在Grails Domain Class中为Date字段设置默认值 [英] Setting default value for Date field in Grails Domain Class
问题描述
我试图为Domain类中的 Date
字段设置默认值。
I'm trying to set a default value for a Date
field in a Domain class.
I可以在映射
配置中使用 defaultValue
,但它不适用于 Date
字段(我试过它在字符串
和整数
,它工作正常)。
I can use defaultValue
in the mapping
configuration but it doesn't work with Date
fields (I've tried it on String
and Integer
and it works fine).
这是一个例子:
This is an example:
class Something {
Date myField
static mapping = {
myField defaultValue: new Date()
}
}
此代码失败,因为Hibernate生成的CREATE语句不正确。它是这样的:
This code fails because the CREATE statement that Hibernate generates is incorrect. It is something like:
... my_field datetime default Mon Nov 25 17:59:08 UYST 2013 not null ...
推荐答案
您可以始终初始化静态初始化程序中的字段或设置构造函数中的值:
You can always initialize the field in the static initializer or set the value in the constructor:
class Something {
// initializer
Date myField = new Date()
// or in the ctor
Something() {
myField = new Date()
}
}
这不会在数据库模式中设置默认值,它只会在创建实例时设置字段的值。如果您希望模式具有默认值,您可以像下面这样使用'defaultValue'映射条目:
This doesn't set a default value in the database schema, it merely sets the value of the field on creation of the instance. If you want the schema to have a default value, you can use the 'defaultValue' mapping entry like so:
class Something {
Date myField
static mapping = {
myField defaultValue: "now()"
}
}
您为默认值设置的值取决于您的数据库供应商。 (注意使用sql now()
方法而不是Java / Groovy new Date()
。
the value you set for the default value is dependent on your database vendor. (notice the use of sql now()
method rather than Java/Groovy new Date()
.
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