2.4 Computational thinking

Computers use 1s and 0s to represent the flow of electricity in their circuits.

A NOT gate takes an input and outputs the opposite.

For an AND gate to give an output of 1, both inputs must be 1.

For an OR gate to give an output of 1, either inputs must be 1.

Stored on the secondary storage Used to store data when application is closed Useful for small volumes od data

Stored in the RAM Used to store data when a program is running Use indexes to refer to data items

Often stored on remote servers Often used to store data shared by man users Data is stored in records and fields

A collection of related fields A field is a variable

Define the record structure Declare a variable or array to use with the record structure Assign and retrieve data from the variable record

To create, delete, modify and manipulate records in a databse

SELECT - which fields to be returned. *can be used to indicate all fields FROM - which table. Databases can have more than one table, each with their own unique name WHERE records meet a condition. LIKE can be used as a wildcard

To ensure there are no errors in the code To check that the program has an acceptable performance To ensure that unauthorised access is prevented To check the program meets the requirements

To ensure there are no errors in the code To check that the program has an acceptable performance To ensure that unauthorised access is prevented To check the program meets the requirements

Each new module is tested as it written Checking new modules does not introduce new errors Test to ensure the program handles erroneous data Performed whilst the software is being developed

Testing that all modules work together Performed when the program is finished