yes create one more table

1)WRegn Master where WRegnNum is PK having(WRegnNum PK,Wregname,Address_id,NumOfEmployees)

2)Workplace (Workplacecode PK,WRegnNum,Empid)

3)EmployeeMaster

4)AddressMaster

so Data will not repeat and save your size and everything

now as far as join concern

still i am not getting what you want

you want all WRegn having employee or not having (use Left Join)

you want all WRegn having employee (use Inner join)

you want all employee having region or not(Use right join)