Re: Drawbacks of using BYTEA for PK?

D. Dante Lorenso wrote:
> GUID?  Isn't that really nothing more than an MD5 on a sequence?
> 
>    SELECT (MD5(NEXTVAL('my_table_seq'))) AS my_guid;

I know there are several algorithms to generate GUID, but this is 
certainly inadequate :-) You need to make sure that the generated GUID 
will be unique throughout cyberspace (or to be more precise, the GUID 
should have a very very small chance of colliding with other people's 
GUID). Even OID is not a good seed at all.

Perhaps I can make a GUID by MD5( two random numbers || a timestamp || a 
unique seed like MD5 of '/sbin/ifconfig' output)...

> Since 7.4 has the md5 function built-in, there's your support ;-)

Well, until there's a GUID or INT128 or BIGBIGINT builtin type I doubt 
many people will regard PostgreSQL as fully supporting GUID. I believe 
there's the pguuid project in GBorg site that does something like this.

-- 
dave