Thats a good point tom. In fact, null can be kind of like a special "state" - certainly with databases it is.
Keep the thoughts coming please. On 3/16/07, Tom Gonzalez <[EMAIL PROTECTED]> wrote:
We handle it as it can't be anything else but null cause null is returned when an access fails or some error occurs. This keeps it from falling into a valid evaluation and possibly a subtle bug going uncaught. Tom G ------------------------------ *From:* [EMAIL PROTECTED] [mailto: [EMAIL PROTECTED] *On Behalf Of *Mark Proctor *Sent:* Thursday, March 15, 2007 12:42 PM *To:* Rules Dev List *Subject:* Re: [rules-dev] need advice re null handling Its not about giving it up, its how we handle when those fields are null, do we treat it like a primitive and assume its 0, or do we say it can't be equal to anything else but null. In the following example neither y or z is defined, thus y is null and z is 0; int x = 0; Integer y; in z; x == y // is false; x == z // is true y == null // is true Mark Tom Gonzalez wrote: The flexibility provided by an Object is very valuable. We use Integer and String objects all over the place today in our facts with drools. I would hate to give it up. Tom G ------------------------------ *From:* [EMAIL PROTECTED] [ mailto:[EMAIL PROTECTED]<[EMAIL PROTECTED]>] *On Behalf Of *Mark Proctor *Sent:* Thursday, March 15, 2007 6:29 AM *To:* Rules Dev List *Subject:* Re: [rules-dev] need advice re null handling if bar is an integer it will be 0, if its an Integer it will be null. The Q is do we make Integer work like the primitive, or do we make it work like an Object. Mark Michael Neale wrote: http://jira.jboss.com/jira/browse/JBRULES-627 OK, this much is clear: Foo(field == null) can be true if field is null. but, what about Foo(field > 3), and field is null? should that be false? what about Foo(field != 3) - should that be true? in SQL, null will always result in a false condition, unless you explicitly use null. Thoughts? Michael. ------------------------------ _______________________________________________ rules-dev mailing list [EMAIL PROTECTED]://lists.jboss.org/mailman/listinfo/rules-dev ------------------------------ _______________________________________________ rules-dev mailing list [EMAIL PROTECTED]://lists.jboss.org/mailman/listinfo/rules-dev _______________________________________________ rules-dev mailing list [email protected] https://lists.jboss.org/mailman/listinfo/rules-dev
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