NHibernate QueryOver標准

Question

我仍在學習NHibernate，並且想知道是否有人可以幫助我將以下條件轉換為QueryOver 。

我認為我的基礎知識不高，但是查詢子集合並添加別名時我有點迷茫。 發布的條件查詢確實返回了預期的數據，但是我不確定我對條件格式的所有魔術字符串的適應程度如何。

return Session.CreateCriteria<Person>()
    .Add(Restrictions.Eq("FirstName", firstName))
    .Add(Restrictions.Eq("LastName", lastName))
    .CreateCriteria("PartyContactMechanisms")
    .CreateAlias("ContactMechanism", "c")
    .Add(Restrictions.Eq("c.ElectronicAddressString", emailAddress))
    .UniqueResult<Person>();

編輯：我能夠使用以下QueryOver返回所需的結果。 我以為我會發布解決方案，以防其他人解決。 也歡迎您提供任何有關改進此代碼的建議。

Person personAlias = null;
        ElectronicAddress emailAlias = null;
        PartyContactMechanism partyContactMechAlias = null;

        return Session.QueryOver(() => personAlias)
            .Where(p => p.FirstName == firstName)
            .And(p => p.LastName == lastName)
            .JoinQueryOver(() => personAlias.PartyContactMechanisms, () => partyContactMechAlias)
            .JoinAlias(() => partyContactMechAlias.ContactMechanism, () => emailAlias)
            .Where(() => emailAlias.ElectronicAddressString == emailAddress)
            .SingleOrDefault<Person>();

Answer 1

它可能看起來像這樣：

// these are aliases, which we can/will use later, 
// to have a fully-type access to all properties
Person person = null;
PartyContactMechanism partyContactMechanisms = null;
ContactMechanism contactMechanism = null;

// search params
var firstName = ..;
var lastName  = ..;
var emailAddress = ..;

var query = session.QueryOver<Person>(() => person)
    // the WHERE
    .Where(() => person.FirstName == firstName)
    // the And() is just more fluent eq of Where()
    .And(() => person.LastName == lastName)
    // this collection we will join as criteria
    .JoinQueryOver(() => person.PartyContactMechanism, () => partyContactMechanisms)
    // its property as alias
    .JoinAlias(() => partyContactMechanisms.ContactMechanism, () => contactMechanism )
    // final filter 
    .Where(() => contactMechanism.Code == emailAddress)
    // just one result
    .Take(1)
    ;


var uniqueResult = query
    .List<Person>()
    .SingleOrDefault();

有關更多信息，請在這里深入了解：

• 第16章QueryOver查詢
• 或在這里

注意：還檢查子查詢，因為查詢“集合”時這些子查詢要好得多。 只需搜索它們...並將它們用作子選擇WHERE parentId IN (SELECT parentId FROM ChildTable...