Hi Frank,*,
I have made some tracing with hsqldb, so their are some strange things:

if I select a table in the DB-Explorer, OOo does first a:
select <ColumnName> from <Tablename> where 0=1 , and this for every Column
and than for every row of the resultset a:
SELECT * FROM "OOTable1" WHERE "OOTable1"."OOID" = 9

where 9 is only a single primaryKey. For me it seems that OOo builds the
resultsets by iterate thru this by singele sql-statements. 
If I go with basic to the db, all works fine.

BTW:
If anybody is looking as this, perhaps someone can point me to the steps what
OOo does by clicking on a table in the db-explorer