Dates in Primary Keys/Unique Index

I have a task to crunch through a physical database created right out of the ERWIN datamodeling tool. I have a few questions: 1) Is there a problem/trade-offs using dates in a composite primary key? For example where the primary key is CUSTOMER_NUM + CALL_DATE. 2) Does it make sense to put the CALL_DATE first if it would be more selective than CUSTOMER_NUM? 3) Are there any advantages/disadvantages of creating a unique index on a column prior to making the same column a primary key? I am using ODS 7.22 on SUN Solaris 2.5.1. I don't have alot of information on performance requirements and usage patterns (not good) so I am looking for general comments. Thanks! -- Bob Carts - SAIC rcarts@agccs.lmco.com 703-813-2914