Question

I am having some troubles crafting the HQL for a given nHibernate mapping file (nHibernate 1.2). This SQL Fiddle example shows the table structures and the results I’m wanting. Basically, I’ll pass in a Jurisdiction and I want all Titles with no jurisdiction or that specific jurisdiction. The current process pulls everything back and filters in code; I’m working to improve this so it filters at the SQL level.

Mapping file looks very similar to this.

<?xml version="1.0" encoding="utf-8" ?>
    <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2"
        assembly="MyApp.Business"
        namespace="Ap.Bus.Entity"
        default-access="field.camelcase-underscore"
        default-cascade="save-update" >

        <class name="Titles" table="dbo.Titles"  mutable="true" lazy="true">
            <!--Primary Key-->
            <id column="TitleID" name="Id" unsaved-value="0">
                <generator class="identity">
                </generator>
            </id>

        <property column="TITLE" name="Title"/>
        <property column="Enabled" name="Enabled" />

        <bag name="Jurisdictions" table="dbo.Jurisdictions" lazy="false" cascade="none">
            <key column="TitleID" />
            <many-to-many class="Ap.Shared.Jurisdiction, Ap.Shared" column="JurisdictionID"/>
        </bag>
</class>

I’ve tried so many different HQLs and I could never get it to work when I started joining to the Jurisdictions. It was working when only returning enabled Titles without the join.

So, how can I write the HQL to accomplish this?

Answer 1

select t
from Title t left outer join t.Jurisdictions as j
where j is null or j = :someJurisdiction

Possibly you should add “.JurisdictionID” to the last two “j” above.