如何在Grails域类中调整Map的约束/ DB映射 [英] How to adjust constraints / DB mapping for Map within grails domain class

问题描述

下面的grails域类：

  class MyClass {
 Map myMap 
} 
  

现在，对于myMap，grails会自动为地图中的元素创建一个新表。但是如果我添加太长的元素（例如1024个字符），我会得到一个DB错误。

我可以告诉grails，

我已经尝试过了

  static constraints = {
 myMap（maxSize：1024）
} 
  

这不起作用（如预期的那样，因为maxSize应该引用Map的值，而不是Map本身）。

通过约束，也许有办法通过

 静态映射{...} 
  
 
 
 
？
解决方案
我成功使用的是将地图推送到协作网域类的集合中。
  class DynaProperty {
 String name 
字符串值
 
 static belongsTo = MyClass 
 static constraints = {
 value（maxSize：4000）//或任何数字适当
} 
} 
  
然后在MyClass中：
  class MyClass {
 static hasMany = [dynaProperties：DynaProperty] 
} 
  
这是几乎一个地图，它允许您使用动态查找器来拉取单个条目。
 
Following grails domain class:
class MyClass {
  Map myMap
}
Now for myMap, grails automatically creates a new table for the elements in the map. However if I add elements which are too long (e.g. 1024 characters), I get a DB error.

Can I somehow tell grails to make the respective column in myMap's table big enough to allow for larger Strings, or do I have to do this manually in the DB?

I already tried
static constraints = {
  myMap(maxSize:1024)
}
which doesn't work (as expected because maxSize should refer to the Map's values and not to the Map itself).

If not via constraints, maybe there's a way to do it via
static mapping { ... }
?
解决方案
An alternative approach I used successfully was to push the map out into a collection of a collaborator domain class.
class DynaProperty {
    String name
    String value

    static belongsTo = MyClass
    static constraints = {
        value(maxSize:4000)  //Or whatever number is appropriate
    }
}
And then in MyClass:
class MyClass {
    static hasMany = [dynaProperties:DynaProperty]
}
This is almost a map, and it gives you the ability to use dynamic finders to pull up an individual entry.

                        
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