C# 具有子计数的NHibernate父列表
我在mysql中使用NHibernate4。我有两张桌子。我的桌子是猫和答案C# 具有子计数的NHibernate父列表,c#,mysql,nhibernate,fluent-nhibernate,sql-to-linq-conversion,C#,Mysql,Nhibernate,Fluent Nhibernate,Sql To Linq Conversion,我在mysql中使用NHibernate4。我有两张桌子。我的桌子是猫和答案 public class cat { [Key] public virtual int id { get; set; } public virtual string catName { get; set; } public virtual IList<answer> answers { get; set; } } public class answer { [Ke
public class cat
{
[Key]
public virtual int id { get; set; }
public virtual string catName { get; set; }
public virtual IList<answer> answers { get; set; }
}
public class answer
{
[Key]
public virtual int id { get; set; }
public virtual int catId { get; set; }
public virtual string detail { get; set; }
public virtual bool stat { get; set; }
[ForeignKey("catId")]
public virtual cat cats { get; set; }
}
这样的结果
id-catName-计数
1-第5册
2-Pc-0
3-英语-22
4-第56条
我也尝试过这个NH查询
public class myClass {
public virtual int count { get; set; }
public virtual cat cats { get; set; }
}
var u = db.CreateCriteria(typeof(cat), "cats")
.CreateAlias("answer", "t2", NHibernate.SqlCommand.JoinType.LeftOuterJoin, Restrictions.Eq("t2.stat", false))
.SetProjection(Projections.ProjectionList()
.Add(Projections.Count("t2.id"), "count")
.Add(Projections.Group<cat>(g => g.id)));
var list = u.SetFetchMode("answer", FetchMode.Eager)
.SetResultTransformer(Transformers.AliasToBean<myClass>())
.List<myClass>();
公共类myClass{
公共虚拟整数计数{get;set;}
公共虚拟猫{get;set;}
}
var u=db.CreateCriteria(类型(cat),“cat”)
.CreateAlias(“answer”,“t2”,NHibernate.SqlCommand.JoinType.LeftOuterJoin,Restrictions.Eq(“t2.stat”,false))
.SetProjection(Projections.ProjectionList()项目)
.Add(Projections.Count(“t2.id”),“Count”)
.Add(projects.Group(g=>g.id));
var list=u.SetFetchMode(“应答”,FetchMode.Eager)
.SetResultTransformer(Transformers.AliasToBean())
.List();
此NHibernate查询返回也回答计数。但是猫总是返回空值。如何查询此结果
编辑1
我可以这样做
public class myClass {
public virtual int count { get; set; }
public virtual catId count { get; set; }
public virtual cat cats { get; set; }
}
cat cats = null;
answer answers = null;
var u = db.QueryOver<cat>(() => cats)
.JoinQueryOver(x => x.answers, () => answers, NHibernate.SqlCommand.JoinType.LeftOuterJoin, Restrictions.Eq("answers.stat", false))
.SelectList(cv => cv
.SelectCount(() => answers.id)
.SelectGroup(c => c.id))
.List<object[]>()
.Select(ax => new myClass
{
count = (int)ax[0],
catId = (int)ax[1],
cats = (cat)db.QueryOver<cat>().Where(w=>w.id==(int)ax[1]).Fetch(fe => fe.answers).Eager.SingleOrDefault()
})
.ToList();
公共类myClass{
公共虚拟整数计数{get;set;}
公共虚拟catId计数{get;set;}
公共虚拟猫{get;set;}
}
cat=null;
答案=空;
变量u=db.QueryOver(()=>cats)
.JoinQueryOver(x=>x.answers,()=>answers,NHibernate.SqlCommand.JoinType.LeftOuterJoin,Restrictions.Eq(“answers.stat”,false))
.选择列表(cv=>cv
.SelectCount(()=>answers.id)
.SelectGroup(c=>c.id))
.List()
.选择(ax=>new myClass
{
计数=(int)ax[0],
catId=(int)ax[1],
cats=(cat)db.QueryOver().Where(w=>w.id==(int)ax[1]).Fetch(fe=>fe.answers).Eager.SingleOrDefault()
