Re: Database I/O Modernization

from: "D*B" <dieter.bender@xxxxxxxxxxxx>
subject: Re: Database I/O Modernization

@open source: the link points to an example, tied to a special file module
cusmstf. You would need an instance of this for every file. If someone
would
provide a programm, generating such modules, this might be called open
source.
@interface: having one entry point with an parameter Action is not best
practice of modularisation. Why not export insertCusmst, updateCusmst,
SetllCusmst... with only those parms, which are needed. This would be more
handy to use too, replacing the RLA Opcodes in the current programms with
very similar calls. (BTW this should be done by a generic programm,
generating the needed code.
@modernisation: such a programm could be a first step in the right
direction, it decouples business logic from database IO, but there are
follow ons needed:
- changing the table layout of the underlaying table, the change has to be
made for the I/O module only. keeping the current version adding a new!!!
now recompile orgies of business layer
- replacing the RLA in the I/O modules, where needed, would enable the
possibility of instead triggers, giving new possibilities for database
redesign steps.
- replacing rla by sql, multiple of these I/O modules could share same
logic
(diffrent order only)
- replacing rla by SQL, the modules could be enhanced by an exported
subprocedure setOrderByCusmst (BTW: I'm using this as exercise in one of my
workshops)
- replacing rla by SQL the setllCusmst could be enhanced by the possibility
to use non key values for setll
- replacing rla by SQL the module could be enhanced by an exported
procedure
filterCusmst (setting a where clause)
@joining files: this should be done in most cases in the view layer anyway.

This might be a starting point, but at the moment, it's only making a
diffrence in programms where I replace the RLA by calls to such an I/O
module. As long as the implementation of the module simply reflects one to
one the same RLA operations nothing has really changed.

D*B