Additional Programming Techniques: Producing robust programs: Computer Science: GCSE (9:1)

Array

A data structure that stores many data items of the same data type, can be 1D, 2D or more. In Python we use a list for this

gameboard[0,0]

The pseudocode in Exam Reference Language (ERL) to return the contents of row 0 column 0 of a 2D array called gameboard

Record

A collection of related data items called fields, often stored as a row in a database, it represents something in the real world like a person or product

Field

A data item in a record, often shown as a column in a database. For example "Name" or "Age". It has a single data type

Slicing

Dividing up a string into parts. In ERL we use the Substring method, in Python we use string[a:b]

Concatenation

Joining two strings together, usually uses the + operator, for example fullname = firstname + lastname

"Char"

The string returned by this code:

phrase = "Character"

phrase.subString(0,4)

Substring

A function in Exam Reference Language (ERL) that returns part of a string when we pass it a starting position and length

File

A collection of related data saved on secondary storage, it can be plain text, CSV or a database

Open

Connect to a file and prepare it for read or write with a command like this (ERL):

myFile = open("sample.txt")

Close

When finished reading or writing this makes the file available to other programs, this is the command (ERL):

myFile.close()

Read

Load data from an open file into a variable or data structure in memory. Example command (in ERL):

myFile.readLine()

Write

Add data to an open file from variables or data structures in memory. For example (ERL):

myFile.writeLine("Add new line")

SQL

Code that is used to query a database, it stands for Structured Query Language and includes SELECT, FROM, WHERE

SELECT

The SQL command used to view or query a database

FROM

The SQL keyword that specifies the table to be queried

WHERE

Keyword that specifies the criteria to select upon, in an SQL query

"Cher"

The result of the following query on the this database table

SELECT Name FROM Students WHERE House = "Curie" AND Grade = "B"