NHibernate QueryOver标准

Question

我仍在学习NHibernate，并且想知道是否有人可以帮助我将以下条件转换为QueryOver 。

我认为我的基础知识不高，但是查询子集合并添加别名时我有点迷茫。 发布的条件查询确实返回了预期的数据，但是我不确定我对条件格式的所有魔术字符串的适应程度如何。

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>();

编辑：我能够使用以下QueryOver返回所需的结果。 我以为我会发布解决方案，以防其他人解决。 也欢迎您提供任何有关改进此代码的建议。

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

它可能看起来像这样：

// 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();

有关更多信息，请在这里深入了解：

• 第16章QueryOver查询
• 或在这里

注意：还检查子查询，因为查询“集合”时这些子查询要好得多。 只需搜索它们...并将它们用作子选择WHERE parentId IN (SELECT parentId FROM ChildTable...