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CS Professional · Artificial Intelligence, Data Analytics and Cyber Security - Laws and Practice · Information Systems

A firm's database records an employee's department name and department head in every employee row, so changing a department head means editing hundreds of rows and some rows end up inconsistent. Which design step best removes this problem?

Normalisation is the right step. Moving department name and head into a separate table linked by a key stores each fact once, removing redundancy and update anomalies, whereas encryption, backups or denormalising do not cure inconsistent duplicated data.

  1. ADenormalising the table to add more columns
  2. BNormalising by moving department details into a separate table linked by a keyCorrect
  3. CEncrypting the department head column
  4. DCreating a backup of the employee table daily

Explanation

The problem is an update anomaly caused by redundant data. Normalisation separates department data into its own table, so the head is stored once and linked by a key. Denormalising increases redundancy, while encryption and backups do not remove inconsistency.

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