问Laravel数据库迁移错误的表定义

EN

public function up()
    {
        Schema::create('materials', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name',60);
            $table->integer('category_id',10);
            $table->integer('low_bulk',10);
            $table->integer('high_bulk',10);
            $table->integer('order_level',10);
            $table->decimal('unit_price',10,2);
            $table->string('description');
            $table->timestamps();
        });
    }

SQLSTATE[42000]: Syntax error or access violation: 1075 Incorrect table definition; there can be only one auto column and it must be
defined as a key