Grails save（）域对象实际上是一个Select吗？

Question

我正在尝试将JSONObject发布到我的groovy控制器上。我可以传递对象，查看JSON数据，然后从中创建一个域对象。当我保存它以写入数据库时​​，它会执行Select。

def save = {
    def input = request.JSON
    def instance = new Customers(input)
    instance.save()
}   

这是我的debug sql输出

Hibernate: 
select
    this_.customers_id as customers1_237_0_,
    this_.customers_default_address_id as customers2_237_0_,
    this_.customers_dob as customers3_237_0_,
    this_.customers_email_address as customers4_237_0_,
    this_.customers_email_address2 as customers5_237_0_,
    this_.customers_fax as customers6_237_0_,
    this_.customers_firstname as customers7_237_0_,
    this_.customers_gender as customers8_237_0_,
    this_.customers_lastname as customers9_237_0_,
    this_.customers_membertype as customers10_237_0_,
    this_.customers_memo1 as customers11_237_0_,
    this_.customers_mname as customers12_237_0_,
    this_.customers_newsletter as customers13_237_0_,
    this_.customers_password as customers14_237_0_,
    this_.customers_point_date as customers15_237_0_,
    this_.customers_telephone as customers16_237_0_,
    this_.customers_total_points as customers17_237_0_,
    this_.customers_username as customers18_237_0_ 
from
    customers this_ 
where
    this_.customers_username=?

不知道会造成什么。

Answer 1

您似乎对用户名有唯一约束。 Grails执行select来检查唯一性，因为假设读取一行是一个轻量级动作，并且最好触发一个唯一约束违例和异常。

另一种方法是删除域类中的唯一约束，并在数据库中手动添加唯一约束。

Answer 2

你有没有试过像：

Customers cust = new Customers(input);
println ("cust = "+cust);
cust.save();