AS LEVEL IT

Data

String of raw text

Information

Data that has been given context and has a meaning

Knowledge

The possession of information and facts by a person which requires understanding

Direct data sources

Data is collected first hand for a certain purpose. Eg: Questionnaires

Indirect data sources

Data is collected from a secondary source

Static data

Data that does not change

Dynamic data

Data that changes automatically without user intervention

Coding

Representing data by assesing a code

Encryption

The scrambling of data so that it cannot be understood by unauthorized third parties.

Symmetric encryption

A method of encryption where the same public key is used to encrypt and decrypt data.

Asymmetric encryption

A method of encryption where a public key is used to encrypt data and a private key is used to decrypt data.

Validation

Checking data follows a specified rule

Verification

Ensuring data entered into the system matches the original source

Batch processing

Sets of data processed all together without user interference

Master file

Table in a database consisting of information about a set of things

Transactional file

Data that is used to update a master file

Online processing

Interactive processing

Real-time processing

Data is processed once it is inputted and an output is received immediately

System software

Software needed to operate a computer system

Operating system

Software that operates a computer's hardware

Device drivers

Software that comes with external hardware components sends customized instructions to the component

utilities

Programs that maintain a computer system

Linkers

Combine multiple object code into a single executable program

Sensors

Input device collecting data from the physical environment

Calibration

Testing and adjusting a device to make sure it takes the correct reading

Mainframe computers

Computers serving several terminals

Supercomputers

Large computers with parallel processing to complete complex tasks quickly

Database

A structured method of storing data (in set of tables)

Table (Database)

Collection of related data

Flat File

Database stored in single table

Entity/Record (Database)

Table in a Database/Set of data about one thing (person

Attribute/Field (Database)

Category of information in an entity/Column in table

Primary key

Field containing the unique identifier for a record

Database Management System (DBMS)

Software used to manage database

Relationship (Database)

The way in which two entities in two different tables are connected

Foreign key

Field in a table that refers to the primary key in another table

Normal Form

Extent to which a database has been normalized/Stages of normalization (0NF

Entity Relationship Diagram (ERD)

Diagram that represents relationships between entities

Index

List of keys or keywords which identify a unique record and can be used to search and sort records more quickly

Compound key

Two or more fields that form the primary key

each field being keys from another table

Referential Integrity

Data in the foreign key of the table on the many side of relationship must exist in the primary key of the table on the one side of a relationship

Query

Question used to retrieve data from database

Parameter

Data used in criteria for a query

Normalisation

Process of structuring data in database

Data Dictionary

Metadata (information) about database