我有一个带有User
和Group
域对象的grails应用程序。 User
具有许多Group
对象,而Group
对象包含许多User
对象:
class User implements Serializable {
static constraints = {
usergroups nullable: true
}
static mapping = {
usergroups cascade: 'all-delete-orphan'
}
static hasMany = [
usergroups: Group
]
static mappedBy = [
usergroups : "creator"
]
}
class Group {
static belongsTo = [
creator : User
]
static hasMany = [
members : User
]
static constraints = {
creator nullable: false
members nullable: true, maxSize: 100
}
}
给定一个
Group
对象,我可以使用max
,offset
和sortBy
参数检索成员吗?就像是...def members = User.where {
/* how to specify only the users in 'group.members'? */
}.list(
max: max,
offset: offset,
sortBy : sortBy
);
编辑
为了尝试解决该问题,我已将
User
类更改为包含joinedgroups
字段...class User implements Serializable {
static constraints = {
usergroups nullable: true
joinedgroups nullable: true
}
static mapping = {
usergroups cascade: 'all-delete-orphan'
}
static hasMany = [
usergroups: Group
joinedgroups: Group
]
static mappedBy = [
usergroups : "creator",
joinedgroups : "creator" // if I don't add this Grails complains there is no owner defined between domain classes User and Group.
]
}
但是现在当我尝试检索应用程序另一部分中所有用户的
usergroup
对象时,仅返回一个用户组... def groups = Group.where {
creator.id == user.id
}.list(max: max, offset: offset, sort: sortBy); // should return 3 groups but now only returns 1
此查询之前有效,因此在
mappedby
中添加额外的User
条目可能导致了此问题。 mappedby
中的新User
字段不正确吗?
最佳答案
如果包含用户的所有组都保存在usergroups
字段中,则可以使用:
def query = User.where {
usergroups { id == myGroup.id }
}
def users = query.list(max: 10, offset: 0, sort : "id")
关于grails - 如何使用Grails ORM检索具有max,offset和sort参数的列表,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/32310236/