Re: LOBS or not ?

4K is a bit of a nuisance size - the probability of wasting a lot of space, and/or producing chained rows is high. (What is your block size ?)

LOBs are really targeted as large objects, not small but annoying objects, and on the 4K, boundary you need to know a lot about how LOBs work, and how your application is going to work, to make a sensible choice. For example - are your texts subject to frequent, partial, updates ?

The parent/child mechanism, of

    'article description' / 'article text' may be right for you - but if you took it, and your texts were pretty static, I would consider looking at a much smaller number of bytes of text per row (even down to a few hundred) as this could pack the data better without compromising the speed of data access.

--
Jonathan Lewis
Yet another Oracle-related web site:  http://www.jlcomp.demon.co.uk

Practical Oracle 8i:  Building Efficient Databases
Publishers:  Addison-Wesley

Reviews at: http://www.jlcomp.demon.co.uk/book_rev.html



Markus Fischer wrote in message ...


>

>"Daniel A. Morgan" <dmorgan_at_exesolutions.com> schrieb im Newsbeitrag

>news:3AFE35E9.5C604710_at_exesolutions.com...

>> Markus Fischer wrote:

>>

>> > Hi,

>> >

>> > For some Webapplication articels are stored in an Oracle DB. They

 sometimes


>> > can exceed the normal varchar column size of 4000 chars. Up today

 they're


>> > just stored in multiple 4000 char-sized columns. So, in PHP, its quiet

 easy


>> > to select an article by doing 'SELECT * from Article WHERE id = 100'

 and


>> > then concatenating the columns in the right order.

>> >

>> > Is there any advantage of using LOB's here ? Using LOB's from a

>> > programmatically view needs some overhead to get dealt with.

>> >

>> > thanks,

>> >

>> > - Markus

>>

>> I don't think it is a question of advantages. It is rather a question of

 the


>> fact that you have no choice but to use LOBs. There is nothing else

 larger
 than


>> 4K bytes that will be in the next version of Oracle AFAIK.

>

>    I know but you can also solve this limitation by creating more columns

>with 4kb or create a second table with a single 4k column and do multiple

>entries if an text article or whatever is too long.

>

>But, is there any advantage using LOB <-> multiple 4k columns ?

>

>Just looking at the SQL query it's more overhead to deal with LOB's.

>

>- Markus

>

>