Can some one explain the Pros and Cons of using Identity columns?
-Rp?
-Rp?
Pro: they're a very fast way of generating sequential numbers (sinceQuote:> Can some one explain the Pros and Cons of using Identity columns?
> -Rp?
Cons: in pre-12.0: there's a risk of "identity gaps", see
www.sypron.nl/idgaps.html for details.
In 12.0+: identity gaps can be limited or avoided with the
'identity_gap' setting -- when you use this, there are few
disadvantages left (but those are solved in 12.5.0.3 and 12.5.1).
HTH,
Rob
-------------------------------------------------------------
Rob Verschoor
Certified Sybase Professional DBA for ASE 12.5/12.0/11.5/11.0
and Replication Server 12.5
New book(coming soon): 'Tips, Tricks & Recipes for Sybase ASE'
For details, see http://www.sypron.nl/ttr
http://www.sypron.nl
Sypron B.V., P.O.Box 10695, 2501HR Den Haag, The Netherlands
-------------------------------------------------------------
see http://www.sypron.nl/idgaps.html
--
Posted via http://dbforums.com
-am ? 2003
> > In 12.0+: identity gaps can be limited or avoided with the
> > 'identity_gap' setting -- when you use this, there are few
> > disadvantages left (but those are solved in 12.5.0.3 and 12.5.1).
> What disadvantages have been solved in 12.5.x?
> -am ? 2003
Rob
-------------------------------------------------------------
Rob Verschoor
Certified Sybase Professional DBA for ASE 12.5/12.0/11.5/11.0
and Replication Server 12.5
New book(coming soon): 'Tips, Tricks & Recipes for Sybase ASE'
For details, see http://www.sypron.nl/ttr
http://www.sypron.nl
Sypron B.V., P.O.Box 10695, 2501HR Den Haag, The Netherlands
-------------------------------------------------------------
-am ? 2003
1. pros/cons of computed(?) columns
i've got a table that that grows by roughly 25,000 rows per year. i've
got two columns c1 char(2) and c2 char(2). the concatenation of c1 and
c2 is used in another table as basically a foreign key. i added a
column c3 where the formula is c1 + c2. any drawbacks to this? the
only reason i've done this is because users are writing their own
queries in access and need to be able to see the correct relationships
between the two tables.
ch
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