How to limit the size of association in grails?

问题

I have a grails domain class as below :

 class Order {
   String orderId = 'OD' + System.nanoTime().toString()
   Date orderedDate
   String itemName
   List bids;
   static hasMany = [ bids: Bid ;likedUsers: User,]
   static belongsTo =[owner:User]
  }

 class Bid {
  Integer amount
  User bidedUser
     static belongsTo = [Order]
  }
   class User {
     String username
     String password
     String emailId
     List orders
     static hasMany = [orders:Order]
     }

What I am trying to do is , to query for an order with bits with maxResult of 10 as like

 def critObj = Order.createCriteria() 
     critObj.list{
       eq("id" ,1)
       bids {
         maxResult(10) //Trying to fetch only 10 records
        }
    }

How can I load only 10 bits(associations) , is it possible? . Or My design of domain class is wrong?

回答1:

I think this should work:

def results = Bid.withCriteria {
    order {
        eq 'id', 1
    }
    projections {
        property 'order'
    }
    maxResults 10
}

But please note that you have to change your Bid domain class to add the relation in the other way from Bid to Order:

class Bid {
    ...
    static belongsTo = [order: Order]
}

来源：https://stackoverflow.com/questions/24100227/how-to-limit-the-size-of-association-in-grails