Re: Q:Object query (nested tables?) vs query on normalized tables

Excellent! Thank you very much.

Mike

Jonathan Lewis wrote in message
<979085947.15666.0.nnrp-12.9e984b29_at_news.demon.co.uk>...
>
>You can index the nested tables,
>but you may have to go through some
>slightly 'counter-intuitive' steps to get
>data in and out.
>
>The main performance overhead will
>probably be due to the space taken
>up by the introduction of what are effectively
>surrogate keys that you could otherwise
>choose not to use.
>
>I wonder if I could mention at this point
>"Chapter 16 Collection Objects" in my book
>which may answer a lot of your questions
>and give you some extra ideas as well.
>
>--
>Jonathan Lewis
>Yet another Oracle-related web site: http://www.jlcomp.demon.co.uk
>
>Practical Oracle 8i: Building Efficient Databases
>
>Publishers: Addison-Wesley
>See a first review at:
>http://www.ixora.com.au/resources/index.htm#practical_8i
>More reviews at: http://www.jlcomp.demon.co.uk/book_rev.html
>
>
>
>gnn_gnn wrote in message <93g8t3$3hs$1_at_slb7.atl.mindspring.net>...
>>Hi Jonathan:
>>
>>It kind of looked like it was, because the docs talk about "hidden
 columns",
>>etc. So it isn't necessarily any BETTER performance-wise. What are the
>>odds of it being worse? Can one make indexes on these phantom tables,
 etc.
>>or if I want to search for credit card transaction data (as in my example)
>>am I doing full table scans left and right?
>>
>>Thanks,
>> Mike
>>
>>
>>
>>Jonathan Lewis wrote in message
>><979068270.22040.1.nnrp-10.9e984b29_at_news.demon.co.uk>...
>>>
>>>Nested tables are implemented as normlised tables
>>>with a meaningless key combined with a hidden
>>>unique constraint on the parent table, so it's all
>>>overhead and no (physical) benefit over doing it
>>>the relational way.
>>>
>>>
>>>--
>>>Jonathan Lewis
>>>Yet another Oracle-related web site: http://www.jlcomp.demon.co.uk
>>>
>>>Practical Oracle 8i: Building Efficient Databases
>>>
>>>Publishers: Addison-Wesley
>>>See a first review at:
>>>http://www.ixora.com.au/resources/index.htm#practical_8i
>>>More reviews at: http://www.jlcomp.demon.co.uk/book_rev.html
>>>
>>>
>>>
>>>gnn_gnn wrote in message <93ebi5$t56$1_at_nntp9.atl.mindspring.net>...
>>>>Hi:
>>>>
>>>>I have been looking at the documentation on defining types, objects,
 nested
>>>>tables, etc. in Oracle 8i and have a basic question on the topic as a
 NB.
>>>>Some of these things look very interesting, like points, lines, etc.
 But
>>>>how does the query speed stack up? For example, if I wanted a list of
>>>>people and all of their credit card transactions for a month (or several
>>>>months) and wanted to do queries like "show all the people, and the
>>>>transactions who spent more than $200 on clothes in the month of
 december".
>>>>Would I be better off using something like nested tables
 (performance-wise)
>>>>or breaking out the credit card transactions into a separate table with
 a
>>>>foreign key back to the user table? What are the pros and cons of each
>>>>method?
>>>>
>>>>Thanks,
>>>> Mike
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>
Received on Tue Jan 09 2001 - 20:23:36 CST