Laravel-在外键中设置默认值

Question

我使用SET DEFAULT来限制外键：

public function up()
    {
        Schema::create('phong', function (Blueprint $table) {
            $table->engine='InnoDB';
            $table->bigIncrements('p_id');
            $table->string('p_ma',50);
            $table->string('p_ten',50);
            $table->unsignedTinyInteger('p_soNguoi')->default('0');
            $table->text('p_ghiChu',200)->nullable();
            $table->unique(['p_ma','p_ten']);
            $table->timestamp('p_taoMoi')->default(DB::raw('CURRENT_TIMESTAMP'));
            $table->timestamp('p_capNhat')->default(DB::raw('CURRENT_TIMESTAMP'));
            $table->unsignedTinyInteger('p_trangThai')->default('2');
            $table->unsignedTinyInteger('lp_ma');
            $table->unsignedTinyInteger('k_ma');
            $table->foreign('lp_ma')->references('lp_ma')->on('loaiphong')->onDelete('SET DEFAULT')->onUpdate('SET DEFAULT');
            $table->foreign('k_ma')->references('k_ma')->on('khu')->onDelete('SET DEFAULT')->onUpdate('SET DEFAULT');
        });
    }

但是这不起作用，这个错误是：外键约束在   正确形成。  当我想从表'khu'或'loaiphong'中删除一行时，表的这些数据不会被删除。任何的想法？感谢

Answer 1

外键约束

  

Laravel还支持创建外键约束，这些约束用于强制数据库级别的引用完整性。例如，让我们在posts表上定义一个user_id列，该列引用users表上的id列：

Schema::table('posts', function (Blueprint $table) {
$table->integer('user_id')->unsigned();

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

  

您还可以为约束的“on delete”和“on update”属性指定所需的操作：

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

Drop Column

public function down()
{
    Schema::table('phong', function (Blueprint $table) {
        $table->dropForeign('khu');
    });
}

Read the full docs