我有这四个表,但我在Laravel雄辩中得到了上述错误。任何人都可以告诉我在这里错过了什么?但是,当我删除外部方法迁移工作正常。获取错误:SQLSTATE [HY000]:一般错误:1215无法在Laravel 5中添加外键约束
Schema::create('students', function (Blueprint $table) {
$table->increments('id')->unsigned();
$table->string('first_name');
$table->string('last_name');
$table->string('middle_name');
$table->date('birthdate');
$table->integer('degree_id')->unsigned();
$table->index(['id','first_name', 'last_name']);
$table->timestamps();
$table->foreign('degree_id')
->references('id')
->on('degrees');
});
我包括无符号方法,但仍然得到上述错误。
Schema::create('degrees', function (Blueprint $table) {
$table->increments('id')->unsigned();
$table->string('description');
$table->string('category_id');
$table->integer('duration');
$table->string('sub_code');
$table->timestamps();
$table->foreign('sub_code')
->references('id')
->on('courses');
});
下面是另外两张表。
Schema::create('instructors', function (Blueprint $table) {
$table->increments('id')->unsigned();
$table->string('first_name');
$table->string('middle_name');
$table->string('last_name');
$table->date('birthdate');
$table->index(['id', 'first_name', 'last_name']);
$table->timestamps();
});
而最后的表:
Schema::create('courses', function (Blueprint $table) {
$table->string('id')->unique();
$table->string('description');
$table->integer('no_of_units');
$table->string('room_id');
$table->date('schedule');
$table->integer('instructor_id')->unsigned();
$table->timestamps();
$table->foreign('instructor_id')
->references('id')
->on('instructors');
});
也看看这里:http://stackoverflow.com/questions/22615926/migration-cannot-add-foreign-key-constraint-in-laravel –