Fundamentals of Databases | AQA A-Level Computer Science (7517)

Fundamentals of Databases

69 questions
5 subtopics
Paper 2: the written exam
Paper 2

Entity relationship modelling, relational databases and their keys, normalisation to third normal form, SQL, and managing concurrent access in a client server database.

Examined on Paper 2.

Sample questions from Fundamentals of Databases

Answer each one closed book first, then open the answer.

Conceptual data models and entity relationship modelling

In what form is an entity description written?

Show the answer
As the entity name followed by its attributes in brackets, separated by commas: Entity1(Attribute1, Attribute2, ...). For example Book(ISBN, Title, AuthorID, Publisher, YearPublished).
Relational databases

Define the term attribute.

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An attribute is a named characteristic or property of an entity — one item of data recorded about it, such as Surname or DateOfBirth. In an implemented relational database an attribute corresponds to a column of a table, and every row has one atomic value for it.
Database design and normalisation techniques

What must be true for a relation to be in third normal form?

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It must already be in second normal form, and it must contain no transitive dependencies — no non-key attribute may depend on another non-key attribute. Every non-key attribute must be determined by the primary key directly, and not by way of some other ordinary attribute.
Structured Query Language (SQL)

Write SQL to delete all loan records that were returned before 1 January 2020, from Loan(LoanID, BookID, MemberID, DateOut, DateReturned).

Show the answer
DELETE FROM Loan WHERE DateReturned < '2020-01-01'; DELETE FROM names the table and WHERE selects which records go. Note that DELETE removes whole records only — there is no way to delete a single attribute value with it; setting one attribute to nothing is an UPDATE.
Client server databases

Name the four methods used to manage the problem of concurrent access.

Show the answer
Record locks, serialisation, timestamp ordering and commitment ordering.

The 5 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
Conceptual data models and entity relationship modelling	Recall questions on entities and their occurrences, the three degrees of relationship, and resolving a many-to-many relationship with a link entity.	13
Relational databases	Recall questions on attributes, primary, composite and foreign keys, which table carries the foreign key in a one-to-many relationship, and referential integrity.	12
Database design and normalisation techniques	Recall questions on why databases are normalised, the conditions for first, second and third normal form, functional dependency, and normalising a given table.	15
Structured Query Language (SQL)	Recall questions on SELECT, FROM, WHERE and ORDER BY, joining tables on their keys, LIKE and its wildcards, and writing INSERT, UPDATE and DELETE statements.	17
Client server databases	Recall questions on why concurrent access threatens integrity, the lost update problem, and record locking, serialisation, timestamp ordering and commitment ordering.	12

Fundamentals of Databases is 69 of the 1,516 questions in the guide.Get the guide, £9

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.