IN + empty collection throws exception

roniburd · **Posted:** Tue Dec 27, 2005 7:39 pm

The following HQL expression fails with a "Not all named parameters have been set" exception.

The query is like this

Code:

from UploadCustodias upload where upload.mFechaDatos = :fecha and upload.mCustodia in (:custodias)

and later:

Quote:

Return this.CreateQuery(hql).SetDateTime("fecha", fecha).SetParameterList("custodias", custodias).List()

When custodias == null I get the exception.

emmanuel · **Posted:** Wed Dec 28, 2005 5:25 am

what's the point of doing a query and going to the DB if the list is null or empty.

sergey · **Posted:** Wed Dec 28, 2005 9:55 am

A null list won't work. An empty list should, but you should then better specify the IType explicitly (use 3-parameter version of SetParameterList).

emmanuel · **Posted:** Wed Dec 28, 2005 11:03 am

Some DBs do not support

Code:

in ( )

in SQL, though

sergey · **Posted:** Wed Dec 28, 2005 11:52 am

I added a workaround for this to NHibernate some time ago.

Nels_P_Olsen · **Posted:** Wed Dec 28, 2005 1:52 pm

We set up collections (all properties actually) with field access rather than property access. This allows the property getters to lazy initialize collections to empty ArrayLists, and null strings to empty strings, so that there are no nasty surprises when writing application-level code. Your code shouldn't ever end up with or have to deal with a null collection reference.

TheShark · **Joined:** Thu Aug 25, 2005 3:35 am **Posts:** 160

Nels_P_Olsen wrote:

We set up collections (all properties actually) with field access rather than property access. This allows the property getters to lazy initialize collections to empty ArrayLists, and null strings to empty strings, so that there are no nasty surprises when writing application-level code. Your code shouldn't ever end up with or have to deal with a null collection reference.

So you write something like this?
get { if(_field==null) _field = new Arraylist(); return _field; }

roniburd · **Posted:** Thu Dec 29, 2005 4:51 pm

I've managed to solved the problem with 2 queries but was wondering what was the workaround Sergey was referring to.

Nels_P_Olsen · **Posted:** Fri Dec 30, 2005 12:51 am

TheShark wrote:

Quote:

So you write something like this?
get { if(_field==null) _field = new Arraylist(); return _field; }

Exactly.

sergey · **Posted:** Fri Dec 30, 2005 6:59 am

roniburd wrote:

I've managed to solved the problem with 2 queries but was wondering what was the workaround Sergey was referring to.

Hibernate 2.1 generates SQL like "in ()" for an InExpression with an empty list. Almost no databases support empty list after in, so NHibernate will instead generate "1=0" in this case.