A3.1 Database fundamentals: notes and practice

What you need to know

Our summary of the topic in our own words, not the IB guide.

• Explain what a database is and how it differs from a flat file or spreadsheet
• Define table, record, field, entity and attribute in relational terms
• Explain what a primary key is and why every table needs one
• Explain what a foreign key is and how it links two tables
• Explain what a composite key is and when one is needed
• Identify one-to-one, one-to-many and many-to-many relationships in a scenario
• State the benefits of a relational database including reduced redundancy, consistency, concurrent access and access control
• State the limitations of a relational database including rigid schema, design cost, and difficulty with unstructured data and very large scale
• Describe the data anomalies that poor design causes on insert, update and delete

Practice questions

Original questions written for the 2027 course, marked as you go. Easiest first.

• Database relationships for a bike-share schemeWritten · Core
• Primary and foreign keys in a library databaseWritten · Core
• Database anomalies in a drama club tableWritten · Stretch
• Keys and relationships in bike-share trip dataWritten · Stretch

Exam tips for A3.1

• Define primary and foreign keys precisely, and say which table each key lives in.
• Use a small example when explaining an update or delete anomaly. It makes the point clear in a few lines.
• Spot one-to-many relationships by asking "can one of these have many of those?" in both directions.