The Tools Guide is unclear about what you can expect dblook to do for you. The top level section on dblook makes the modest claim that you can use dblook to view the schema of a database--no claim is made that the view is consistent or usable. However, the later section "Generating the DDL for a database" suggests that you can recreate your database using the script produced by dblook. It would not be unreasonable for a user to try to do this.
However, the following problems mean that you can't rely on the script produced by dblook:
1) No attempt is made to sort objects according to their dependencies. For instance, foreign key tables might be declared before the primary key tables which they reference.
2) No attempt is made to interleave object creation with privilege and role grants and there is no support for setting the session to the correct user id and role needed to make the DDL succeed and register the correct dependencies.
3) Bugs related to function resolution (see
DERBY-3944, DERBY-3955, and DERBY-3953) mean that TABLE and VIEW DDL may fail.