We are preparing to convert a MS SQLServer7 database and have been
desiging all the tables with PrimaryKeys of Char(20)

Most of our tables are moderate size with a few tables around 500,000
to 1 million records.

Most of our queries appear to be fast... but now we are worried we
should have used an BIGINT (Int64) instead of our Char(20) for our
PK's...

I believe Ann once stated that a BIGINT and a Char(8) would be
equivelant in the time it takes to compare values... so then a Char
(20) would be 2.5 times longer... if my math isn't too rusty.

What are most people using for PK's?

and can you _please_ offer your suggestions because we really want to
hear something that will either push us one way or make us feel like
we are sitting OK...

Many thanks,
--Raymond