Rename (relational algebra)
In relational algebra, a rename is a unary operation written as  where:

  is a relation
  and  are attribute names
  is an attribute of 

The result is identical to  except that the  attribute in all tuples is renamed to . For an example, consider the following invocation of  on an  relation and the result of that invocation:

Formally, the semantics of the rename operator is defined as follows:

 

where  is defined as the tuple , with the  attribute renamed to , so that:

References 

Relational algebra