[英]NHibernate fetch creates right query and then performs N+1
我有三個實體,配置為
Contact
HasOne(e => e.User).PropertyRef(e => e.Contact).Cascade.All();
User
HasMany(e => e.Requests);
References(e => e.Contact);
Request
References(e => e.User);
然后我這樣查詢:
CurrentSession.Query<Request>()
.Fetch(x => x.User)
.ThenFetch(x => x.Contact)
.ToList();
看起來Fetch正在運行,因為在第一個選擇中,我看到了所有連接的表(為簡潔起見,省略了其他字段):
SELECT request0_.Id as Id128_0_,
user1_.Id as Id131_1_,
contact2_.Id as Id77_2_,
FROM requests request0_
left outer join users user1_
on request0_.user_id = user1_.Id
left outer join contacts contact2_
on user1_.contact_id = contact2_.Id
然后由於某些原因遵循N + 1選擇,我不明白,也不知道如何解決此問題:
SELECT user0_.Id as Id131_0_,
FROM users user0_
WHERE user0_.contact_id = 200 /* @p0 - contact_id */
目前,這是NHibernate中的錯誤 。
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