This version of Rel is a maintenance release.
The following bugs have been fixed:
1) Given a relation with a relation-valued attribute having cardinality 0, e.g.:
EXTEND S {S#} ADD (RELATION {TUPLE {S# S#}} COMPOSE SP AS SP_result)
Ungrouping this relation caused a Java exception, e.g.:
EXTEND S {S#} ADD (RELATION {TUPLE {S# S#}} COMPOSE SP AS SP_result)
UNGROUP (SP_result)
This has been corrected.
2) A bug in RENAME made it possible to create duplicate attribute names. E.g.:
sys.Catalog RENAME (Definition AS Name)
This has been corrected.
3) Due to a bug in the mechanisms that compare values of user-defined types when
used in relvar attributes, certain expressions like S JOIN SP JOIN P returned
bogus results. This has been corrected.
4) GROUP with multiple AS clauses, or performing GROUP on a relation
with relation-valued attributes, e.g...
(sys.Catalog GROUP ({isVirtual, Name} as Blah, {Owner} as Blah2))
...threw a Java exception. This has been corrected.
5) DBrowser incorrectly displayed RATIONAL values of NaN, -Infinity and Infinity.
This has been corrected.
For more information, or to download Rel, see http://dbappbuilder.sourceforge.net/Rel.html