#25 DOMAINS

[Dmitry Konnov]

What i would like to have in IO is some
support for simple Busines rules without coding.
Some kind of DOMAIN implenemtation like in FireBird.

It would be nice, in design time to create own eccential
types and be able to extend simple types.

For example:
Attribute shows gender of person. Male/Female

I would rather had CHAR(6) field in database with
check of value VALUE IN ("Male","Female")

I think this is possible to implement in IO.

procedure TClass.SetValue(const Value: string);

should have some CheckValue predefined macro
which does nothing by default.

but if corresponding version of CheckValue assigned
then it should check the input value.

the VALUE IN ("Male","Female")
should be possible assign in design time.

Maybe it need to use VCL streamed String properties,
to save 'VALUE IN ("Male","Female")' in design time,
but in run time parse the value and use the check rule.
Maybe some scripting engine here will help.

Dmitry