Playing around with Db/2 Command Line and ended up with an interesting insight.
Here is the query :-
db2 select count(*) from Dimension.Date
SQL0204N "DIMENSION.DATE" is an undefined name. SQLSTATE=42704
Escape Object Name
Please quote object names by enclosing the schema and table in double quotes.
And, escape the double quotes with a back slash.
db2 select count(*) from \"Dimension\".\"Date\"