Should primary keys be always assigned as clustered index

Question

I have a SQLServer table that stores employee details, the column ID is of GUID type while the column EmployeeNumber of INT type. Most of the time I will be dealing with EmployeeNumber while doing joins and select criteria's.

My question is, whether is it sensible to assign PrimaryKey to ID column while ClusteredIndex to EmployeeNumber?

Answer 1

The ideal clustered index key is:

1. Sequential
2. Selective (no dupes, unique for each record)
3. Narrow
4. Used in Queries

In general it is a very bad idea to use a GUID as a clustered index key, since it leads to mucho fragmentation as rows are added.

EDIT FOR CLARITY:

PK and Clustered key are indeed separate concepts. Your PK does not need to be your clustered index key.

In practical applications in my own experience, the same field that is your PK should/would be your clustered key since it meets the same criteria listed above.