State and/or district defined Pre-requisites for a course are able to be coded in the CRS table and honored via the HIS table during scheduling. For example Alg 1 credit is a state pre-requisite for Chemistry in Texas. We could code alg 1 as a pre-req on the Chem CRS record and when scheduling the SIS would evaluate HIS to determine if the pre-req was met. If not, an error message would pop up when attempting to schedule a student without the pre-req, with the ability to override the error message.