Dear Friend,
An employee code is used for:
Identification - for example the code maybe zhc07
Z - may be the starting name of the company - eg Zebra
h - maybe the starting letter of the hr dept
c - may be a for contract roll employees
07 - is the persons unique identification code.
There may be the same name and initial and even birtdays for a few people...
So inorder to prevent confusions in retrieving somones information - an unique code is used for referrign to employees details. Maybe when the HR / admin person keys in the code, they will get all information related to salary - pf , loan, grievances, promotions...etc.
Using the code will be more helpful, than the name
It can be used for attendance marking (automated system will need some bar codes..and eventually the data will be fed in for the particular code)
morever - its an identification