprint $table) {
           $table->increments('id');
           $table->unsignedBigInteger('category_id');
           $table->string('name');
           $table->string('slug');
           $table->timestamps();
       });
   Schema::table('priorities', function($table) {
     $table->foreign('category_id')->references('id')->on('users')->onDelete('cascade');
   });
   }

For more details you can refer to this

edited Jun 10 '21 at 06:42

answered Jun 10 '21 at 03:59

Bibhudatta Sahoo

4,808
2
27
51

Schema::table('subcategories', function($table) { $table->foreign('category_id')->references('id')->on('categories')->onDelete('cascade'); }); – Zaeem Syed Jun 10 '21 at 05:52
did tried what u said error remains the same – Zaeem Syed Jun 10 '21 at 05:53
Check the reference once – Bibhudatta Sahoo Jun 10 '21 at 06:43

kliedo · Accepted Answer · 2021-06-10T06:32:43.510

0

Schema::create('categories', function (Blueprint $table) {
    $table->increments('id');
    $table->string('name');
    $table->string('image');
    $table->string('slug');
    $table->timestamps();
});

Schema::create('subcategories', function (Blueprint $table) {
    $table->increments('id');
    $table->unsignedInteger('category_id');
    $table->string('name');
    $table->string('slug');
    $table->timestamps();

    $table->foreign('category_id')->references('id')->on('categories')->onDelete('cascade');
        });

edited Jun 10 '21 at 06:32

answered Jun 10 '21 at 06:05

kliedo

26
5

Do you change $table->unsignedBigInteger('category_id'); to $table->unsignedInteger('category_id'); ? – kliedo Jun 10 '21 at 06:26
$table->unsignedInteger('category_id'); worked like a charm thank u so much :) – Zaeem Syed Jun 10 '21 at 06:30
Hope you can mark this answer as accepted :D – kliedo Jun 10 '21 at 06:37

SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint in laravel 8

3 Answers3