Erweiterte Operatoren und Multimengen

Betrachte die folgenden beiden Relationen:

  • ´R(A,B) := {(0,1), (2,3), (0,1), (2,4), (3,4)}´
  • ´S(B,C) := {(0,1), (2,4), (2,5), (3,4), (0,2), (3,4)}´

Gib die Ergebnisse der folgenden Anfragen an:

  1. ´delta(S)´ (1P)
  2. ´gamma_(B,avg(C))(S)´ (1P)
  3. ´R |⋈ S´ (1P)
  4. ´R ⋊ S´ (1P)
  5. ´R |⋈| S´ (1P)
  6. ´R |⋈|_(R.B < S.B) S´ (1P)
Solution

    1. ´{(0,1), (2,4), (2,5), (3,4), (0,2)}´

    2. ´{(0,1.5), (2,4.5), (3,4)}´

    3. ´{(0,1,"NULL"), (2,3,4), (2,3,4), (0,1,"NULL"), (2,4,"NULL"), (3,4,"NULL")}´

    4. ´{(3,4), (3,4)}´

    5. ´{(0,1,"NULL"), (2,3,4), (2,3,4), (0,1,"NULL"), ´ ´(2,4,"NULL"), (3,4,"NULL"), ("NULL",0,1), ´ ´("NULL",2,4), ("NULL",2,5), ("NULL",0,2)}´

    6. ´{(0,1,2,4), (0,1,2,5), (0,1,3,4), (0,1,3,4), ´ ´(2,3,"NULL","NULL"), (0,1,2,4), (0,1,2,5), (0,1,3,4), ´ ´(0,1,3,4), (2,4,"NULL","NULL"), (3,4,"NULL","NULL"), ´ ´("NULL","NULL",0,1), ("NULL","NULL",0,2)}´

  • URL:
  • Language: Deutsch
  • Subjects: Databases
  • Type: Calculate
  • Duration: 20min
  • Credits: 6
  • Difficulty: 0.4
  • Tags: relation query multiset
  • Note:
    HPI, 2015-06-01, Datenbanksysteme 1, Aufgabe 2.2
  • Created By: adius
  • Created At:
    2015-07-26 21:30:04 UTC
  • Last Modified:
    2015-07-26 21:30:04 UTC