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The result is identical to R except that the b attribute in all tuples is renamed to a. For an example, consider the following invocation of ρ on an Employee relation and the result of that invocation:
Name
EmployeeId
Harry
3415
Sally
2241
EmployeeName
EmployeeId
Harry
3415
Sally
2241
Formally, the semantics of the rename operator is defined as follows:
where is defined as the tuple t, with the b attribute renamed to a, so that: