Question

这个问题接近但与此处的问题不同： NHibernate Query across multiple tables

基本上，我的问题是给出以下模型，我将如何查询当前的狗是否具有名称“foo”或过去的狗是否具有名称“foo”（分离）。 基本上我对于CurrentDog有多对一关系，对PastDogs有多对多关系。

public class Dog {
    public string name {get; set;}
}

public class Owner {
    public string firstname {get; set;}
    public string lastname {get; set;}
    public Dog CurrentDog {get; set;}
    public Dog[] PastDogs {get; set;}
}

我猜SQL应该是这样的：

    SELECT o.* FROM owners AS o
    INNER JOIN dogs AS cd ON o.current_dog_id = cd.id
    INNER JOIN owner_past_dog_maps AS pd ON o.id = pd.owner_id
    INNER JOIN dogs AS d ON pd.dog_id = d.id
    WHERE d.name = 'foo' 
    OR cd.name = 'foo'

希望有意义......如果有人问，我会尝试澄清它。

Answer 1

我尝试使用QueryOver和别名

来解决它

Owner myOwner = null;
Dog myCurrentDog = null; 
Dog myPastDogs = null;

var sax = _HibSession.QueryOver<Owner>(() => myOwner)
                .JoinAlias(() => myOwner.CurrentDog, () => myCurrentDog, JoinType.InnerJoin)
                .JoinAlias(() => myOwner.PastDogs, () => myPastDogs , JoinType.InnerJoin)
                .Where(Restrictions.Disjunction()
                    .Add(Restrictions.EqProperty(myCurrentDog.Name,"foo"))
                    .Add(Restrictions.EqProperty(myPastDogs.Name,"foo"))                    
                )                                            
                .List<Owner>();

我希望它有用！

Answer 2

我想我应该开始说我是NHibernate的新手。我不明白的是NHibernate中的别名，你创建的别名不是为了表，而是为了关系和属性名。看哪，这个解决方案将归还所有拥有或拥有狗名foo的所有者：

    var output = Session.CreateCriteria<Owner>()
        .CreateAlias("CurrentDog", "cd")
        .CreateAlias("PastDogs", "pd")
        .Add
        (
            Restrictions.Disjunction()
            .Add(Restrictions.Eq("cd.Name", "foo"))
            .Add(Restrictions.Eq("pd.Name", "foo"))
        )
        .List<Owner>();

Nhibernate Disjunction（“OR”）查询多对一和多对多关系

2 个答案: