Additional 2.2

Question 1

Records

Answer 1

Unlike arrays, records can store data of different data types.

Each record is made up of information about one person or thing.

Each piece of information in the record is called a field (each row name).

​

Records should have a key field - this is unique data that identifies each record. For example Student ID is a good key field for a record on students as no two students can have the same Student ID

Question 2

what is sql

Answer 2

SQL (structured query language) is a language that can be used to search for data in a database.

Question 3

format of an sql satement

Answer 3

SELECT field1, field2, field3…

FROM table

WHERE criteria

Question 4

in sql what is a wild card

Answer 4

SQL uses wildcards which are symbols used to substitute characters

Question 5

• MEANING IN SQL

Answer 5

The * symbol represents ALL fields.

Question 6

WHAT IS AN ARRAY

Answer 6

An array is a static data structure that can hold a fixed number of data elements. Each data element must be of the same data type i.e. real, integer, string.

The elements in an array are identified by a number that indicates their position in the array. This number is known as the index. The first element in an array always has an index of 0.

​

Question 7

2d ARRAY

Answer 7

The data in a two dimensional array must still all be of the same data type, but can have multiple rows and columns.

Each value in the array is represented by an index still, but now the index has two values. For example [3] [0] is ‘Daphne’. We measure row first, then column.

Question 8

TYPES OF SUB PROGRAMS

Answer 8

Procedures

Carry out a task

Provide structure to code

Functions

Carry out a task AND …

… return a value

Create reusable program components

Question 9

ADVANTAGES OF USING SUB PROGRAMS

Answer 9

The program is easier to write

The program is easier to debug

We are creating reusable components

Functions could be gathered together into a library for easy reuse across multiple programs

An example is import random

This imports the “random” library of functions into our program so we can use them.

The program is easier to test (if we block our program into sub programs, - this is because we can test each procedure or function individually on its own and when we know it works, we can put it into a larger overall program)

Each sub-program can easily be tested

Sub-programs can be saved into libraries and reused in other programs.

Question 10

HOW CAN LARGER PROGRAMS BE DEVELOPED

Answer 10

Larger programs are developed as a set of sub-programs called subroutines

Question 11

advantages of function

Answer 11

Functions return values and create reusable program components

Question 12

advantages of procedures

Answer 12

Procedures create a modular structure to a program making it easier to read

Question 13

Examples of situations where you need to create a program required to generate a random number:

Examples of situations when you might want to generate a random number

Answer 13

Simulating the roll of a dice

Generating a random set of co-ordinates

Gambling simulations

National lottery program

Quiz programs (selection a random question from a list of questions)

Cryptography