Nhibernate在带有联接的QueryOver中返回特定类型的联合子类 [英] Nhibernate return a specific type of union subclass in a QueryOver with join
问题描述
这是我当前的邻苯甲酸酯查询
This is my current nhibenate query
MappedHSPItemDto itemDtoAlias = null;
TItem itemAlias = default(TItem);
return
Session.QueryOver<TMapItem>()
.JoinAlias(x => x.Item, () => itemAlias, JoinType.InnerJoin)
.Where(x => x.HealthServiceProvider == hsp)
.SelectList(list => list
.Select(x => x.Id).WithAlias(() => itemDtoAlias.Id)
.Select(x => x.Version).WithAlias(() => itemDtoAlias.Version)
.Select(x => x.HSPItemCode).WithAlias(() => itemDtoAlias.HSPItemCode)
.Select(x => x.HSPItemName).WithAlias(() => itemDtoAlias.HSPItemName)
.Select(x => itemAlias.Code).WithAlias(() => itemDtoAlias.CirrusItemCode)
.Select(x => itemAlias.Name).WithAlias(() => itemDtoAlias.CirrusItemName)
)
.TransformUsing(Transformers.AliasToBean<MappedHSPItemDto>()).List<MappedHSPItemDto>();
返回此sql查询
SELECT
this_.Id as y0_,
this_.Version as y1_,
this_.HSPItemCode as y2_,
this_.HSPItemName as y3_,
itemalias1_.Code as y4_,
itemalias1_.Name as y5_
FROM
HSPMedicineMapping this_
inner join
(
select
Id,
Version,
Code,
Name,
GenericName,
1 as clazz_
from
Medicine
union
all select
Id,
Version,
Code,
Name,
null as GenericName,
2 as clazz_
from
AssetEquipment
union
all select
Id,
Version,
Code,
Name,
null as GenericName,
3 as clazz_
from
[Procedure]
union
all select
Id,
Version,
Code,
Name,
null as GenericName,
4 as clazz_
from
Supply
union
all select
Id,
Version,
Code,
Name,
null as GenericName,
5 as clazz_
from
Examination
union
all select
Id,
Version,
Code,
Name,
null as GenericName,
6 as clazz_
from
OtherItem
) itemalias1_
on this_.ItemId=itemalias1_.Id
WHERE
this_.HealthServiceProviderId = @p0;
@p0 = 12 [Type: Int64 (0)]
基本上，这里发生的事情是我加入了union子类，并在查询中加入了Item类型的所有子类.
basically what is happening here is im joining to a unionsubclass and on the query its including all subclass of the Item type.
有没有一种方法可以只在查询中包括特定类型的子类?
Is there a way to just include the specific type of subclass in a query?
我使用代码映射，以下是其中一个子类的映射
im using mapping by code, below is the mapping for one of the subclass
public class MedicineMap : UnionSubclassMapping<Medicine>
{
public MedicineMap()
{
Property(p => p.Code, Rules.CodeRule);
Property(p => p.Name, Rules.StrLength255AndNotNull);
Property(p => p.GenericName, Rules.StrLength400AndNullable);
Bag(x => x.HMOMedicineMappings, bag =>
{
bag.Inverse(true);
bag.Key(k => k.Column(col => col.Name("ItemId")));
}, a => a.OneToMany());
Bag(x => x.HSPMedicineMappings, bag =>
{
bag.Inverse(true);
bag.Key(k => k.Column(col => col.Name("ItemId")));
}, a => a.OneToMany());
}
}
这是我的实体
public abstract class Item : EntityBase
{
public virtual string Code { get; set; }
public virtual string Name { get; set; }
}
public class Medicine : Item
{
public Medicine()
{
HSPMedicineMappings = new List<HSPMedicineMapping>();
HMOMedicineMappings = new List<HMOMedicineMapping>();
}
public virtual string GenericName { get; set; }
public virtual IList<HSPMedicineMapping> HSPMedicineMappings { get; set; }
public virtual IList<HMOMedicineMapping> HMOMedicineMappings { get; set; }
}
public class AssetEquipment : Item
{
public AssetEquipment()
{
HSPAssetEquipmentMappings = new List<HSPAssetEquipmentMapping>();
HMOAssetEquipmentMappings = new List<HMOAssetEquipmentMapping>();
}
public virtual IList<HSPAssetEquipmentMapping> HSPAssetEquipmentMappings { get; set; }
public virtual IList<HMOAssetEquipmentMapping> HMOAssetEquipmentMappings { get; set; }
}
public abstract class HSPItemMapping : EntityBase
{
public virtual HealthServiceProvider HealthServiceProvider { get; set; }
public virtual string HSPItemCode { get; set; }
public virtual string HSPItemName { get; set; }
public virtual Item Item { get; set; }
}
public class HSPMedicineMapping : HSPItemMapping
{
}
推荐答案
如果TMapItem是特定类型，NH将仅查询TMapItem的表.但是，正如您在注释中所说的那样，在加入Type时是未知的，因此所有表都被合并.为避免这种情况，您必须在保存该类型的外键旁边插入一列.我不确定，但是NH应该优化查询.
if TMapItem is the specific type NH will only query the table of TMapItem. However as you said in comment when joining the Type is unknown hence all tables are unioned. To avoid this you have to introduce a column next to the foreignkey holding the type. Im not sure but NH should optimise the query then.
// mapping using FluentNhibernate
ReferencesAny(x => x.Property)
.KeyType()
.MetaValue<Subclass1>("foo")
.MetaValue<Subclass2>("bar");
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