tailieunhanh - Giáo trình SQL Bài 12

Tham khảo tài liệu 'giáo trình sql bài 12', công nghệ thông tin, cơ sở dữ liệu phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | The Relational Algebra and Relational Calculus - 2 0 UNIVERSITY Objectives Relational Algebra Binary Relational Operations Additional Relational Operations Examples of Queries in Relational Algebra Relational Calculus Tuple Relational Calculus Domain Relational Calculus Reference Chapter 6 Faculty of Science and Technology Database Fundamentals 2 A HOASEN ÎlVjJ university Binary Relational Operations JOIN JOIN Operation denoted by M The sequence of CARTESIAN PRODUCT followed by SELECT is used quite commonly to identify and select related tuples from two relations A special operation called JOIN combines this sequence into a single operation This operation is very important for any relational database with more than a single relation because it allows us combine related tuples from various relations The general form of a join operation on two relations R A1 A2 . . . An and S B1 B2 . . . Bm is R M join condition S where R and S can be any relations that result from general relational algebra expressions. Faculty of Science and Technology Database Fundamentals