Practice Flashcards
Flip to reveal answersWhat is a relational database?
Track your progress — Sign up free to save your progress and get smart review reminders based on spaced repetition.
All 5 Flashcards — Relational databases
Sign up free to track progress and get spaced-repetition review schedules.
Question
What is a relational database?
Answer
A database that stores data in tables and links those tables together with keys, so each fact is stored once in the table it belongs to and other tables point at it rather than copying it.
Question
What is the difference between a primary key, a composite key and a foreign key?
Answer
A primary key uniquely identifies each row in its table. A composite key does that using two or more columns together, when no single column is unique. A foreign key holds a primary key value from another table, which is how the link is made.
Question
Give three benefits of a relational database.
Answer
Reduced duplication, because each fact is stored once; data integrity, because the database enforces rules such as refusing an invalid foreign key; and consistency, because changing a fact in one place is seen by everyone.
Question
Give three limitations of a relational database.
Answer
A rigid schema that must be decided up front and is disruptive to change; poor handling of unstructured data such as documents and images; and difficulty scaling very large volumes across many machines.
Question
Why is storing everything in one large table a problem?
Answer
The same fact gets written out on every row that mentions it. Changing it means finding every copy, and missing one leaves the data contradicting itself.
Read the notes
Full study notes for Relational databases
Topic 3.1 hub
Database fundamentals
More from Topic 3.1
All flashcards in this topic
Computer Science exam skills
Paper structures & tips
Track your progress with spaced repetition
Sign up free — Aimnova tells you exactly which cards to review and when, so you remember everything before your IB exam.
Start Free