/* 
Populate the NextKeyValue table. Set all the initial values to 0 so the first key generated for each key type will be 1.
*/
INSERT INTO NextKeyValue (KeyName, KeyValue) VALUES ("EmployeeId", 1)
INSERT INTO NextKeyValue (KeyName, KeyValue) VALUES ("DepartmentId", 1)
INSERT INTO NextKeyValue (KeyName, KeyValue) VALUES ("AccountId", 1)

/* Now run the following scripts from separate connections */

-- Connection #1
begin tran
exec GetNextKeyValue "EmployeeId"

--Connection #2

sp_who

begin tran
exec GetNextKeyValue "DepartmentId"

--Connection #3
begin tran
exec GetNextKeyValue "AccountId"

--Connection #4
begin tran
exec GetNextKeyValue "AccountId"