Mapping native sql to Entity with NHibernate

Question

Is possible to map a raw sql to an entity with NHibernate?

Like the following:

C# entity:

public virtual IList<Result> MyResult { get; set; }

Hbm.xml:

<bag name="MyResult">
    <my-custom-sql type="Result">
        SELECT * FROM ResultTable where MyComplexCondition = true
    </my-custom-sql>
</bag>

Result has it own hbm.xml. Is possible to do what I want to achieve?

Community · Accepted Answer · 2017-05-23 12:23:07Z

1

There is a feature, called <subselect>. See more here

How to map an NHibernate entity to a query

That could be applied on <class> as well as on <bag>. This could be the way how to use it on a bag for MyEntity which has collection of Languages

<bag name="Languages" lazy="true" batch-size="25" 
     mutable="false" >
  <subselect>
    SELECT MyEntity_ID, Language_ID, IsNative FROM Languages
  </subselect>
  <key column="MyEntity_ID" />
  <composite-element class="Language">
    <parent name="MyEntity"/>
    <many-to-one not-null="true" name="Language" class="Language" column="Language_ID" />
    <property not-null="true" name="IsNative" column="IsNative"/>
  </composite-element>
</bag>

This of course, should be used for readonly (immutable) solutions

edited May 23, 2017 at 12:23

CommunityBot

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answered Nov 3, 2015 at 5:44

Radim Köhler

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4 Comments

Arthur Castro Over a year ago

What is the parent tag?

Radim Köhler Over a year ago

Just optional.. just a way how NHibernate could give your collection items BACK reference to collection holder/parent. Cool and sexy feature ;)

Arthur Castro Over a year ago

One last question (it's really hard to find someone who understand this aspect of NHibernate): Can I map some collection inside a composite-element tag? A bag, for example, that have a key pointing to an Id property of the composite-element.

Radim Köhler Over a year ago

NO. (sorry) Check the doc 7.2. Collections of dependent objects: "Composite elements may contain components but not collections" But, regardless this small NO, enjoy mighty NHibernate ;) it is amazing tool

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