[英]NHibernate Select N+1 and Recursive
I've got a couple of data classes: 我有几个数据类:
public class RecordGroup
{
public virtual DataRecord RootDataRecord;
}
public class DataRecord
{
public virtual string Name { get; set; }
public virtual RecordGroup RecordGroup { get; set; }
public virtual IList<DataRecord> Children { get; set; }
public virtual DataRecord Parent { get; set; }
public virtual IList<DataProperty> DataProperties { get; set; }
public virtual IList<Foto> Fotos { get; set; }
}
public class DataProperty
{
public virtual string Name { get; set; }
public virtual string Value { get; set; }
public virtual IList<Foto> Fotos { get; set; }
}
public class Foto
{
public virtual string Name { get; set; }
public virtual byte[] Data { get; set; }
}
So 1 RecordGroup is "connected" to several DataRecords, having several children (which again got children etc.) each of them having several Properties and Fotos. 因此,一个RecordGroup被“连接”到多个DataRecords,有几个子级(又有子级等),每个子级都有几个Properties和Fotos。 I need all the DataRecords including Children, Properties and Fotos according to a certain RecordGroup.
我需要根据某个RecordGroup的所有DataRecords,包括Children,Properties和Fotos。
Doing this within raw SQL is a simple statement with a few joins, but when i try to do this with linq and nhibernate it results in 1500 Select N+1 Statements, and an enormous slowdown. 在原始SQL中执行此操作是一个简单的语句,其中包含一些联接,但是当我尝试使用linq和nhibernate进行此操作时,它导致1500个Select N + 1语句,并且运行速度非常慢。
I already tried .FetchMany( x => x.Children );
我已经尝试过
.FetchMany( x => x.Children );
How is it possible to get the whole "datatree" of 1 Recordgroup within 1 Query? 如何在1个查询中获得1个记录组的整个“数据树”?
Thanks in advance!!!! 提前致谢!!!!
I think, you need something like this: 我认为,您需要这样的东西:
var recordGroupId = // your recordGroup Id
Session.QueryOver<DataRecord>()
.Where(dataRecord.RecordGroup.Id == recordGroupId)
.Fetch(dataRecord => dataRecord.Children).Eager
.Fetch(dataRecord => dataRecord.DataProperties).Eager
.Fetch(dataRecord => dataRecord.Fotos).Eager
.TransformUsing(Transformers.DistinctRootEntity)
.List<DataRecord>();
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