Note that I am placing this post here for future reference as this is a FAQ that I do not see addressed in the current NORMA documentation stack.
To change the default data types specific to your RDBMS you need to modify the XLST Stylesheet that is used during the generation process. At the time of this writing, that can be found in the following location (WinXP): "C:\Program Files\Common Files\Neumont\DIL\Transforms".
Pick the Stylesheet of interestes, e.g., DDILtoOracle.xslt, and edit accordingly. For exmaple, if you want all BOOLEAN types in Oracles to render as "CHAR(1)", you would navigate to the entry for the BOOLEAN type and make the corresponding change from the default of "NCAHR(1)".
-- Ronald M White