Head First Design Patterns
Head First Software Development (more about the business processes involved in a software project)
Head First Object Oriented Analysis and Design

all published by O'Reilly.
There are tons more books out there, but these are fun to read as well as informative and instructive
Sun also has a good course on OO design and engineering, course number OO-226. 5 days instructor led training, well worth the pricetag (a good instructor can teach you a LOT in a few days).


And some advise when you're trying to divide up the system into "layers": don't overdo it.
Don't go "pattern crazy" and start applying patterns everywhere. It makes the design unwieldy, the resulting application sluggish, unresponsive, overly complex, and hard to maintain.

@ jwentig

yes i learned it the hard way. that is why i said that i only now appreciate salem's words.

my programming is reasonably competent but i messed up the design. luckily my boss is very understanding. and i dont know how much it helps that he is already a programmer or two short and dont want to fire the only one he has!

thing is i think that layered design will have to wait until i have learned design. there i kind of suck. with small projects it was fine but with my current one, rather big, i got the design all wrong.

layered architecture consists of 3 different layers in the project.

presentation layer (PL)- cinsisting of all the ui and properties (data members) no methods!!

business layer (BL)- all the business logic in one. methods only.

data layer (DL)- all database logic.

a forth wrapper can be added that has universal functions for database access which cawn also be used in different projects. between dawta layer and database provide

PL would have reference of BL to pass on the values to it. BL would have of DL. and DL would have of the wrapper. but not vice versa.

in a way its one way.

returning is done by return statement.

hope it helps you.