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CS403: Introduction to Modern Database Systems

Unit 6: Relational Algebra
We have seen that database entities can be viewed as logical tables. While this is useful in its own way, we can learn more from the data if we can perform operations on the tables within a database, as data from one table may not be meaningful without the data from another table. In this unit, we will introduce relation algebra, the mathematical notation used to represent how data retrievals and updates are performed on tables in a database. Understanding relational algebra will serve as a prelude to using the Structure Query Language (SQL).

Completing this unit should take you approximately 5 hours.
- Unit 6 Learning Outcomes Page
- 6.1: Basic Operations
  - Gordon Russell's "Relational Algebra"
    Read this section.
  - Gordon Russell's "Relational Algebra Example"
    Read this section.
- 6.2: Derived Operations
  - Marquette University: Charles Corliss' "Relational Algebra and the Relational Calculus"
    Read this page.
  - University of Houston at Clear Lake: Gary Boetticher's "Relational Algebra: Set Operations" Page
    Watch this lecture.
- 6.3: Set Operations
  - Stanford University: "Table Variables and Set Operators" Page
    Watch this lecture.
- 6.4: Aggregate Functions
  - City University of New York: Richard Holowczak's "Aggregate Functions” URL
    Read the "Aggregate Functions" and "Aggregate Functions Examples" sections.
- 6.5: Assessment
  - Gordon Russell's "Relational Algebra Quiz" URL
    Take this quiz.