Checking Your Work (Quality Control)

• Look for one-to-many relationships.

  • Many side should be keyed (underlined).
  • e.g., VideosRented(TransID, VideoID, . . .).
  • Check each column and ask if it should be 1 : 1 or 1: M.
  • If add a key, renormalize.

• Verify no repeating sections (1NF)

• Check 3NF

  • Check each column and ask:
  • Does it depend on the whole key and nothing but the key?

• Verify that the tables can be reconnected (joined) to form the original tables (draw lines).

• Each table represents one object.

• Enter sample data--look for replication.

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