how to make db class?(newbie)

[Alexey Alexapolsky]

When I edit newapp-schema.xml
and add there a definition of new table 
and run ANT in the same dir -  it creates no classes
and also deletes my table from  schme file.
When I run ant from the /build dir , it builds on source file
and does nothing more. May be I don't understand how to create
db clasees for my table ?
 
Tkanks,
Alex