Re: Primary key definition?

On 10/22/19 2:47 PM, stan wrote:
> I  started doing the following to define my primary keys long ago and in a
> universe far away:
>
> CREATE TABLE employee (
> employee_key           integer DEFAULT nextval('employee_key_serial')
> PRIMARY KEY ,
>
> WEE ran into a scenario, after a total db restore on a project where we got
> errors inserting new data because the keys were duplicated. Looking at a
> pg_dump, it appears to me that I now understand why. Although the values f
> the keys, and the data structures that reference them look like they will
> get restored correctly, it appears to me that the sequences get recreated with
> an initial value of 1, which means that on the next insert we will get 1 for
> a key, which likely is already used. Looks like this is a different way of
> defining this:
>
>
> CREATE TABLE books (
> id              SERIAL PRIMARY KEY,
>
> Which has the advantage of not having to manually create the sequences. Will
> this also enforce that the "internally created sequence" will be initialized
> to a value above the maximum key in use on a pg_restore?

When I restored an 8.4 database to 9.6 using pg_dump/pg_restore, all of the 
sequences were restored using the sequence values at the time the pg_dump ran.


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