• Leistungsnachweis:
  • 80% praktika teilnehmen & aufgaben losen
  • 1 praxisaufgabe lösen+abgeben >=50%

Sub-queries

/L “AND bindet stärker als OR”

INSERT/UPDATE/DELETE

In INSERT INTO relationName [(columnName1, ..., columnNamek)] VALUES (v1, ..., vn), adding column names is optional but helps a lot with readability.

TODO - insert into multiple rows VS batch insert

• s. 1/55

• Functional dependencies:

  • title, year, actorID -> role
  • actorID -> firstName, lastName etc.

• re. /D Database Normalization

  • process of structuring a relationaldatabase

• “give me the functional dependency between …”

• transitive dependencies

• TODO primary key

• Modellierungsprozess

• Needed when designing the table, if done formally you can have fewer redundancies and problems

• TODO Partial dependency VS total dependency

• Functional dependency if all keys in X define Y

  • X -> Y != Y -> X
  • X can have multiple values of Y, this is okay if X->Y

• You can derive rules based on existing ones

• Normal forms

  • Formal criteria about lack of redundancy

Big data challenges

• 5 Vs:
  • Volume
    • A lot
  • Velocity
    • A lot of data generated quickly
    • Data analysis while it’s still being generated
  • Variety
    • Different and unstructured
  • Veracity
    • Glaubigkeit der Daten
    • Different sources, standardization, accuracies, abbreviations
    • Some are derived from others, etc.
  • Value
    • All data is useless unless you turn it into value (=useful information)