[REBOL] Re: Data validation dialect
From: gerardcote:g:mail at: 23-Dec-2009 22:14
Hi Graham,
This is what I will begin with but my true goal is to have both an
implementation and a dialect for describing what the data validation
rules specs are, be it localized in the app itself or in an external
shared data object or centralized dictionary. Kind of minimalist
general business rule encoding - like is done by databases systems and
centralized data-centric objects in a true multi-tier app - eventually
I'd like to have such a system running ... since I gradually want to
move the business rules from the presentation layer (GUI) to a common
data layer, which is somewaht easier to share across a distributed
app, via services, for example.
For the moment, I'm trying to figure out most of the common ways in
use that describe form (and field) data specs and validation rules and
what is better done at the UI level. Sometimes but not always, this
kind of validation is driven by the data type and the domain of values
each type permits.
So I want to collect some of those ways that are in actual use, just
to see if there is some general logic that can be applied through my
own "data validation definition dialect" design.
Here is my first summary : (sure there are others and would be glad it
anoybody would enrich/correct this first draft)
(My only past experience in this domain comes from the design of
VB input forms, thus
validating at the field and at the form levels. Everything else
comes from recent readings.
So many misconceptions/missing info are more than probable).
At the field level we generally find those relevant attributes,
independently of the GUI system, I think :
----------------------------------------------------------------------------------------------------------------------------------------------------------
- Mandatory/optional
- Protected/writable
- Visible/hidden
- Size, position, color, etc...
- Behavior (local event management and simple validation rules - most
related to datatype,
i.e. Numeric! - discrete or continuous : min.
max, interval(s), inclusion or exclusion related boundary conditions
expressed by means of functions, etc...;
String! : pattern recognition, uppercase,
phone number, valid date, ...)
At the form level we have to take into account for :
------------------------------------------------------------------------
- Behavior (Global event management and dependencies between some or
all of the fields - expressed by more elaborate validation/derivation
rules)
Then there are also what are called the other more general business
rules - generally taken into acount at the object/database level
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
- Behavior/dependencies related to the business way of doing things (policies)
Just asked myself about what "formal or natural - dialect" language
could be used for defining the specs of these validation/business
rules AND WHERE TO PUT /when to use THEM ?
====================================================================================================================================
Began some research and found many alternatives already in use :
1- saw an article about the OCL part of UML that is used playing this
role for objects classes constraints (wikipedia)
2- saw in one of my old books a reference to BNF stating that by 1984
it was the formal tool to be used for string pattern recognition (Here
we have parse coupled with PEGs)
3- OASIS ia another formal description language used as the basis for
the OlivaNova OO-Method and the Just-UI
(See URLs : www.care-t.com/index.asp
www.ercim.org/publication/Ercim_News/enw57/pastor.html
www.dsic.upv.es/~einsfran/papers/06-CAISE97.PDF
portal.acm.org/citation.cfm?id=964442.964522
www.dsic.upv.es/grupos/oom/oasis.html - this last one the OSAIS
3.0 spec is available in Spanish only)
4- Finally in the prolific Java/Ruby World there are descriptive
testing tools (Fit, JBehave and RSpec) that are more of the By example
kind -
They describe the same thing the xUnit family members are able to
test but using a behavior related vocabulary
The refs about the tools related to BDD from Dan North and David
Chelimsky -
(URL dannorth.net/introducing-bdd)
See also Agiledox/TestDox tools
(URL agiledox.sourceforge.net/)
5- Then another view desserves a good mention about describing and
implementing business rules in REBOL itself -
(URL: computer-programming-languages.suite101.com/article.cfm/how_to_createa_rebol_dialect#ixzz0KnhL2yyi&C)
Why didn't I think about it before ? probably because I want to get a
descriptive approach and I wil have to create some dialect to do so.
6 Also found this about the new VB 9.0 Query mode - Will try to get my
hands for creating a similar one for REBOL when ready to do so
(URL : tinyurl.com/z8z82)
