Re: OOP/OOD Philosophy

frebe wrote: 
I asked you " Why would it be suicide to have a coupling between the
GUI and  database schema?"

You gave me an example that did not involve any database access at all.
 Can you please give me an example of the bad thing with coupling
between the GUI and database schema?

If your example would have any thing to do with a database, maxItem and
totalAmt would be calculated this way:
select max(item) from product
select sum(amount) from product

Fredrik Bertilsson
http://butler.sourceforge.net


Well, here's one and it is a very sad tale. I once worked with a team that embedded database calls throughout their application. They were all over the place. The vendor raised the licensing rate and they simply could not make money with the product. The team wished that they could break the dependencies on the vendor but the calls were too pervasive. The whole thing ended up with a very expensive rewrite which, by the way, had a good amount of separation between the db and the rest of the app. They learned a very expensive lesson about dependencies.


Michael Feathers
author, Working Effectively with Legacy Code (Prentice Hall 2005)
www.objectmentor.com

.

Relevant Pages

  • Re: Queries and OO
    ... >>Isn't queries something you may need even if you don't use a database? ... > language other than the programming language. ... Regular expression matching, XPATH queries, ...these things ... To manage or to obfusicate :-) You can also create a lot of dependencies ...
    (comp.object)
  • Re: DPS Initial Ideas
    ... of "The FreeBSD package system is broken and needs to be fundamentally ... Rewriting it to use SQLite is a fundamental change. ... running a perl script to connect to a Berkeley database. ... It may be that borrowing from Debian the idea of "abstract" dependencies ...
    (freebsd-hackers)
  • SMF services stoppping order
    ... I'm totally confused about order in which SMF service are stopped (or ... web server (depends on working database) ... multi-user-server milestone (depends on web server) ... about propability of such dependencies between services' processes. ...
    (comp.sys.sun.admin)
  • SMF services stoppping order
    ... I'm totally confused about order in which SMF service are stopped (or ... web server (depends on working database) ... multi-user-server milestone (depends on web server) ... about propability of such dependencies between services' processes. ...
    (comp.unix.solaris)
  • Re: Principle of Orthogonal Design
    ... as is usual in normalization theory. ... A schema is said to be in HNF if all database dependencies follow ... and relation constraints) and the inclusion dependencies. ...
    (comp.databases.theory)
Loading