Re: More than 254 cols in table?

In a previous posting, Steven Whatley (swhatle_at_starbase.neosoft.com) writes:
> The common attributes associated a telephone needs to be a
> column in the same table as the phone number like your example below.
>
> : ID: _______ City: _______ Telephones:_________
>

   Indeed, when we do need to break an entity up we try to keep columns which are frequently accessed together on the same table.

> Now for questions such as "Which word processor did you buy in the last six
> months?", "How many copies did you buy?", and "Do you plan to upgrade when
> a new version comes availible?" would work better with a scheme like the
> one mentioned above. At least, it would seem that way to me.

   These are questions which only look at one attribute at a time. The complications arise when you need to look over multiple attributes to obtain your desired information.

> This is a very good thread.

   It's a very interesting problem. I regularly get developers coming to me who have run into the 254 limit and are looking for help. They often end up puting together interesting solutions. Just this week a Forms 4 developer was showing me how he had "Intermixed" two blocks on his form (from two underlying base tables) and coordinated the two as to appear as a single block. He was looking for a way to get one block's scroll bar to control both blocks (If Steve Muench is listening & has any ideas please speak up). He ended up putting a couple of buttons next to the blocks and id doesn't look bad at all.

> Creating a enormous database with an item whcih
> could have many, many attributes is a difficult problem. With the current
> technology, compromises have to be made. Determining where to or not to
> compromise is the crux of the problem (and why some people get paid the big
> bucks). I look forward to reading the articles to come

   Oracle is doing R&D towards adding multidimensional extensions to the RDBMS for temporal and spatial data. I think it is romoured to be part of "Oracle8" along with object oriented stuff. Maybe this will make it more natural to store this type of information.

--
   - Doug Harris
     Database Administrator, System Development Division,
     Statistics Canada.        ## WHERE ALL_OPINIONS.OWNER = USER ##