Php Laravel:1215无法添加外键约束-迁移时
我有一个表类别,它有自己类型的父类Php Laravel:1215无法添加外键约束-迁移时,php,mysql,laravel,migration,database-migration,Php,Mysql,Laravel,Migration,Database Migration,我有一个表类别,它有自己类型的父类 Schema::create('categories', function (Blueprint $table) { $table->bigIncrements('id'); $table->string('name'); $table->integer('parent_id')->unsigned()->nullable()->default(null); $
Schema::create('categories', function (Blueprint $table) {
$table->bigIncrements('id');
$table->string('name');
$table->integer('parent_id')->unsigned()->nullable()->default(null);
$table->foreign('parent_id')->references('id')->on('categories');
$table->timestamps();
});
抛出:
SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint (SQL: alter table `categories` add constraint `categories_parent_id_foreign` foreign key (`parent_id`) references `categories` (`id`))
我已经尝试在单独的Schema::table函数中将parent_id设置为外来,但没有成功。表是InnoDB类型。尝试将FK从整数更改为bigInteger:
$table->bigInteger('parent_id')->unsigned()->nullable()->default(null);
或
为什么要创建引用所创建表的FK?家长id应该参考家长表上的id,正如我在第一行中提到的,类别有类别H的家长,我的坏。我没看见。
$table->unsignedBigInteger('parent_id')->nullable()->default(null);