Jan 12 2009

What Determines Context Order?

Categories: Universe Contexts,Universe Design Dave Rathbun @ 12:24 am

It might not be obvious, but when you are looking at the “list mode” screen in the Universe Designer product there is a method to the madness that is the order of the joins displayed. The joins are – believe it or not – displayed in chronological order based on when they were created. This can help when you have to include a new join in a context as it will always be at the end of the list. I have become used to that feature.

But I have yet to figure out how the contexts are ordered on the same screen. Has anyone ever noticed a pattern as to how the order of contexts is determined? If so, I would love to hear it. 😎

6 Responses to “What Determines Context Order?”

  1. Comment by Dwayne Hoffpauir January 13th, 2009 at 9:15 am

    Darn! I thought that WAS the question you were answering! I’ve never been able to figure out a pattern either.

  2. Comment by Amalka April 12th, 2009 at 6:36 am

    Hi Dave

    I was wondering whether you prefer to use context or alias to resolve loops. I used to prefer aliases but am now looking at using contexts to avoid having so many alias tables and objects.

    But this is a major effort when building a universe on top of an ODS (not usually done anyway)

    Cheers,
    Amalka

  3. Comment by Dave Rathbun April 13th, 2009 at 3:47 pm

    Hi, Amalka, there really isn’t any “preference” involved in picking between contexts or aliases. One technique will generally be appropriate in any given situation and the other will not be. There is a “sticky” topic in the Semantic Layer forum on BOB with lots of posts from various folks (including myself) on this issue. 🙂

  4. Comment by Tamir Bar-Netzer April 25th, 2009 at 10:43 am

    Hi,

    Although this is not exactly the question on stake, the order of the contexts is implemented alphabetically in a situation where a join belongs to more than one context, and the context ‘chooser’ is not required . I do not recall now, but there were instances this information was crucial to understanding the generated sql.

    Tamir

  5. Comment by Frank May 27th, 2009 at 3:33 am

    Hi Dave,

    Do you have a hint, how one can determine the order of tables used in a query.
    In some cases there is a difference between questioning FROM a, b instead of FROM b, a.

    Determing the order in derived tables is a solution minor sufficient for me.
    So abstraction of your article above led me to a ‘chronological’ one – it works, but somewhere there also might be a flag you can tell about, can you?

    Kind regards
    Frank

  6. Comment by SuperDeano March 1st, 2010 at 10:00 am

    Hi Dave,

    I posted this question on BOB some time ago with no success. I then contacted Tech Support, asking:

    1. Is there a way to sort the contexts in designer?
    2. If not, can they explain how they are sorted by default?

    Answers:

    1. No
    2. Don’t know

    Thanks,
    Ewan