Laravel migration self referencing foreign key issue

Question

Hi I have a problem to create a table using migration schema builder. The problem occure with table with self referencing foreign key. Here is the code which produce error:

        Schema::create('cb_category', function($table)
    {
        $table->integer('id')->primary()->unique()->unsigned();
        $table->integer('domain_id')->unsigned();
        $table->foreign('domain_id')->references('id')->on('cb_domain'); 
        $table->integer('parent_id')->nullable(); 
        $table->foreign('parent_id')->references('id')->on('cb_category')->onUpdate('cascade')->onDelete('cascade'); 
        $table->string('name');
        $table->integer('level');
    });

Here is the error:

  SQLSTATE[HY000]: General error: 1005 Can't create table 'eklik2.#sql-7d4_e' (errno: 150) (SQL: alter table `cb_cate

goryadd constraint cb_category_parent_id_foreign foreign key (parent_id) referencescb_category(id`) on del ete cascade on update cascade) (Bindings: array ( ))

[PDOException] SQLSTATE[HY000]: General error: 1005 Can't create table 'eklik2.#sql-7d4_e' (errno: 150)

Any idea?

Answer 1

You have to break this into two Schema blocks, one creating the columns, the other adding the FKs. mysql can't do both at the same time.

Answer 2

I may be too late for the party, but the official docs claim that the foreign key, in case of integer, must be ->unsigned();

http://laravel.com/docs/4.2/schema#foreign-keys

Note: When creating a foreign key that references an incrementing integer, remember to always make the foreign key column unsigned.

Also, Artisan does not fail if you (as I have) misspell unsigned() and I have spent quite a few hours trying to figure out why the key was not created.

So two things: 1. Always make the foreign key column unsigned in case of incrementing integers 2. Check the spelling of unsigned()

Answer 3

Schema::create('cb_category', function (Blueprint $table) {
        $table->increments('id')->unsigned();
        $table->integer('domain_id')->unsigned();
        $table->foreign('domain_id')->references('id')->on('cb_domain');
        $table->integer('parent_id')->nullable();
        $table->foreign('parent_id')->references('id')->on('cb_category')->onUpdate('cascade')->onDelete('cascade');
        $table->string('name');
        $table->integer('level');
    });

Try this

Answer 4

Two querys work :

Schema::create('cb_category', function($table)
{
    $table->integer('id')->primary()->unique()->unsigned();
    $table->integer('parent_id')->nullable();  
});

Schema::table('cb_category', function (Blueprint $table) 
{
    $table->foreign('parent_id')->references('id')->on('cb_category')->onUpdate('cascade')->onDelete('cascade');
});