mysql - Laravel 抛出一般错误 : 1215 Cannot add foreign key constraint"when I create foreign keys

Question

我正在使用 Laravel 6。我创建了一些迁移，但我无法让它们成功运行。这些是我的迁移。

    public function up()
{
    Schema::create('nationalities', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->string('name');
        $table->timestamps();
        $table->engine = "InnoDB";
    });


    public function up()
{
    Schema::create('genders', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->string('name');
        $table->timestamps();
        $table->engine = "InnoDB";
    });


    public function up()
{
    Schema::create('users', function (Blueprint $table) {
        $table->bigIncrements('id');
        $table->string('firstname');
        $table->string('lastname');
        $table->string('street');
        $table->string('zip');
        $table->string('city');
        $table->date('birthdate');
        $table->string('gender');
        $table->string('email')->unique();
        $table->timestamp('email_verified_at')->nullable();
        $table->string('password');
        $table->rememberToken();
        $table->timestamps();
        $table->unsignedBigInteger('gender_id');
        $table->unsignedBigInteger('nationality_id');
        $table->engine = "InnoDB";
        $table->foreign('gender_id')->references('id')->on('gender');
        $table->foreign('nationality_id')->references('id')->on('nationality');
    });
}

执行php artisan migrate后，我收到此错误消息:

General error: 1215 Cannot add foreign key constraint (SQL: alter table users add constraint users_gender_id_foreign foreign key (gender_id) references gender (id))

我做错了什么？

Answer 1

您的表格名称是genders而不是gender，并且nationalities不是nationality:

更改:

...->references('id')->on('gender');
...->references('id')->on('nationality');

致:

...->references('id')->on('genders');
...->references('id')->on('nationalities');