The Rel Forum

It's a bug in the mechanism that's supposed to generate an error message for MAX, MIN, UNION, D_UNION, and INTERSECT when performed on relations of cardinality zero. Instead of "ERROR: null" or an internal error, it's supposed to print: max (relation {x integer} {}, x) ERROR: Result of MAX...

How about sharing the code using a Mercurial (http://www.selenic.com/mercurial/wiki/) so that anyone (like me :wink:) can play with it, and if you like what I do, I can easily contribute it back to you? I could help only with simple stuff since I do not know much of the codebase, and sometimes my d...

How about a subversion host like Google Code? Maybe this has already been set up somewhere? I'm currently running an SVN repository on one of my Internet-accessible servers, which I open up to developers on an as-needed basis. I am considering using a public repository but in the past have been les...

As simplistic answer -- offered to spur further discussion rather than provide a definitive solution -- is that there is nothing, to my mind, that precludes providing "conventional" object-oriented constructs like classes, objects, inheritance and polymorphism strictly as a facility for or...

Tutorial D (and, hence, Rel ) define OPERATORs, which behave like procedures and functions in other imperative programming languages. For example, one could define a simple procedure as follows: OPERATOR blah (x INTEGER, y INTEGER); BEGIN; WRITELN "blah"; WRITELN x + y; END; END OPERATOR; ...

There's a "Rel Examples" section on this forum. I'll add some more examples as time permits, and although "sucks hairy bottom" is not quite the phrase I would use to describe SQL, I appreciate your point.

I change the point size to 24 for lecture-room demos, but next time I start up Dbrowser I have to do Tools/Options/Save to get the selected font to show in the lower pane (even though the menu does show the point size to have been remembered). I'll fix this in the next update. I note that changing ...

I've fixed this; it'll be corrected in the next update.

Oops. That's supposed to produce a user-friendly error message. It will be fixed in the next update.

This version of Rel fixes some bugs and provides several enhancements. First, the fixes: - In some cases, an expression that used the result of one WHERE operator as input to another WHERE operator would generate bogus results or throw an exception. This has been corrected. - JOINing relations with ...

Oddly, this bug appears to be related to the "Complex rel exp causes exception" bug described at http://shark.armchair.mb.ca/~dave/relforum/viewtopic.php?f=2&t=104. I've fixed the other bugs noted on September 26th and on October 6th, but these two are proving difficult. Both seem to ...

Oddly, this bug appears to be related to the "Complex rel exp causes exception" bug described at http://shark.armchair.mb.ca/~dave/relforum/viewtopic.php?f=2&t=104. I've fixed the other bugs noted on September 26th and on October 6th, but these two are proving difficult. Both seem to d...

Since I posted this one I've discovered that when an insert fails because of a mistake that gives rise to a constraint violation, and you then correct that mistake, the second insert reports twice as many tuples as it should have. It appears to have counted the ones on the failed insert as well as ...

I should be able to fix this for the next update.

I'll fix this in the next update.