Study Notes on Introduction to the Relational Model

Introduction to the Relational Model

Overview of the Relational Model

  • The relational model is the primary data model for commercial data-processing applications.
  • Key characteristics:
    • Simplicity: Eases the tasks for programmers compared to earlier models like the network model or hierarchical model.
    • Adaptability: Retains relevance by incorporating new features such as:
    • Object-relational features: Enables complex data types and stored procedures.
    • Support for XML data.
    • Tools for handling semi-structured data.
  • Independence: The model is not tied to specific underlying low-level data structures, allowing it to persist alongside new storage approaches like modern column-stores designed for large-scale data mining.

Structure of Relational Databases


  • A relational database comprises a collection of tables, each with a unique name.

  • Example tables:


  1. Instructor Table



    • Stores information about instructors, including the following columns:

  • ID: Unique identifier for each instructor.
  • name: Instructor's name.
  • dept_name: Department to which the instructor belongs.
  • salary: Instructor's salary.


  • Example entries:

    		• IDnamedept_namesalary
      10101SrinivasanComp. Sci.65000
      12121WuFinance90000
      15151MozartMusic40000
      22222EinsteinPhysics95000
      32343El SaidHistory60000
      33456GoldPhysics87000
      45565KatzComp. Sci.75000
      58583CalifieriHistory62000
      76543SinghFinance80000
      76766CrickBiology72000
      98345BrandtComp. Sci.92000
      -KimElec. Eng.80000

    • Course Table

      • Stores information about courses with the following columns:
        • course_id: Unique identifier for each course.
        • title: Name of the course.
        • dept_name: Department offering the course.
        • credits: Number of credits for the course.
        • Example entries:
          		• courseid | title | deptnamecredits
            ------------------------------------------------------------
            BIO-101Intro. to BiologyBiology4
            BIO-301GeneticsBiology4
            BIO-399Computational BiologyBiology3
            CS-101Intro. to Computer ScienceComp. Sci.4
            CS-190Game DesignComp. Sci.4
            CS-315RoboticsComp. Sci.3
            CS-319Image ProcessingComp. Sci.3
            CS-347Database System ConceptsComp. Sci.3
            EE-181Intro. to Digital SystemsElec. Eng.3
            FIN-201Investment BankingFinance3
            HIS-351World HistoryHistory3
            MU-199Music Video ProductionMusic3
            PHY-101Physical PrinciplesPhysics4

          • Prerequisite Table

            • The prereq table stores prerequisite courses for each course with the following columns:
              • course_id: Identifier for the course.
              • prereq_id: Identifier for the prerequisite course.
              • Each row consists of a pair of course identifiers indicating that the second course in the pair is a prerequisite for the first course. Thus, it shows relationships in a schema.

                • Key Concepts and the Theoretical Framework

                • A substantial theoretical framework underpins relational databases.
                  • Further study includes:
                  • Design of relational database schemas (covered in Chapters 6 and 7).
                  • Efficient processing of queries (discussed in Chapters 15 and 16).
                  • Formal relational languages for advanced study (explored in Chapter 27).