5. Relational Calculus

ЁЯУР Relational Calculus

Relational Calculus рдПрдХ┬аnon-procedural query language┬ард╣реИред
рдпрд╣ рдмрддрд╛рддреА рд╣реИ┬ардХреНрдпрд╛ data рдЪрд╛рд╣рд┐рдП, рди рдХрд┐┬ардХреИрд╕реЗред

Types:

  1. Tuple Relational Calculus (TRC)
  2. Domain Relational Calculus (DRC)

тЬЕ Advantages of Relational Calculus

  • SQL рдХрд╛ theoretical base
  • High level abstraction
  • DBMS рдЦреБрдж query optimize рдХрд░рддрд╛ рд╣реИ

тЭМ Disadvantages of Relational Calculus

  • Beginners рдХреЗ рд▓рд┐рдП рдХрдард┐рди
  • Directly DBMS рдореЗрдВ use рдирд╣реАрдВ рд╣реЛрддрд╛
  • Complex expressions рд╕рдордЭрдирд╛ рдореБрд╢реНрдХрд┐рд▓

ЁЯЧВ Advantages of DBMS

  • Data redundancy рдХрдо
  • Data consistency рдмрдиреА рд░рд╣рддреА рд╣реИ
  • Security, Backup, Recovery available
  • Multi-user access support

тЪая╕П Disadvantages of DBMS

  • High cost
  • Complex system
  • High resource usage
  • Central failure рдХрд╛ risk