[Lazarus] OOP - where do you start?

Marcos Douglas md at delfire.net
Fri Jun 26 16:31:04 CEST 2015

On Fri, Jun 26, 2015 at 10:04 AM, Donald Ziesig <donald at ziesig.org> wrote:
> Hi Graeme,
> As mentioned in one of the earlier replies, it really depends on the
> complexity of the application and the state of the Business Rules.
> If I have a detailed definition of the Business Rules (a really rare
> occurrence), I will start with the BOM and UI.  I sometimes build in some
> data fixtures without ever touching the database till I am reasonably sure
> that the BOM/UI and Fixtures describe the Business Rules.  Then I will start
> moving the fixtures into the schema one or two at-a-time with constant
> testing.
> When I don't have a detailed definition of the rules (the usual case), I
> start with top-level rules and one or two top-level tables, their associated
> BOMs and UIs.  After each set of BOM/UI/Tables I sit down with the customer
> and demonstrate what I have so far.  We then agree on any changes that must
> be made and we iterate till that set of requirements are being satisfied.
> Often we also agree on what part of the rules should be implemented next.
> Most of the time, the customer "waves her hands" to describe what the
> program must do, so it is up to me to actually start developing the Business
> Rules.  When that happens, the second approach helps by reducing the amount
> of throw-away code required till the customer gives his/her approval.
> (Especially when the customers are my own daughter and grand-daughter).
> My most recent project was a translation of a pre-Windows c++ program with a
> CLI for the user interface and no database into Lazarus with sqlite3.  Since
> the rules were well established, just implemented with very old technology,
> I used the first approach and it worked very well.  I had almost the entire
> program working in test mode before I had to touch the database for
> production.
> Hope this helps.
> Don Ziesig, ROP (Really OLD Programmer);-)


Marcos Douglas

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