novice question

i'm running postgresql on apache with php4. i am working with a postgresql
table which was set up by an employee of mine who no longer works for the
company. this employee set up constraints to the table, some of which won't
work properly, ie. rejected due to CHECK constraint.

how do i find out what the check constraints are currently?
how do i change the check constraints?

i've located in the book postgresql by bruce momjian how to set up the
constraints, but can't find how to find answers to the questions above. any
help would be most appreciated.

how can i count how many users are logged in at the current time?

does anyone know of a good novice user group for linux or php4?

thanks,

andy arledge
www.neighborhoodsingles.com