如何使用字符串格式在兩個(gè)表之間建立關(guān)系？我收到錯(cuò)誤SQLSTATE[HY000]： 常規(guī)錯(cuò)誤： 1005 無(wú)法創(chuàng)建表 。（錯(cuò)誤：150“外鍵約束格式不正確”）（SQL：更改表在刪除級(jí)聯(lián)時(shí)添加約束外鍵 （） 引用 （））...ordercustomizesordercustomizesordercustomizes_userorder_id_foreignuserorder_iduserordersorder_number    Schema::create('ordercustomizes', function (Blueprint $table) {        $table->engine = 'InnoDB';        $table->increments('id');        $table->string('userorder_id');        $table->integer('product_id')->unsigned();        $table->integer('customizetitle_id')->unsigned();        $table->integer('customizeproduct_id')->unsigned();        $table->timestamps();            $table->foreign('userorder_id')            ->references('order_number')            ->on('userorders')            ->onDelete('cascade');主表：   Schema::create('userorders', function (Blueprint $table) {        $table->engine = 'InnoDB';        $table->increments('id');        $table->integer('product_id')->unsigned();        $table->integer('storeinfo_id')->unsigned();        $table->integer('user_id')->unsigned();         $table->string('order_number');