writing a simple sql parser and database program

Hi,

I would like to learn how to write a simple SQL parser and database
program. This is for an embeded situation where I can't use a database
program like postgre. Jumping into the postgre source code seems a
little overwelming as I don't have a general understanding of how this
is done. Is there a link or book that explains the basics of how a
database parses SQL and how it then operates on the data?

Thank you,
Peter