i would like to know when i create a table with identity column,
should i used generated by default or generated as always. since when
i create this table, i might copy some data from another table with
identity column also, (so if i use generated as always, i can't do
insert into new_tables select * from old_table), then i might also
insert new data into this new table (if i do generated by default,
then the new table could have the same identity column value as the
data i copy from another table. please advice

db2group88@yahoo.com wrote:
[color=blue]
> i would like to know when i create a table with identity column,
> should i used generated by default or generated as always. since when
> i create this table, i might copy some data from another table with
> identity column also, (so if i use generated as always, i can't do
> insert into new_tables select * from old_table), then i might also
> insert new data into this new table (if i do generated by default,
> then the new table could have the same identity column value as the
> data i copy from another table. please advice[/color]

The reason people use 'generated always' is so that the database will
prevent users (or applications) from inserting their own values into
the identity column, no matter what. When a user can assign a value
to an identity column you run the risk of causing problems when the
identity runs into a duplicate value.

It is possible to LOAD data into a generated-always column using LOAD
with the MODIFIED BY IDENTITYOVERRIDE option. If you do this, though,
make sure you set the appropriate starting point for your identity to
avoid conflicting values.


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i am not using load utility, i am using sql command like insert in the
jdbc application.

Ian <ianbjor@mobileaudio.com> wrote in message news:<41052af4$1_1@corp.newsgroups.com>...[color=blue]
> db2group88@yahoo.com wrote:
>[color=green]
> > i would like to know when i create a table with identity column,
> > should i used generated by default or generated as always. since when
> > i create this table, i might copy some data from another table with
> > identity column also, (so if i use generated as always, i can't do
> > insert into new_tables select * from old_table), then i might also
> > insert new data into this new table (if i do generated by default,
> > then the new table could have the same identity column value as the
> > data i copy from another table. please advice[/color]
>
> The reason people use 'generated always' is so that the database will
> prevent users (or applications) from inserting their own values into
> the identity column, no matter what. When a user can assign a value
> to an identity column you run the risk of causing problems when the
> identity runs into a duplicate value.
>
> It is possible to LOAD data into a generated-always column using LOAD
> with the MODIFIED BY IDENTITYOVERRIDE option. If you do this, though,
> make sure you set the appropriate starting point for your identity to
> avoid conflicting values.
>
>
> -----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
> http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
> -----== Over 100,000 Newsgroups - 19 Different Servers! =-----[/color]