AQA GCSE Computer Science key terms

Unnecessary duplication of the same data within a database.

A way of organising and storing data in a computer so that a program can access and work with it.

The kind of data a field can hold, such as string, integer, real, date/time or Boolean.

An automatic check that entered data meets specified rules before a program uses it.

The process of finding and correcting errors in a program.

The base-10 number system, using the digits 0–9.

A prefix indicating a power-of-ten multiple of a unit. For byte quantities, each step from kB to MB to GB to TB represents 1000 times as many bytes.

A statement that introduces a named variable or constant; some languages also require its data type to be stated.

Breaking a problem into smaller sub-problems that can be solved separately.

A preset password supplied with a device, system or account, which may be known to attackers if left unchanged.

Repetition controlled by a specified count or range, so the number of repetitions is determined in advance.

The process of rearranging fragmented files on a hard disk so that the parts of each file are stored together.

An SQL command that removes rows from a table.

An ordering from largest to smallest for numbers, or Z to A for text.

Software that allows an operating system to communicate with and control a hardware device.

A representation of information using separate, distinct values rather than a continuously varying signal.

The inequality between people who can access and use digital technology and those who cannot.

An approach that breaks a problem into smaller problems, solves them and combines their results.

Accessing a named field by writing the record variable's name, a dot and the field name, for example myCar.model.

The length of time covered by a sound recording, measured in seconds for sound file size calculations.

An individual item stored in an array.

A check in which a user follows a link or enters a code sent to an email address to demonstrate access to that email account.

A computer system built into a larger device to perform a dedicated function.

A table showing which code represents each character in a character encoding.

The conversion of readable data into scrambled data using an algorithm and a key, so it cannot be understood without the appropriate decryption key.

An effect on the natural environment, such as resource use, energy consumption, pollution or waste.

Input that breaks the specified rules and should be rejected, such as an out-of-range value or an unsuitable data type.