1.2.07. Project operation

  • PROJECT a subset of attributes for all tuples from a relation
    • Pi (p)
    • p<attribute list>(R)
  • If sublist is only non-key attributes
    • might get duplicates
  • Removes duplicates
  • Attribute list:sublist example

The result set of the operation is itself a relational. That output relation will contain the same number of rows as the input, however it may contain a different number of columns; fewer if a subset of attributes is projected; more if derived or aggregated attributes are included.