nhibernate query compositeid exception

Question

I am getting an error on what looks to be quite a simple QueryOver. The complication is that the select involves a CompositeId.

The error I am getting is:

System.InvalidOperationException: variable 'x' of type 'nha.cs.utility.mole.QueryParameters' refrenced from scope '', but it is not defined.

I am mapping a query that has many query parameters. The composite id is with the query and the query parameter name, shown below.

public class Query
{
    public virtual int id { get; protected set; }
    public virtual string name { get; set; }
    public virtual string query { get; set; }
    public virtual IList<QueryParameters> parameters { get; set; }
    public virtual IList<Application> applicationsUsedIn { get; set; }

    public Query()
    {
        this.parameters = new List<QueryParameters>();
        this.applicationsUsedIn = new List<Application>();
    }

    public virtual void AddParameter(QueryParameters qp)
    {
        qp.query = this;
        this.parameters.Add(qp);
    }
}

public class QueryParameters
{
    public virtual Query query { get; set; }
    public virtual string name { get; set; }
    public virtual string type { get; set; }
    public virtual int order { get; set; }

    public QueryParameters()
    {
    }

    public QueryParameters(Query qry, string nm)
    {
        this.query = qry;
        this.name = nm;
    }

    public override bool Equals(object obj)
    {
        if (obj == null)
            return false;
        var t = obj as QueryParameters;
        if (t == null)
            return false;
        if (query == t.query && name == t.name)
            return true;
        return false;
    }
    public override int GetHashCode()
    {
        return (query.id + "|" + name)).GetHashCode();
    }
}

    public QueryMap()
    {
        Table("dbo.Queries");
        Id(x => x.id);
        Map(x => x.name);
        Map(x => x.query);
        HasMany(x => x.parameters)
            .Cascade.All()
            ;
        HasManyToMany(x => x.applicationsUsedIn)
            .Table("dbo.ApplicationsQueries")
            .ParentKeyColumn("qryid")
            .ChildKeyColumn("appid")
            .Inverse()
            .LazyLoad();
    }

    public QueryParametersMap()
    {
        Table("dbo.QueryParameters");
        CompositeId()
            .KeyReference(x => x.query)
            .KeyProperty(x => x.name)
            ;
        References(x => x.query).Column("qryid").Not.Insert();
        Map(x => x.name);
        Map(x => x.order);
        Map(x => x.type);
    }

    public Query addParameterToQuery(Query qry, string paramname, string paramtype, int paramorder)
    {
        if (null != qry)
        {
            string qryname = qry.name;
            string qrystr = qry.query;

            using (ISessionFactory isf = getSessionFactory())
            {
                using (var sess = isf.OpenSession())
                {
                    using (var tran = sess.Transaction)
                    {
                        try
                        {
                            tran.Begin();

                            var critqry = sess.CreateCriteria<Query>()
                                .Add(Restrictions.Eq("name", qryname));

                            Query qryd = (Query)critqry.UniqueResult();

                            if (null == qryd)
                            {
                                qryd = new Query();
                                qryd.name = qryname;
                                qryd.query = qrystr;
                                sess.Save(qryd);

                                Console.Out.WriteLine("Query was null, added new query with name '" + qryname + "'");
                            }
                            else
                            {
                                Console.Out.WriteLine("Query was not null, has name '" + qryname + "'");
                            }

                            //EXCEPTION THROWN ON THIS LINE BELOW
                            var cp = sess.QueryOver<QueryParameters>()
                                .Select(x => x.query == qryd, x => x.name == paramname);

                            QueryParameters qryparam = cp.List().First<QueryParameters>();

                        }
                        catch (Exception ex)
                        {
                            tran.Rollback();
                            lws.logMessage(AppName, "addParameterToQuery", ex.ToString(), MessageType.Info, MessageLevel.Error);
                            Console.Out.WriteLine(ex.ToString());
                        }
                    }
                }
            }
        }

        return (null);
    }

Any thoughts or pointers would be greatly appreciated.

Thanks,

Bruce.

UPDATED CODE

public class QueryMap : ClassMap<Query>
{
    public QueryMap()
    {
        Table("dbo.Queries");
        Id(x => x.id);
        Map(x => x.name);
        Map(x => x.query);
        HasMany(x => x.parameters)
            .Cascade.All()
            .KeyColumn("qryid");
        HasManyToMany(x => x.applicationsUsedIn)
            .Table("dbo.ApplicationsQueries")
            .ParentKeyColumn("qryid")
            .ChildKeyColumn("appid")
            .Inverse()
            .LazyLoad();
    }
}

public class QueryParametersMap : ClassMap<QueryParameters>
{
    public QueryParametersMap()
    {
        Table("dbo.QueryParameters");
        Id(x => x.id);
        References(x => x.query).Column("qryid").Not.Insert();
        Map(x => x.name);
        Map(x => x.type);
        Map(x => x.order).Column("ordr");
    }
}

    var cp = sess.QueryOver<QueryParameters>()
        .Where(x => x.query.id == qryd.id)
        .And(x => x.name == paramname);

Answer 1

One issue is usage of the .Select() as a filtering section. When using QueryOver we have to use .Where() instead:

var cp = sess.QueryOver<QueryParameters>()
    //.Select(x => x.query == qryd, x => x.name == paramname)
    .Where(x => x.query.Id == qryd.ID)
    .And(x => x.name == paramname)
    .List<QueryParameters>();

See 16.2. Simple Expressions . The .Select() could narrow the resultset, because its definition will be used for a SELECT clause creation: 16.6. Projections

To include more related objects/entities into the query we can use 16.4. Associations (ie JOIN related tables)

NOTE: Bruce, if possible, I would try to re-think about the domain model. The many-to-many and composite-id are signs of something beeing over-complex (if not over-complicated) . I tried many time before descourage people from using the exotic mapping... it is there for legacy purposes. Maybe check this section: 24. Best Practices