Re: Using varchar primary keys.

On 02/04/13 06:35, jesusthefrog wrote:
> On the topic of 'natural' versus 'synthetic' primary keys, I am
> generally in the camp that an extra ID field won't cost you too much,
> and while one may not need it for a simple table (i.e. id, name) one
> might add any number of columns later, and you'll be glad to have it.

Definitely, a lookup table can be extended to hold all kinds of
statistics and translations on a "tag". I didn't look too deeply into
the actual usage (not sure if any real examples where given). But ON
UPDATE CASCADE if not a feature I would recommend in this context
(referencing a PK) if at all.

> I am, however, against using sequences (or serial integers in Postgres)
> for reasons of scaling and replication across multiple copies of a
> database running on different servers.
>
> My preferred method is to give every table an ID column of UUID type and
> generate a UUID using the uuid-ossp contrib module. This also prevents
> someone not familiar with the database design from using an ID somewhere
> they should not (as is possible with natural PKs) or treating the ID as
> an integer, not an identifier (as is all too common with serial integers).
>

It was instagrams own implementation, but mentions twitters "Snowflake".
Interesting read still only requires a bigint.
http://goo.gl/gRlXC

IMO uuid is convenient but large and for all that data it doesn't hold
anything useful. I have been tempted though.

Jules.