Records

Computer Science· Unit 10 Data types & structures, 10.3 Records· 15 min read

1. 1. What is a Record?★★☆☆☆⏱ 3 min

📘 Definition

Record (Composite Data Type)

A fixed collection of related data items (called fields) that can be of different data types, used to represent attributes of a single real-world or abstract entity.

Example:

A Student record could have fields for name (string), age (integer), and enrolment status (boolean).

Unlike arrays, which store multiple values of the same type accessed by index, records group heterogeneous data where each field is identified by a unique name. This makes records ideal for modeling structured objects with multiple distinct attributes.

📐 Worked Example

Identify which of the following is best represented as a single record: (A) A list of 100 test scores, (B) The details of a single customer order, (C) A table of 50 employee entries

1
Recall that a single record describes one entity with multiple attributes. Check each option:
2
Option A: All test scores are integers of the same type → best stored as an array, not a single record.
3
Option B: A customer order has multiple attributes of different types: order ID (integer), customer name (string), total cost (float) → matches the definition of a single record.
4
Option C: 50 employee entries → each employee is a record, so this is an array of records, not a single record.
5
Final answer: B

2. 2. Declaring Records in CIE Pseudocode★★★☆☆⏱ 4 min

📘 Definition

Record Declaration

The process of defining a new record type's structure, including the name and data type of each field. Once declared, the record type can be used to create individual instances.

CIE exams follow a standard pseudocode format for declaring records, which you must use to get full marks. The general format is:

\begin{aligned} \text{DECLARE } &\langle\text{RecordName}\rangle \text{ RECORD} \\ &\langle\text{Field1}\rangle : \langle\text{DataType}\rangle \\ &\langle\text{Field2}\rangle : \langle\text{DataType}\rangle \\ &... \\ \text{END RECORD} \end{aligned}

📐 Worked Example

Declare a new record type called Movie with fields: title (string), release year (integer), rating (real), is_available (boolean). Then create an instance called myMovie.

1
Start the record declaration:
2
$DECLARE Movie RECORD$
3
Declare each field with its data type:
4
$title : STRING \\ releaseYear : INTEGER \\ rating : REAL \\ isAvailable : BOOLEAN$
5
Close the declaration and instantiate the record:
6
$END RECORD \\ DECLARE myMovie : Movie$

3. 3. Accessing and Modifying Record Fields★★☆☆☆⏱ 3 min

Fields in a record are accessed using dot notation, which is standard across CIE pseudocode and most programming languages. The format is: $\textit{<record_instance>}.\textit{<field_name>}$ . This notation works for both reading field values and assigning new values.

📐 Worked Example

Using the Movie record type from the previous section, assign values to myMovie and output the title and release year.

1
Assign values to each field using dot notation:
2
$myMovie.title \leftarrow "Inception" \\ myMovie.releaseYear \leftarrow 2010 \\ myMovie.rating \leftarrow 8.8 \\ myMovie.isAvailable \leftarrow TRUE$
3
Read the field values and output them:
4
$OUTPUT myMovie.title + " (" + STRING(myMovie.releaseYear) + ")"$
5
The final output will be: Inception (2010)

✓ Quick check

Test your understanding of dot notation:

What is the correct way to output the rating of the myMovie instance?
- OUTPUT Movie.rating
- OUTPUT myMovie(rating)
- OUTPUT myMovie.rating
- OUTPUT rating.myMovie
Reveal answer
2 —
Correct! Dot notation follows the order instance_name.field_name, you cannot use the record type name to access a field.

4. 4. Arrays of Records★★★☆☆⏱ 5 min

The most common use of records in CIE exams is storing multiple entities of the same type as an array of records. This combines the benefits of arrays (simple iteration over elements) with records (storing heterogeneous attributes per entity). For example, you can store 100 movie entries as an array where each element is a Movie record.

📐 Worked Example

Declare an array of 20 Movie records called cinemaCollection, then output the title of every movie with a rating higher than 8.0.

1
Declare the array after defining the Movie record type:
2
$DECLARE cinemaCollection : ARRAY[1:20] OF Movie$
3
Loop through each element, check the rating field, and output matching titles:
4
$FOR index \leftarrow 1 TO 20 \\ \quad IF cinemaCollection[index].rating > 8.0 THEN \\ \quad \quad OUTPUT cinemaCollection[index].title \\ \quad ENDIF \\ ENDFOR$
5
This loop correctly checks each record in the array and outputs only titles that meet the condition.

5. Common Pitfalls

Wrong move:

Confusing record type with record instance when accessing fields.

Why:

The record type is just a template, only instances store actual data values.

Correct move:

Always use instanceName.fieldName, not typeName.fieldName.

Wrong move:

Forgetting to close a record declaration with END RECORD.

Why:

CIE mark schemes require explicit closing of RECORD blocks to award full marks.

Correct move:

Always add END RECORD after declaring all fields of a record.

Wrong move:

Incorrect dot notation order for fields in arrays of records.

Why:

Students often write arrayName.fieldName[index] instead of the correct order.

Correct move:

Index the array first, then access the field: arrayName[index].fieldName.

Wrong move:

Using a single record to store multiple entities.

Why:

A record is designed to describe one entity. Storing multiple entities in one record makes iteration impossible.

Correct move:

Use an array of records: one record per entity, stored as elements in the array.

6. Quick Reference Cheatsheet

Concept	CIE Pseudocode Format
Declare record type	DECLARE <Name> RECORD <Field>: <Type> END RECORD
Declare record instance	DECLARE <InstanceName>: <RecordName>
Access record field	<Instance>.<FieldName>
Declare array of records	DECLARE <ArrayName>: ARRAY[<low>:<high>] OF <RecordName>
Access field in array of records	<ArrayName>[<index>].<FieldName>

7. Frequently Asked

What is the difference between a record and an array?

An array stores multiple elements of the same data type accessed by index, while a record stores multiple related values of different data types that describe a single entity. Fields in a record are accessed by name, not index.

When this came up on past exams

AI-estimated based on syllabus patterns — cross-check with official past papers for accuracy. Use only as revision-focus signals.

2022 · 12
Declare record for library books
2023 · 11
Process array of student records
2021 · 13
Access nested record fields

Going deeper

syllabusOfficial CIE 9618 SyllabusOfficial syllabus reference for unit 10

What's Next

Records are a foundational composite data type that you will use extensively in both Paper 1 problem solving and Paper 2 programming tasks for CIE A-Level Computer Science. Mastering record declaration and field access is critical for handling structured real-world data, and it builds the foundation for understanding more advanced data structures like linked lists, classes, and relational database entries. You will often encounter records paired with file handling, where you read and write records to text or binary files to store persistent data. Understanding how to iterate over arrays of records is also a common requirement for implementing sorting and searching algorithms, which are core exam topics.