New To PostgreSQL

I am attempting to convert an database currently running on Informix to
a free database on Linux (RedHat 6.1).  I have a question.....

I learned that MySQL, does not maintain foreign keys, which affects me
because I need to use things like CHECK in the CREATE TABLE statements.
So thats why I am not trying PostgreSQL.  Does PostgreSQL support
foreign keys?  Are there any other quirks I might run into as far as
SQL syntax goes?

Thank In Advance,

Thomas Ince
Software Systems Engineer
Atlantic Consulting Services
Shrewsbury, NJ
tince@acsinc-nj.com