Question

Consider the following two tables where EmployeeNum is primary key in both tables. What is the result of combining the two tables? Employee (EmployeeNum, LastName, FirstName, WageRate, SocSecNum, DepartmentNum) Employee (EmployeeNum, LastName, FirstName, Street, City, State, PostalCode)

Answer 1

Answer:

The result of combining the both tables is:

Employee(EmployeeNum, LastName, FirstName, WageRate, SocSecNum, DepartmentNum, Street, City, State, PostalCode)

Explanation:

Since the EmployeeNum is the primary and it is available in both tables, what happens is that, it will not list the primary key column twice. It will list the primary key first then all the other attribute in the first table followed by the attribute in the second table. And it will take note so as not to repeat attribute that already occur in the first table.

For instance; in this case, besides EmployeeNum, LastName and FirstName also appear in the both tables but only one instance of them were listed in the resulting table.