Video summary

Perancangan Basis Data

Main summary

Key takeaways

Educational

Main ideas & concepts

  • The video continues Case Study 3 focused on database normalization, specifically designing the First Normal Form (1NF).
  • The goal of 1NF is to ensure that:
    • Each attribute value is atomic/single (no repeating or multi-value fields).
    • The relation’s key/primary attributes are chosen so records can be uniquely identified.
    • Unnecessary attributes that cause data redundancy are removed—especially attributes derived from other fields.

Methodology / steps for 1NF (detailed)

Step 1: Ensure atomic (single) values

  • Check whether any fields contain empty/missing data or multi-value (non-atomic) data.
  • If there is empty data in the normalization table, fill it using the universal/source table.
  • After filling, verify there is no multi-value data remaining:
    • Each attribute should correspond to a single value per row.

Step 2: Choose required key attributes (primary candidate)

  • Identify attributes that could serve as a primary key candidate.
  • Examples used:
    • Invoice number
      • Must be unique, because each invoice/note has a different invoice number.
    • Buyer’s name
      • Cannot be the primary key because multiple people can share the same name.
      • Therefore, replace/augment it with a unique identifier:
        • Add Buyer ID (buyer/consumer code).
    • Item code
      • Treated as unique because each item has its own item code.
    • Cashier’s name
      • Not unique if multiple cashiers share names.
      • Therefore add a unique identifier:
        • Cashier ID.
  • Resulting key structure (as described):
    • Primary candidate attributes include invoice number and item code,
    • plus supporting IDs such as Buyer ID and Cashier ID.

Step 3: Remove attributes that cause redundancy

  • Identify attributes whose values are derived/calculated from other fields (not dependent on the primary key).
  • Examples removed:
    • Total price
      • Calculated from: number of items × unit price
      • Since it can be computed later, it is not stored in the normalized table.
    • Remaining payment
      • Calculated from: total price − DP (DP likely a down payment)
      • Since it is also derivable, it is removed to avoid redundancy.
  • The video notes that these removed values can be obtained later using query syntax (SQL/DML).

Step 4: Produce the final 1NF table

  • The final table is described as containing:
    • Proper atomic values (no multi-value fields),
    • IDs added to guarantee uniqueness (Buyer ID, Cashier ID),
    • Redundant derived fields removed (e.g., total price, remaining payment).
  • After 1NF is achieved, the video states it will proceed to 2NF normalization next.

Speakers / sources featured

  • Tabibun (speaker addressing viewers; mentions “in this session we will continue…”)

Original video