Re: DAO Semantics WAS: RE: [CFCDev] table DAO

[Joe Ferraro]

I'm confused about your comments here Sean. Where can I find out more 
information about a data gateway? This confusion stems from the book 
Core J2EE Pattens which I've been using to aid me in my design 
strategies. On the bottom of page 466 it reads: "Furthermore, a Data 
Access Object also provides other methods to find multiple results 
(finder methods) to return a list or other collection objects)." From 
that I was under the assumption that you could add more than the crud 
methods to the DAO to aid in finding sets of data. Is this an incorrect 
assumption and or is there one "right" way to do this?

Thanks a lot!
Joe Ferraro
Web Application Developer
Ken Cook Co.
Sean Corfield wrote:
On Mon, 15 Nov 2004 14:06:35 -0600, Dawson, Michael <[EMAIL PROTECTED]> wrote:
 

I'm using a DAO that, in turn, manages a database table.  At this point
in time, I only need to pull two of the, let's say, five columns.
   

A DAO deals with data from a single row so usually it brings back all
columns (and puts them into a business object or transfer object).
DAOs typically only have CRUD methods. DAOs typically return nothing
(if they update an object that is passed in) or they may return a
populated object (e.g., for create()).
Your examples bring back query objects so I think you're really
talking about a data gateway instead in which case its methods will
return queries with whatever data your application needs.
 

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