需要帮助优化使用 Restrictions.In(..) 的 NHibernate 条件查询

Question

我试图弄清楚是否有一种方法可以通过子查询或其他更优化的方式严格使用 Criteria 和 DetachedCriteria 执行以下操作。 NameGuidDto 只不过是一个具有字符串和 Guid 属性的轻量级对象。

public IList<NameGuidDto> GetByManager(Employee manager)
{
    // First, grab all of the Customers where the employee is a backup manager.
    // Access customers that are primarily managed via manager.ManagedCustomers.
    // I need this list to pass to Restrictions.In(..) below, but can I do it better?
    Guid[] customerIds = new Guid[manager.BackedCustomers.Count];

    int count = 0;
    foreach (Customer customer in manager.BackedCustomers)
    {
        customerIds[count++] = customer.Id;
    }

    ICriteria criteria = Session.CreateCriteria(typeof(Customer))
                                .Add(Restrictions.Disjunction()
                                                 .Add(Restrictions.Eq("Manager", manager))
                                                 .Add(Restrictions.In("Id", customerIds)))
                                .SetProjection(Projections.ProjectionList()
                                                          .Add(Projections.Property("Name"), "Name")
                                                          .Add(Projections.Property("Id"), "Guid"))

    // Transform results to NameGuidDto
    criteria.SetResultTransformer(Transformers.AliasToBean(typeof(NameGuidDto)));

    return criteria.List<NameGuidDto>();
}

Answer 1

return Session.CreateCriteria<Customer>()
    .CreateAlias("BackupManagers", "bm", LeftOuterJoin)
    .Add(Restrictions.Disjunction()
        .Add(Restrictions.Eq("Manager", manager))
        .Add(Restrictions.Eq("bm.Id", manager.Id)))
    .SetProjection(Projections.Distinct(Projections.ProjectionList()
        .Add(Projections.Property("Name"), "Name")
        .Add(Projections.Property("Id"), "Guid")))
    .SetResultTransformer(Transformers.AliasToBean(typeof(NameGuidDto)))
    .List<NameGuidDto>();

我在那里扔了一个不同的，因为我不确定是否有可能让备份和主要是同一个人。