Question

我试图通过第3层关系对数据进行排序，但我无法让它发挥作用。我已成功使用别名来查询2级关系。这就是我的查询设置方法

def query = Application.where {}

query.createAlias("applicationDegrees", "appDegrees");
query.createAlias("applicationDegrees.degree", "degree");
query.createAlias("applicationDegrees.applicationDegreeMajors", "appMajors");
query.createAlias("applicationDegrees.applicationDegreeMajors.major", "major");


return query.list([sort: "degree.code", order: "desc"]); //WORKS
return query.list([sort: "major.code", order: "desc"]);  //DOES NOT WORK

从上面的示例代码中可以看出，我可以按appDegrees和degree排序。当我尝试更进一步，根据appMajors或major的关系进行排序时，appDegrees的关系不能正确排序。根本不应用任何排序，但也不会抛出任何错误消息。

这是我的数据模型

class Application {
    Set<ApplicationDegree> applicationDegrees = []

    static hasMany = [applicationDegrees: ApplicationDegree]
}

class ApplicationDegree {
    Application app
    Degree degree
    Set applicationDegreeMajors = []

    static hasMany = [applicationDegreeMajors: ApplicationDegreeMajor]
    static belongsTo = [Application, Degree]
}

class ApplicationDegreeMajor {
    ApplicationDegree applicationDegree
    Major major

    static belongsTo = [ApplicationDegree, Major]
}

如何创建别名以便我可以按Major排序？

Grails 3.1.4

Answer 1

我想可以在这里找到答案（和解决方法）：https://forum.hibernate.org/viewtopic.php?t=947709

似乎不支持嵌套别名，因此我建议将其替换为：

query.createAlias("applicationDegrees", "appDegrees");
query.createAlias("appDegrees.degree", "degree");
query.createAlias("appDegrees.applicationDegreeMajors", "appMajors");
query.createAlias("appMajors.major", "major");

Grails：多个嵌套关系的分离标准

1 个答案: