Re: [rules-users] Guvnor, database and rule language
First off, the query should be:
from Customers where TN = :tn and balance > 0
And that would be only if you mapped the tn property to the name "TN". HQL
queries are case sensitive when it comes to property names:
http://www.hibernate.org/hib_docs/v3/reference/en-US/html_single/#queryhq...
Second, I don't know if that whole "hibernateSession.createQuery" expression
would compile in a DRL file. Have you tried it? Anyone?
Finally, this rule will fire for every Customer in working memory and look up a matching
Customer in the database. Seems a bit inneficient, especially if you have many rules of
this type. Would it be possible to load the Customer from the database and just insert it
into working memory with it's "balance" property already set? That would
be far simpler. Then the rule would be:
global org.hibernate.Session hibernateSession;
when
cust1:Customer(balance > 0)
then
cust1.setIsAllowed(false);
hibernateSession.save(cust1);
end
(Ignoring the transaction management, here.)
You could even skip the save() on the hibernate session in the rule action. You could
keep the hibernate session open and save the Customers when you've completed all
changes.
--- On Tue, 3/31/09, Anu@work <anupama.vaid(a)bluecasa.com> wrote:
From: Anu@work <anupama.vaid(a)bluecasa.com>
Subject: [rules-users] Guvnor, database and rule language
To: rules-users(a)lists.jboss.org
Date: Tuesday, March 31, 2009, 3:04 PM
I am trying to use drools to evaluate the following rule:
Given a telephone number, if the telephone number already
exists in database
and has a balance > 0, set isAllowed = false. I cannot
figure out how to
write the rule.
This is my object
public class Customer implements Serializable {
private static final long serialVersionUID = 1L;
private String tn;
private Double balance;
private Boolean isAllowed;
// getters/ setters
}
Can anyone help me with the rule below? The TN is set in
the input fact. Is
the query below correct? It looks incorrect.
global org.hibernate.Session hibernateSession;
when
cust1:Customer()
cust2:Customer() from
hibernateSession.createQuery("Select * from
Customers Where TN = :tn and balance >
0).setProperties({"tn":cust1.getTn()})list()
then
cust1.setIsAllowed(false);
--
View this message in context:
http://www.nabble.com/Guvnor%2C-database-and-rule-language-tp22810206p228...
Sent from the drools - user mailing list archive at
Nabble.com.
_______________________________________________
rules-users mailing list
rules-users(a)lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users