levo
Log inStart

Data Structures

Records and fields

  • 3 things to know
  • AS Unit 1

Overview

Key field and record type definition.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Key term

Give a suitable record structure for a book in a library system.

Key term

Why is a record better than several parallel arrays for describing one entity?

Key term

How does a record differ from an array?

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Define a record.

    Model answer

    A record is a composite data structure that groups several related items, called fields, under one identifier, and those fields may each be of a different data type.

  2. 2

    How does a record differ from an array?

    Model answer

    An array holds many items of one single type reached by their position, while a record holds a fixed set of named items that may each be of a different type.

  3. 3

    Give a suitable record structure for a book in a library system.

    Model answer

    It could hold a catalogue number as a string, a title as a string, an author as a string, the year of publication as an integer and a flag as a Boolean showing whether it is out on loan.

  4. 4

    How is one field of a record referred to in a program?

    Model answer

    By naming the record variable and the field, usually separated by a full stop, as in book.title.

  5. 5

    What is a key field?

    Model answer

    A key field is one whose value identifies a single record uniquely within the collection, such as a membership number.

  6. 6

    Why must a key be a value that neither repeats nor changes?

    Model answer

    If two records could share it the wrong one might be retrieved, and if it could change the record could no longer be found by the value already recorded elsewhere.

See the rest and revise

Other ways to work this

The same content, four other ways.

What is inside Levo

Six ways to work the same material.

1Closed book
2Open book
3Closed book

The 3-step method, run for you

Answer cold, learn it, then prove it stuck. Levo tracks the jump between your first attempt and your last.

Hardware: Architecture, Memory and Storage
Networks and Data Transmission
Logic Gates and Boolean Algebra
Data Representation and Data Types

Cram a whole paper in one sitting

Sort every topic into what you know and what you do not, then drill only the weak ones.

Fetch, , execute.
decodecompilestore

Blank Blitz makes facts automatic

Rapid timed gap-fills on the terms and numbers you need to recall without thinking.

AEncryption is reversible.
BThe stored form could be decrypted.
CA hash cannot be reversed.

Build It gets the exam shape right

Assemble a full-mark answer from its marking points, in the order an examiner wants them.

A bit is a single binary digit.
TrueFalse

Test It catches misconceptions

Spot the fault in a statement. The traps are the mistakes students actually make.

721941163128510

Brain Breaks between sessions

Short focus games to reset attention, so the next set lands better than the last.

Every question in Data Structures, on a schedule.

Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.

Start revising, £5 a monthSee how the method works

Or £46 a year, about £3.83 a month. Cancel anytime.