添加外键到迁移（Laravel）

Question

我花了一整天的时间试图弄清楚下面的迁移发生了什么。

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迁移时，我遇到了以下错误：

SQLSTATE[HY000]：一般错误：1215无法添加外键约束（SQL:alter tablebooking\u stays\u abroadsadd constraintbooking\u stays\u abroads\u id\u stays\u Outside\u foreign外键（id\u stays\u Outside）引用

伙计们，先谢谢你们。




Answer 1

我也是Laravel的新手，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();

到

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

值得一试！

Answer 2

首先，属性应命名为“stays\u Outside\u id”，而不是“id\u stays\u Outside”。

问题是stays_abroads.id和stays_abroid_id的大小和性质应该匹配（在本例中为无符号大整数）。

此外，数据透视表中不需要ID。您不会在laravel中为其声明模型。

表的名称应反映数据透视表的两面，因此将其命名为stays\u Outside\u user（单数和字母顺序用下划线分隔）

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 3

对于id和id\u stays\u Outside，您没有使用相同的列定义。使用无符号BigInteger，而不是无符号整数。

php prettyprint-override">$table->unsignedBigInteger('id_stays_abroad')->nullable();
$table->unsignedBigInteger('user_id')->nullable();