问题描述
我有这些遗留表,我可以通过nhibernate访问,基本的一个实体访问是可以的,但是我真的需要使连接正常工作.
I have these legacy tables which i’m accessing by nhibernate, basic one entity access is fine but i would really need to get joins working.
理想情况下,我将具有主键和外键来定义联接,但是由于这些是遗留表,因此我只有作为表索引的复合ID,这些索引出于性能原因而使用,因此我无法更改.
Ideally i would have primary and foreign key to define the joins but as these are legacy tables i only have composite ids that are the indexes for the tables, indexes these have been used for performance reason so i cannot change.
无论如何我都有JobHeader表和Property表
Anyways i have JobHeader table and Property table
JobHeader映射目前看起来像这样:
JobHeader mapping looks something like this at the moment:
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="JobHeader " dynamic-update="true" table="JOB_HEADER">
<composite-id>
<key-property name="Company" column="JBH_COMPANY" type="String(6)" />
<key-property name="ContractRef" column="JBH_CONTRACT_REF" type="String(10)" />
<key-property name="JobRef" column="JBH_JOB_REF" type="String(10)" />
<key-property name="Status" column="JBH_STATUS" type="String(10)" />
</composite-id>
<property name="RowId" column="TK_ROWID" type="Int32" not-null="true" />
<property name="PropRef" column="JBH_PROP_REF" type="String(20)" not-null="false" />
</class>
</hibernate-mapping>
属性映射如下:
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="Property" dynamic-update="true" table="PROPERTY">
<composite-id>
<key-property name="Company" column="PRP_COMPANY" type="String(6)" />
<key-property name="Reference" column="PRP_REFERENCE" type="String(20)" />
</composite-id>
<property name="RowId" column="TK_ROWID" type="Int32" not-null="true" />
<property name="Name" column="PRP_NAME" type="String(40)" not-null="false" />
</class>
</hibernate-mapping>
在Jobheader中,它使用"PropRef"保存属性"Reference".
In Jobheader it uses "PropRef" to hold the Property "Reference".
我想创建一个新的映射文件,称为JobHeaderJoinedProperty因此可能看起来像这样:
I would like to create a new mapping file that would be called JobHeaderJoinedPropertyAnd so would perhaps look something like this:
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2">
<class name="JobHeaderJoinProperty" dynamic-update="true" table="JOB_HEADER">
<composite-id>
<key-property name="Company" column="JBH_COMPANY" type="String(6)" />
<key-property name="ContractRef" column="JBH_CONTRACT_REF" type="String(10)" />
<key-property name="JobRef" column="JBH_JOB_REF" type="String(10)" />
<key-property name="Status" column="JBH_STATUS" type="String(10)" />
</composite-id>
<property name="RowId" column="TK_ROWID" type="Int32" not-null="true" />
<property name="PropRef" column="JBH_PROP_REF" type="String(20)" not-null="false" /> </class>
<bag name="Property" fetch="join" >
<key column="Reference" property-ref="PropRef" />
<one-to-one class="Property"/>
</bag>
</class>
</hibernate-mapping>
然后希望我的JobHeaderJoinedProperty实体能够访问其中的Property实体:
Then hoping my JobHeaderJoinedProperty entity would then be able to access the Property entity with this in it:
public virtual Property Property
{
get
{
return this.property;
}
set
{
this.property = value;
}
}
通过nhibernate连接两个旧表应该不是很棘手吧!!
Joining two legacy tables via nhibernate shouldn’t be too tricky right?!
我真的只想复制一个内部联接,其中sql将是这样的:
I really just want to replicate an inner join where the sql would be like this:
Select * from job_header inner join property on property.reference = job_header.propref
推荐答案
您所追求的不是一对一的映射吗?
Isn't a one-to-one mapping all you are after?
<one-to-one
name="PropertyName" (1)
class="Property" (2)
cascade="all|none|save-update|delete" (3)
constrained="true|false" (4)
fetch="join|select" (5)
property-ref="PropertyNameFromAssociatedClass" (6)
access="field|property|nosetter|ClassName" (7)
/>
所以您的情况应该是
<one-to-one
name="Property"
class="ClassName"
property-ref="PropRef"
/>
来源 http://www.nhforge.org/doc/nh/en/#mapping-declaration-onetoone
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