QueryOver order by join alias: 无法绑定多部分标识符答案

【问题标题】：QueryOver order by joined alias: The multi-part identifier could not be boundQueryOver order by join alias: 无法绑定多部分标识符
【发布时间】：2014-03-24 17:10:53
【问题描述】：

我在查询时遇到问题：

Company thirdParty = null;
var thirdParties = Session.QueryOver<ThirdPartyCompany>()
                          .JoinAlias(x => x.Company, () => thirdParty)
                          .WhereRestrictionOn(x => x.Domain.Id)
                          .IsIn(domainIds)
                          .OrderBy(() => thirdParty.Name).Asc
                          .Select(x => x.Company)
                          .List<Company>();

ThirdpartyCompany 实体看起来像这样，本质上是一个映射的多对多表：

public class ThirdPartyCompany
{
    public virtual Domain Domain { get; set; }
    public virtual Company Company { get; set; }

    // ... removed equality overrides for readability
}

我遇到的问题是订单部分。如果我跳过排序，则查询有效。但是通过订购我得到一个例外，上面写着{"The multi-part identifier \"thirdparty1_.Name\" could not be bound."}。我也尝试过.OrderByAlias( )，但也没有成功...

编辑（添加映射）：

public class ThirdPartyCompanyMapping : ClassMapping<ThirdPartyCompany>
{
    public ThirdPartyCompanyMapping()
    {
        Table("ThirdPartyCompany");
        ComposedId(mapping => mapping.ManyToOne(x => x.Domain, m =>
        {
            m.Column("DomainId");
            m.NotNullable(true);
        }));
        ComposedId(mapping => mapping.ManyToOne(x => x.Company, m =>
        {
            m.Column("CompanyId");
            m.NotNullable(true);
        }));
    }
}
public class CompanyMapping : ClassMapping<Company>
{
    public CompanyMapping()
    {
        Property(x => x.Name, m => m.NotNullable(true));
        Property(x => x.Type, m => m.NotNullable(true));
        ManyToOne(x => x.Domain, m => m.NotNullable(false));
    }
}
public class DomainMapping : ClassMapping<Domain>
{
    public DomainMapping()
    {
        Property(x => x.Name, m =>
        {
            m.NotNullable(true);
            m.Unique(true);
        });
        Set(x => x.ThirdParties, m =>
        {
            m.Table("ThirdPartyCompany");
            m.Key(x => x.Column("DomainId"));
        }, c => c.ManyToMany());

        //... removed other mappings for readability
    }
}

【问题讨论】：

你能发布你的映射吗？
别生气，但这里有一个“是否已插入”的问题：Name 列是否存在于Company 表中？也就是说，这个 SQL 查询 SELECT TOP 1 Name FROM Company; 运行时没有错误吗？
你能发布 NHibernate 试图执行的 SQL 吗？
@DanielSchilling，是的，查询返回一行（有一个名称）。
@DanielSchilling，sql 看起来像这样：SELECT this_.CompanyId as y0_ FROM ThirdPartyCompany this_ WHERE this_.DomainId in (@p0) ORDER BY thirdparty1_.Name asc

标签： nhibernate queryover

【解决方案1】：

我找到了适合我的解决方法。我将查询一分为二（其中一个是分离的）：

var thirdPartiesInDomain = QueryOver.Of<ThirdPartyCompany>()
                                    .WhereRestrictionOn(x => x.Domain.Id)
                                    .IsIn(domainIds)
                                    .Select(x => x.Company.Id);

var thirdParties = Session.QueryOver<Company>()
                          .WithSubquery.WhereProperty(x => x.Id)
                          .In(thirdPartiesInDomain)
                          .OrderBy(x => x.Name).Asc
                          .List();

【讨论】：