[DUG] MSSQL Question

[Neven MacEwan]

John

Really interbase generators are more akin to the mssql identity column 
type, the problem with mssql identity columns WAS
with the @@Identity variable which was per connection (and hence 
triggers that inserted other identity columns not return the identity
you would expect),  this has been 'fixed' with the SCOPE_IDENTITY() function

Stangely identity columns and generators behave the same way, ie they 
are both not rolled back by a trans

PostgeSQL, uses a combo of both a column type of 'serial', which auto 
generates a 'sequence'

Of course I could be spouting BS.

Neven
//
> Whats others opinion on the merits of trggers etc as discussed here vs the 
> Firebird/Interbase method of using generators?
>
> I have often wondered if this is an area where Firebird/Interbase has a less
> convenient but more transparent mechanism - where you have to fire a
> generator to get a new key value before you start putting data in a new
> record.
>
> And the generator never rolls back even if the transaction does - avoiding 
> the lock problem.  Mostly in
> my experience this is fine, except some times when the ID numbers (eg batch
> numbers) are supposed to be strictly sequential and then you have to get the
> next value from a SQL query, and make sure no-one else is running another of
> the same batch at the same time.  (In those situations the main thing that
> protects the database is that only one staff member ever runs this batch
> operation - I bet thats how a lot of databases run in practice)
>
>
> John
>
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