SQLSTATE [HY000]:一般错误:1005 无法创建表 - Laravel 4

I get this error when I do php artisan migrate. Is there something wrong in my migration files? Or is it possible my models are wrong coded? But the migrations should work even there is something wrong in the models?

[Exception]                                                                  
  SQLSTATE[HY000]: General error: 1005 Can't create table 'festival_aid.#sql-  
  16643_2033' (errno: 150) (SQL: alter table `gigs` add constraint gigs_band_  
  id_foreign foreign key (`band_id`) references `bands` (`band_id`) on delete  
   cascade) (Bindings: array (                                                 
  ))

[PDOException]                                                               
  SQLSTATE[HY000]: General error: 1005 Can't create table 'festival_aid.#sql-  
  16643_2033' (errno: 150)

演出迁移

public function up()
    {
        Schema::create('gigs', function($table)
        {
            $table->increments('gig_id');

            $table->dateTime('gig_startdate');

            $table->integer('band_id')->unsigned();
            $table->integer('stage_id')->unsigned();

            $table->foreign('band_id')
                ->references('band_id')->on('bands')
                ->onDelete('cascade');

            $table->foreign('stage_id')
                ->references('stage_id')->on('stages')
                ->onDelete('cascade');
        });

    public function down()
    {
        Schema::table('gigs', function($table)
        {
            Schema::drop('gigs');
            $table->dropForeign('gigs_band_id_foreign');
            $table->dropForeign('gigs_stage_id_foreign');
        });
    }

乐队迁移

public function up()
    {
        Schema::create('bands', function($table)
        {
            $table->increments('band_id');

            $table->string('band_name');
            $table->text('band_members');
            $table->string('band_genre');
            $table->dateTime('band_startdate');
        });
    }

    public function down()
    {
        Schema::table('bands', function(Blueprint $table)
        {
            Schema::drop('bands');
        });
    }

模型乐队

<?php

class Band extends Eloquent {

    protected $primaryKey = 'band_id';

    public function gig()
    {
        return $this->hasOne('Gig', 'band_id', 'band_id');
    }
}

模型演出

<?php

class Gig extends Eloquent {
    protected $primaryKey = 'gig_id';

    public function gig()
    {
        return $this->belongsTo('Band', 'band_id', 'band_id');
    }

    public function stage()
    {
        return $this->belongsTo('Stage', 'stage_id', 'stage_id');
    }
}

推荐答案

必须先创建表，再创建外键:

Schema::create('gigs', function($table)
{
    $table->increments('gig_id');

    $table->dateTime('gig_startdate');

    $table->integer('band_id')->unsigned();
    $table->integer('stage_id')->unsigned();
});

Schema::table('gigs', function($table)
{
    $table->foreign('band_id')
        ->references('band_id')->on('bands')
        ->onDelete('cascade');

    $table->foreign('stage_id')
        ->references('stage_id')->on('stages')
        ->onDelete('cascade');
});