CODEWITHSUNDEEP
nhibernatemappingbooleancompatibility
Terenzio Berni
Terenzio Berni

Reputation: 495

NHibernate hbm mapping collection whith where condition on boolean property

I have an entity A with a bool property (lets call it BProp). In a second entity there is a bag mapping of A elements with a where condition on BProp like this:

<bag name="MyBag" cascade="all-delete-orphan" inverse="false" where="BProp = 1">
    <key column="Structure_Id" />
    <one-to-many entity-name="A" />
</bag>

The problem is tha BProp = 1 works with SqlServer and Oracle but breaks PostgreSQL which needs a condition like

where="BProp = true"

Is there a clever way to create a single hbm.xml mapping for all the three db I have to suppport?

Upvotes: 2

Views: 1238

Answers (1)

jbl
jbl

Reputation: 15413

As the query substition does not seem to be a usable solution in this filter case, you may go for query interceptor (here a quite rough implementation) :

public class BooleanInterceptor : EmptyInterceptor, IInterceptor
{
    public string TrueToken { get; set; }
    public string FalseToken { get; set; }   

    NHibernate.SqlCommand.SqlString IInterceptor.OnPrepareStatement(NHibernate.SqlCommand.SqlString sql)
    {
        return sql.Replace("{TrueToken}", TrueToken).Replace("{FalseToken}", FalseToken);
    }
}

Your mapping would then be where="BProp = {TrueToken}"

It would be used like this 

var interceptor = new BooleanInterceptor ();
using (var session = sessionFactory.OpenSession(interceptor))
{
    interceptor.FalseToken = "0";  // this replacement value should be taken from a config file
    interceptor.TrueToken = "1";  // see above

    // your code here

    session.Close();
}

I bet there are way better solutions, but I hope this will help anyway

-------------------------- previous answer

I use to insert query substitutions in my NHibernate configuration, like this

var cfg = new Configuration();
cfg.Properties.Add("dialect", "NHibernate.Dialect.MsSql2005Dialect");
.
cfg.Properties.Add("query.substitutions", "true 1, false 0");
.

I guess you could have your xml mapping with where="BProp = true" and just insert the cfg property for query.substitions depending if the dialect is MsSql / Oracle or PosgresSQL

Upvotes: 1

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