[Lazarus] OOP - where do you start?

[Marcos Douglas]

On Fri, Jun 26, 2015 at 9:47 AM, Michael Van Canneyt
<michael at freepascal.org> wrote:
>
>
> On Fri, 26 Jun 2015, Graeme Geldenhuys wrote:
>
>> Hi,
>>
>> Last night I was working on a relatively new project. This got me
>> thinking... How do others tackle such a task?
>>
>> So here is my question:
>>
>>  When faced with a new database related project, where do you start? Do
>> you first design the database schema, then build the BOM (Business
>> Objects) accordingly? Or, do you first design the BOM, then design the
>> database schema to fit.
>>
>> Personally, most of my project were started by first creating the
>> database schema. Don't ask me why, that is just what I did. Maybe it was
>> because many of the tools I use, can write much of the boiler plate code
>> for me, and they do that by querying a database structure. But I've been
>> thinking that with my next project, I'm going to start with the BOM
>> first, and see how it goes. I'm assuming the end result should be the
>> same, no matter which part I tackled first.
>>
>> What's your thoughts?
>
>
> I always start with the data. Almost all applications I ever wrote have
> databases.
> The data structure is in my experience always clear, simple. And thus I
> consider it a good foundation for the rest.
>
> Things start to get messy when you start thinking about functionality.
> So that comes next, and the business classes reflect functionality, and
> consequently more susceptible to change.
>
> Luckily the persistence layers I use are flexible enough to allow any
> mapping between data and business objects,
> so the above approach has always worked for me.
>
> I'm tempted to say that working the other way round is bound to lead to
> confusion.

Confusion... That depends if you work using a data-driven design or
behavior-driven design.

Marcos Douglas