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Describing Relational Algebra Operations

We define the semantics of RA operations using
  • "conditional set" expressions   e.g. { x | condition }
  • tuple notations:
    • t[ab]   (extracts attributes a and b from tuple t)
    • (x,y,z)   (enumerated tuples; specify attribute values)
  • quantifiers, set operations, boolean operators
Notation: r(R) means relation instance r based on schema R