Cannot add foreign key constraint in Laravel Migration

Question

I've found dozens of similar issues posted, but none of the solutions have seemed to work in my case. When I run "php artisan migrate:fresh", it's throwing the error...

Illuminate\Database\QueryException: SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint (SQL: alter table slicer_profiles add constraint slicer_profiles_user_id_foreign foreign key ( user_id ) references users ( id ) on delete cascade)

• All tables created are InnoDB
• The 'users' table is being created before my table

• I've split the code in to two steps, assigning the foreign key afterwards

  Schema::create('slicer_profiles', function (Blueprint $table) { $table->increments('id'); $table->integer('user_id')->unsigned()->index(); $table->string('title'); $table->text('description'); $table->string('slicer'); $table->string('machine'); $table->softDeletes(); $table->timestamps(); }); Schema::table('slicer_profiles', function($table) { $table->foreign('user_id')->unsigned() ->references('id') ->on('users') ->onDelete('cascade'); });

I check the auth users table and it seems to use an UNSIGNED BIGINT, so I try setting ->unsigned() on the reference as well, but no change. Any help solving this would be greatly appreciated!

Answer 1

If the users.id field is a BIGINT then your need to make the users_id column on slicer_profiles a BIGINT so that the 2 fields have exact matching types.

Schema::create('slicer_profiles', function (Blueprint $table) {
    ...
    $table->bigInteger('user_id')->unsigned()->index();
    // or $table->unsignedBigInteger('user_id')->index();
    ...
});