})
.ToList();
在您的结果中cats
始终为空,因为ResultTransformer
尝试按属性名称映射属性
请检查您的NHibernate日志文件。您可能会看到查询返回列count
和id
,但是myClass
具有属性count
和cats
编辑:
新建议:
前面的建议无效,因为属性id
的类型为Int32
,无法分配给myClass.cat
(类型为cat
)
如果不需要对myClass
中的cat
-对象进行引用,则可以将其更改为:
public class myClass {
public virtual int count { get; set; }
public virtual int catId { get; set; }
}
有这样的投影:
.Add(Projections.Group<cat>(g => g.id), "catId"));
在查询逻辑之后添加以下内容:
IList<myClassResult> result = new List<myClassResult>();
foreach (var idWithCount in list)
{
result.Add(new myClassResult()
{
cats = catsOnlyList.FirstOrDefault(x => x.id == idWithCount.catId),
count = idWithCount.count
});
}
使用
.Add(Projections.Group(g=>g.id),“cats”);
我可以这样做查询
select count(t2.id) as count, cats.*from cat cats left join answer t2 ON(cats.id=t2.catId and t2.stat=0) GROUP BY(cats.id);
public class myClass {
public virtual int count { get; set; }
public virtual İnt catId { get; set; }
public virtual cat cats { get; set; }
}
cat cats = null;
answer answers = null;
var u = db.QueryOver<cat>(() => cats)
.JoinQueryOver(x => x.answers, () => answers, NHibernate.SqlCommand.JoinType.LeftOuterJoin, Restrictions.Eq("answers.stat", false))
.SelectList(cv => cv
.SelectCount(() => answers.id)
.SelectGroup(c => c.id))
.List<object[]>()
.Select(ax => new myClass
{
count = (int)ax[0],
catId = (int)ax[1],
cats = (cat)db.QueryOver<cat>().Where(w=>w.id==(int)ax[1]).Fetch(fe=>fe.answers).Eager.SingleOrDefault()
})
.ToList();
公共类myClass{
公共虚拟整数计数{get;set;}
公共虚拟İnt catId{get;set;}
公共虚拟猫{get;set;}
}
cat=null;
答案=空;
变量u=db.QueryOver(()=>cats)
.JoinQueryOver(x=>x.answers,()=>answers,NHibernate.SqlCommand.JoinType.LeftOuterJoin,Restrictions.Eq(“answers.stat”,false))
.选择列表(cv=>cv
.SelectCount(()=>answers.id)
.SelectGroup(c=>c.id))
.List()
.选择(ax=>new myClass
{
计数=(int)ax[0],
catId=(int)ax[1],
cats=(cat)db.QueryOver().Where(w=>w.id==(int)ax[1]).Fetch(fe=>fe.answers).Eager.SingleOrDefault()
})
.ToList();
Small Offtopic提示:如果您有选择权,请摆脱criteria api,使用from NHibernateFlorian Lim返回相同的列。给出此错误:无法将System.Int32类型分配给类型为的属性cat@ASPMaker对不起,我没有测试解决方案。我应该知道这是行不通的,因为按ID分组不会得到类型为cat
的结果属性。我修改了我的答案。很抱歉,这个更改只给了我id。我想查询这个问题,它必须返回答案计数和带有答案子项的cat表。我在我的问题中解释了所有这些问题。@ASPMaker在这种情况下,您必须手动将结果组合在一起。请参阅我的第二次编辑。
.Add(Projections.Group<cat>(g => g.id)));
.Add(Projections.Group<cat>(g => g.id), "cats"));
public class myClass {
public virtual int count { get; set; }
public virtual İnt catId { get; set; }
public virtual cat cats { get; set; }
}
cat cats = null;
answer answers = null;
var u = db.QueryOver<cat>(() => cats)
.JoinQueryOver(x => x.answers, () => answers, NHibernate.SqlCommand.JoinType.LeftOuterJoin, Restrictions.Eq("answers.stat", false))
.SelectList(cv => cv
.SelectCount(() => answers.id)
.SelectGroup(c => c.id))
.List<object[]>()
.Select(ax => new myClass
{
count = (int)ax[0],
catId = (int)ax[1],
cats = (cat)db.QueryOver<cat>().Where(w=>w.id==(int)ax[1]).Fetch(fe=>fe.answers).Eager.SingleOrDefault()
})
.ToList();