Re: Trends in Using Oracle 10g Object Extensions

From: DA Morgan <damorgan_at_x.washington.edu>
Date: Fri, 04 Feb 2005 11:28:45 -0800
Message-ID: <1107545162.200353@yasure>

Mark C. Stock wrote:

> "DA Morgan" <damorgan_at_x.washington.edu> wrote in message 
> news:1107486745.51433_at_yasure...
> 

>>Lee Chalupa via OracleMonster.com wrote:
>>
>>
>>>I realize that most of the installed databases in organizations are
>>>relational databases versus some kind of object oriented persistence.
>>>
>>>Being a Java Developer and working with objects, I'm interested in
>>>learning the object extensions in 10g such as object types,
>>>object tables, nested tables, varrays, etc. I've read some of the
>>>database-guy blogs and most of them are not too excited about these
>>>object extensions and recommend avoiding them. After playing with some of
>>>the syntax for nested tables, I can see why.
>>>
>>>I'd like to know if there are any apps out there that are using these
>>>extensions, what you have learned from the experience, and what you would
>>>recommend to a future application.
>>>
>>>Thanks
>>>
>>>Lee
>>
>>They are problematic when used in tables but are very very useful when
>>defining object-views based on relational tables and essential when
>>working with many of Oracle's built-in packages.
>>
>>Most of those that refuse to use them ... also refuse to write any
>>code or learn anything newer than Oracle 8.0.6.
>>--
>>Daniel A. Morgan
>>University of Washington
>>damorgan_at_x.washington.edu
>>(replace 'x' with 'u' to respond)

> 
> 
> 
> "They are problematic when used in tables " --- could you elaborate?
> 
> ++ mcs 

Tom Kyte has elaborated on this quite a bit and with great hesitancy I will too.

The problem I see is that the object tables don't have any real referential integrity. A REF is just that a reference. One can pretty much violate it at will. Delete the object refered to and nothing happens. Not something you can do with a Foreign Key constraint.

Here are Tom's comments from "Expert one-on-one Oracle." Now for an opinion. The object relational components (nested tables, object tables) are primary what I call 'syntactic sugar'. They are always translated into 'good old' relational rows and columns. I prefer not to use them as physical storae mechanisms personally. There are too many bits of 'magic' happening - side effects that are not clear. You get hidden columns, extra indexes, surprise pseudo columns, and so on.

He writes much more on the subject but that should give you a sense of his thinking. Mine, more simply put, is that I want a referential constraint that is as tough as gorilla glue.

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu
(replace 'x' with 'u' to respond)

Received on Fri Feb 04 2005 - 13:28:45 CST