SQLSTATE[HY000]: General error: 1005 Can't create table `test`.`members` (errno: 150 “Foreign key constraint is incorrectly formed”)

Question

I'm using my migrations in Laravel to create the relationships between tables, and I have 4 tables: users, members, member_skills, and skills. I have the following code for the users table:

public function up()
{
    Schema::create('users', function (Blueprint $table) {
        $table->id();
        $table->string('name');
        $table->string('email')->unique();
        $table->timestamp('email_verified_at')->nullable();
        $table->string('password');
        $table->rememberToken();
        $table->timestamps();
        $table->boolean('admin');
    });
}

the members table:

public function up()
{
    Schema::create('members', function (Blueprint $table) {
        $table->id();
        $table->timestamps();
        $table->string('name');
        $table->string('status');
        $table->date('date')->nullable();
        $table->text('project')->nullable();
        $table->date('start')->nullable();
        $table->foreign('name')->references('name')->on('users');
    });
}

the member_skills table:

public function up()
{
    Schema::create('member_skills', function (Blueprint $table) {
        $table->id();
        $table->timestamps();
        $table->string('name');
        $table->string('skill');
        $table->foreign('name')->references('name')->on('members');
    });
}

and the skills table:

public function up()
{
    Schema::create('skills', function (Blueprint $table) {
        $table->id();
        $table->timestamps();
        $table->string('skill');
        $table->text('description');
        $table->foreign('skill')->references('skill')->on('member_skills');
    });
}

However, running my migrations results to (errno: 150 "Foreign key constraint is incorrectly formed") . I have read that changing the migration order should fix the problem, so I have arranged the 4 tables to be migrated in the order of users, members, member_skills, and skills, but I am still receiving the same error. Is there anything else I'm doing wrong?

Answer 1

Here is the right way todo this

public function up()
{
   Schema::create('members', function (Blueprint $table) {
      ...
      $table->unsignedBigInteger('user_id');
      $table->foreign('user_id')->references('id')->on('users');
   });
}

public function up()
{
   Schema::create('member_skills', function (Blueprint $table) {
      ...
      $table->unsignedBigInteger('member_id');
      $table->foreign('member_id')->references('id')->on('members');
   });
}

public function up()
{
   Schema::create('skills', function (Blueprint $table) {
      ...
      $table->unsignedBigInteger('member_skill_id');
      $table->foreign('member_skill_id')->references('id')->on('member_skills');
   });
}

more:https://laravel.com/docs/8.x/migrations#foreign-key-constraints

Answer 2

You should try using the id of the member table as the foreign key rather than the name in the member_skills schema

    public function up()
    {
        Schema::create('member_skills', function (Blueprint $table) {
            $table->id();
            $table->timestamps();
            $table->string('member_id');
            $table->string('skill');
            $table->foreign('member_id')->references('id')->on('members');
        });
    }

You are getting this error because you are trying to reference name in the member table which is already a foreign key to the users table.

You can access the name of the member through the id foreign key in your blade.