将外键添加到迁移（Laravel）

Question

我花了一整天的时间试图弄清楚以下迁移发生了什么。

这是表的迁移。 我的想法是使用 'id_stays_abroad' 和 'user_id' 作为外键。

    class CreateBookingStaysAbroad extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('booking__stays__abroads', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->timestamps();
            $table->unsignedInteger('id_stays_abroad')->nullable();
            $table->unsignedInteger('user_id')->nullable();
            $table->string('status')->nullable();
            $table->date('departure_date');
            $table->date('return_date');
            $table->integer('number_weeks');

        });

    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('booking__stays__abroad');
    }
}

这是添加外键的另一个迁移

   class AddForeignKeyBookingStaysAbroadTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::table('booking__stays__abroads', function($table) {

            $table->foreign('id_stays_abroad')
                    ->references('id')
                    ->on('stays_abroads');

            $table->foreign('user_id')
                    ->references('id')
                    ->on('users');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
            Schema::table('booking__stays__abroads', function (Blueprint $table) {
            $table->dropForeign('booking__stays__abroads_id_stays_abroad_foreign');
            $table->dropForeign('booking__stays__abroads_user_id_foreign');

    });
  }
}

当我运行 php artisan migrate 时，出现以下错误：

SQLSTATE[HY000]：一般错误：1215 无法添加外键约束（SQL：alter table booking__stays__abroads添加约束booking__stays__abroads_id_stays_abroad_foreign外键（ id_stays_abroad ）引用stays_abroads （ id ））

提前谢谢各位。

Answer 1

试试这个，我认为你在用户表中的 id 是 bigIncrements.so for foreignkey 使用这个

$table->unsignedBigInteger('id_stays_abroad')->nullable();
$table->unsignedBigInteger('user_id')->nullable();

DB::statement('SET FOREIGN_KEY_CHECKS=0;');
Schema::table('booking__stays__abroads', function($table) {

            $table->foreign('id_stays_abroad')
                    ->references('id')
                    ->on('stays_abroads');

            $table->foreign('user_id')
                    ->references('id')
                    ->on('users');
        });
DB::statement('SET FOREIGN_KEY_CHECKS=1;');

DB::statement('SET FOREIGN_KEY_CHECKS=0;');
Schema::table('booking__stays__abroads', function (Blueprint $table) {
            $table->dropForeign('booking__stays__abroads_id_stays_abroad_foreign');
            $table->dropForeign('booking__stays__abroads_user_id_foreign');

DB::statement('SET FOREIGN_KEY_CHECKS=1;');

Answer 2

class CreateStaysAbroadTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('stays_abroads', function (Blueprint $table) {
            $table->bigIncrements('id');
            $table->timestamps();
            $table->string('location');
            $table->string('county');
            $table->string('nation');
            $table->string('country');
            $table->string('school');
            $table->string('accommodation');
            $table->text('landmarks');
            $table->integer('price_week');
            $table->engine = "InnoDB";
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('stays_abroad');
    }
}

这就是“stays_abroad”迁移。

 class CreateUsersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->bigIncrements('id')->unsigned();
            $table->string('name');
            $table->string('email')->unique();
            $table->timestamp('email_verified_at')->nullable();
            $table->string('password');
            $table->string('type');
            $table->rememberToken();
            $table->timestamps();
            $table->engine = "InnoDB";
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('users');
    }
}

这是默认用户迁移

Answer 3

您没有为id和id_stays_abroad使用相同的列定义。 使用unsignedBigInteger而不是unsignedInteger 。

$table->unsignedBigInteger('id_stays_abroad')->nullable();
$table->unsignedBigInteger('user_id')->nullable();

Answer 4

首先，属性应该命名为stays_abroad_id而不是id_stays_abroad 。

问题是stays_abroads.id和stays_abroid_id的大小和性质应该匹配（在这种情况下为无符号大integer）。

此外，您不需要 pivot 表中的 ID。 您不会在 laravel 中为其声明 model。

表名要体现pivot表的两侧，所以命名为stays_abroad_user （单数和字母顺序用下划线隔开）

class CreateBookingStaysAbroad extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('stays_abroad_user', function (Blueprint $table) {
            $table->unsignedBigInteger('stays_abroad_id')->nullable();
            $table->unsignedBigInteger('user_id')->nullable();
            $table->string('status')->nullable();
            $table->date('departure_date');
            $table->date('return_date');
            $table->integer('number_weeks');
            $table->timestamps();
            $table->foreign('stays_abroad_id')
                    ->references('id')
                    ->on('stays_abroads');

            $table->foreign('user_id')
                    ->references('id')
                    ->on('users');
        });

    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::dropIfExists('stays_abroad_user');
    }
}

Answer 5

我对 Laravel 也很陌生，但我认为您可能需要更改这两种数据类型：

$table->unsignedInteger('id_stays_abroad')->nullable();
$table->unsignedInteger('user_id')->nullable();

至

$table->unsignedBigInteger('id_stays_abroad')->nullable();
$table->unsignedBigInteger('user_id')->nullable();

值得一试！