NHibernate(+ FluentNhibernate):连接两个独立的表 [英] NHibernate (+ FluentNhibernate) : Join two detached tables

问题描述

我无法在具有相同属性的两个实体上创建联接时遇到问题，但是它们没有映射在一起.

'tI encounter problems to create a join on two entities with a common property but they are not map together.

假设您有一个实体Article，其中包含属性FamilyCode和具有属性Code和Label的实体Family.

Say you have an entity Article which contains a property FamilyCode and an entity Family with properties Code and Label.

在我的映射中，Article没有引用Family，并且我不想更改它(以保持与其他内部和旧方法的兼容性).

In my mappings, Article doesn't reference Family and i don't want to change that (to keep compatibility with others internal and legacy methods).

因此，我无法在Nhibernate中翻译以下查询:

So, i can't translate the below query in Nhibernate :

SELECT f.Code, f.Label
FROM Article a
INNER JOIN Family f ON a.FamilyCode = f.Code
WHERE f.Label LIKE 'p%'

我无法使用JoinQuery，因为我无法注入QueryOver，并且如果使用WithSubquery有可能，我也不知道.

I can't use JoinQuery because i can't inject a QueryOver and i don't konw if it's possible by using WithSubquery.

我尝试使用Future QueryOver和QueryOver，然后在内存中执行Join(每个.List()之后)，但是我的Article行太多，因此需要很长时间.

I tried to Future QueryOver and QueryOver and then perform a Join in memory (after .List() each) but i have too much rows for Article so it takes long time.

您有想法吗?

谢谢.

推荐答案

我们可以使用HQL-但仅 HQL.

We can use HQL - but only HQL.

• 14.2. from子句 (小引用和摘录)

可能会出现多个类，从而导致笛卡尔积或交叉"联接.

Multiple classes may appear, resulting in a cartesian product or "cross" join.

from Formula, Parameter
from Formula as form, Parameter as param

这就是HQL的方式

SELECT f.Code, f.Label
FROM Article a,
     Family f 
WHERE a.FamilyCode = f.Code
AND f.Label LIKE 'p%'

还要检查此 9.3.2. IQuery界面，也可能是 Q& A

Check also this 9.3.2. The IQuery interface and maybe this Q & A

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