The Tuple Relational Calculus

1. The tuple relational calculus is a nonprocedural language. (The relational algebra was procedural.)

   We must provide a formal description of the information desired.

2. A query in the tuple relational calculus is expressed as

   

   i.e. the set of tuples for which predicate is true.

3. We also use the notation
   • to indicate the value of tuple on attribute .
   • to show that tuple is in relation .

• Example Queries
• Formal Definitions
• Safety of Expressions
• Expressive Power of Languages