[RuleML-all] Re: Need help to define to understand RuleML

Tue Aug 7 17:14:11 ADT 2007

Hi Baher,

Some reasons for embedding a (business) rule engine in Java
can be extracted from "The Principles of Rule Independence"
<http://www.businessrulesgroup.org/brmanifesto.htm>.

Prova and OO jDREW allow you to run subsets of RuleML 0.91
<http://www.ruleml.org/0.91> as part of an enclosing Java
environment, with the advantage that RuleML rules are kept
in separate, easier-to-maintain XML rulebases.

Can you show us some of your (simpler :-) rules in Java, so
we have a challenge to do them more declaratively in RuleML?

Prova also supports the evolving Reaction RuleML, for which
OO jDREW may come up with extensions, too. While findall is
not yet in RuleML, this and other aggregation operators are
certainly quite important for future releases. In bottom-up
mode, OO jDREW does a kind of findall, but this is not yet
integrated into the top-down mode.

Your original example could of course also be implemented in
other ways. If your data table is represented as a list of
pair lists <http://www.ruleml.org/0.91/glossary/#gloss-Plex>
(which could also be the result of a findall call), then an
integrity rule could alert users of duplicate pairs in the
outer list.

Best,
Harold 

________________________________

From: ruleml-all-bounces at ruleml.org
[mailto:ruleml-all-bounces at ruleml.org] On Behalf Of Baher Omar
Sent: Friday, August 03, 2007 1:01 AM
To: ruleml-all at ruleml.org
Subject: [RuleML-all] Re: Need help to define to understand RuleML

Thanks Adrian for your help..

I read more about Prova and it's a very powerful engine. 
However, I don't know why I should choose Prova over Java language as my
language to write my rules!! Java could provide most of the capabilities
that Prova supports (with a little more development for sure).

In the matter of fact, all my rules today are implemented in Java.. and
I want to move away from that by selecting a simple xml based rule
definitions and a supported engine..

jDREW seems to be simple enough for my needs, but does jDREW support
Reaction RuleML and maybe generic functions like (findall)?!

Thanks,
-b

On 8/1/07, Adrian Paschke <paschke at in.tum.de> wrote: 

	Hi Baher,

	A quick answer, since I m currently travelling.

	You may take a look at the Prova documentation: 

	http://www.prova.ws/etc/provauserguide_2_0.pdf

	Chapter 4 describes several built-ins. Prova is an open-source
engine
	capable of executing Reaction RuleML and in particular supports 
	interchange of event messages.

	We will soon release the next version of Reaction RuleML:

	http://ibis.in.tum.de/research/ReactionRuleML/0.2/ 

	Reaction RuleML supports messages and messaging reaction rules
(rules
	which send and receive messages), e.g.:

http://ibis.in.tum.de/research/ReactionRuleML/0.2/examples/message.rrml
<http://ibis.in.tum.de/research/ReactionRuleML/0.2/examples/message.rrml
> 

http://ibis.in.tum.de/research/ReactionRuleML/0.2/examples/MessagingRule
.rrml

	I will send you are more detailed answer when I m back. 

	BTW the deadline for demo submissions to RuleML-2007 has been
extended:

	http://2007.ruleml.org/

	This could be interesting for you to submit a demo to the
Challenge and 
	meet the business rules and rules standardization community

	Best,

	Adrian
	________________________________________
	Von: ruleml-all-bounces at ruleml.org 
	[mailto:ruleml-all-bounces at ruleml.org] Im Auftrag von Baher Omar
	Gesendet: Mittwoch, 1. August 2007 13:44
	An: ruleml-all at ruleml.org 
	Betreff: [RuleML-all] Re: Need help to define to understand
RuleML

	Thanks Adrian,

	Your answers will certainly help to put me on on the right
track!

	I don't think my table has a single key, it might be an
aggregate key.. 
	Nevertheless, I like the idea of findall function.. I basically
need a
	search mechanism in my data set..
	Is there a place where I can find more information about
well-known
	functions?

	I was reading on the Reaction RuleML, and I thought that was the
right 
	RuleML variation for my application.. (Hence I need message
based actions).
	However, I had difficulty finding the correct reading materials
to learn
	more about Reaction RuleML, so I decided to go back to the basic
RuleML 
	and exercise more of it..
	Is there any open-source rule engine for Reaction RuleML?!

	To answer your last question, I think my system is more of a
	verification system. It should have business rules and a
database. I 
	want to use RuleML to verify the business rules aganist a data
data
	before committing data to the database.. Therefore, I need to
use
	message based actions to report errors to the end-user.
	Ultimately, I want to share my business rule with other
applications and 
	maybe other parties..

	Thanks again,
	-b

	On 8/1/07, Adrian Paschke <paschke at in.tum.de> wrote:
	Hi Baher,

	The solution depends on how the table data is represented. 

	Assume each row (data set) in the table has a unique id (like a
primary
	key) then the fact representation could be tableName(ID,X,Y),
e.g.

	pair(1,x1,y1).
	pair(2,x2,y2).
	&

	A backward-reasoning derivation rule to detect the error could
then be 
	as follows:

	error(X1,Y2) :- pair(ID1, X1,Y1), pair(ID2, X2,Y2), ID1!= ID2,
X1=X2,
	Y1=Y2.

	The RuleML serialization is:

	<Implies>
	<head>
	<Atom><Rel>error</Rel></Atom> 
	<Var>X1</Var>
	<Var>X2</Var>
	</head>
	<body>
	<And>
	<Atom>
	<Rel>pair</Rel>
	<Var>ID1</Var>
	<Var>X1</Var>
	<Var>Y1</Var> 
	</Atom>
	<Atom>
	<Rel>pair</Rel>
	<Var>ID2</Var>
	<Var>X2</Var>
	<Var>Y2</Var>
	</Atom>
	<Not>
	<Equals>
	<Var>ID1</Var><Var>ID2</Var> 
	</Equals>
	</Not>
	<Equals>
	<Var>X1</Var>
	<Var>X2</Var>
	</Equals>
	<Equals>
	<Var>Y1</Var>
	<Var>Y2</Var>
	</Equals> 
	</body>
	<Implies>

	If you don t have an ID, then you might use a function like
	findall(pair(X,Y),pair(X,Y),List) which aggregates all pairs in
a list
	which you might traverse and look for repeated members. However,
your 
	execution environment needs to support findall (many derivation
rule
	engines support it, e.g. Prova).

	You might also use assert and retract update primitives (if
supported)
	to implement a global solution. Reaction RuleML 
	( http://ibis.in.tum.de/research/ReactionRuleML) is supporting
derivation
	rules with update primitives.

	Or is your execution environment a production rule system? XML 
	serialization of production rules are also addressed by Reaction
RuleML.

	Best,

	Adrian

	________________________________________
	Von: ruleml-all-bounces at ruleml.org
<mailto:ruleml-all-bounces at ruleml.org> 
	[mailto: ruleml-all-bounces at ruleml.org] Im Auftrag von Baher
Omar
	Gesendet: Mittwoch, 1. August 2007 06:30
	An: ruleml-all at ruleml.org 
	Betreff: [RuleML-all] Need help to define to understand RuleML

	I'm new to RuleML and I have difficultly coming up with an
equivalent
	RuleML for the following rule:

	"if X is repeated in a sequence of variables then that's an
error" 

	Suppose I have the following table data:

	X Y
	----------
	x1 y1
	x2 y2
	x3 y2
	x1 y1
	x2 y3

	x1 occurs twice under y1, that's the violation I'm looking for..

	How can I describe this rule in RuleML?! 

	Thanks,
	-b