Select all entities of exact class, but not derived from it using NHibernate Criteria API
I have two cla开发者_Go百科sses: Cat
and DomesticCat
, that extends Cat
.
I want to select all Cat
s, but no oneDomesticCat
. How to do it using NHibernate criteria API?
var nonDomesticCats = session.CreateCriteria<Cat>()
.Add(Restrictions.Eq("class", typeof(Cat)))
.List<Cat>();
class
is a pseudo-property that represents the concrete type of entities in a class hierarchy.
It can be used transparently with any inheritance strategy except implicit.
well it depends on the implementation.
If for example, you have a discriminator column (lets say <discriminator column="CatType" type="string"/>
and the DomesticCat
inheritor class discriminates with value "domestic"
) you could make an query like this
var allCatsButDomestic = nhSes.CreateQuery("from Cat c where c.CatType <> :catType")
.SetString("catType", "domestic")
.List<Cat>();
(in this particular example the Cat abstract class also maps the CatType column to a CatType string property)
EDIT and in Criteria form
var nonDomesticCats = session.CreateCriteria<Cat>()
.Add(Restrictions.Not(Restrictions.Eq("CatType", "domestic")))
.List<Cat>();
your comment about AnotherCat again implies that there is some way of discriminating between entities at the db level.
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