Foreign keys in Laravel 4 migrations issue

Question

I've just created a new Laravel 4 project and am finding strange things happening with the foreign key aspect of the schema builder. If I use the ->foreign() method in any of my migrations I get thrown MySQL errors 150 and general error 1005. According to the documentation at laravel.com/docs the two scenario's at the bottom should work? Anyone know why they don't?

The following does work:

    Schema::create('areas', function($table)
    {
        $table->engine ='InnoDB';
        $table->increments('id');

        $table->integer('region_id')->references('id')->on('regions');

        $table->string('name', 160);
        $table->timestamps();
    });

But these two do not work:

    Schema::create('areas', function($table)
    {
        $table->engine ='InnoDB';
        $table->increments('id');

        $table->foreign('region_id')->references('id')->on('regions');

        $table->string('name', 160);
        $table->timestamps();
    });

    Schema::create('areas', function($table)
    {
        $table->engine ='InnoDB';
        $table->increments('id');

        $table->integer('region_id');
        $table->foreign('region_id')->references('id')->on('regions');

        $table->string('name', 160);
        $table->timestamps();
    });

Answer 1

Check your id type. Laravel 4 creates an incremental id with a int(10) unsigned. If you create a basic integer and try to put a foreign key on it, it will fail.

As suggested in the documentation at this link, you should create the foreign id with $table->unsignedInteger(YOUR_ID_NAME); to make it work.

Answer 2

Also some answers over at this question "General error: 1005 Can't create table" Using Laravel Schema Build and Foreign Keys

A Summary of the answers listed there, including mine:

1. Foreign Keys generally require InnoDb, so set your default engine, or explicitly specify $table->engine = 'InnoDB'; If your table is already created and has defaulted to MyISAM, you may need to alter it.
   

2. Foreign keys require the referenced table to exist. Make sure the referenced table is created in an earlier migration, prior to creating the key. Consider creating the keys in a separate migration to be sure.

3. Foreign Keys require the data type to be congruent. Check whether the referenced field is the same type, whether its signed or unsigned, whether it's length is the same (or less).

4. If you are switching between hand coding migrations, and using generators, make sure you check the id type you are using. Artisan uses increments() by default but Jeffrey Way appears to prefer integer('id', true).