Standard GradeDatabases

What is a Database?

• A database is made up of files, records and fields.

• A structured collection of similar information that can be searched and sorted.

What is a Database?

• A database can be stored on paper (manual) or on a computer (electronic).

• A program that is used for organising data on a computer is called a database package.

• Data is organised in a database as files, records and fields:

• A database is an organised, structured collection of similar information.

Files

A file is a collection of records.

Data in a database is saved on the computer as a data file and contains data on a particular topice.g. a Films data file.

Records

A record is a collection of fields.

A record is a collection of organised data on a particular person or item.

Fields

A field is a single item of information.

A field is part of a record that holds a particular piece of data e.g. Surname.

Files….Records…Fields?

Field

Record

Here is a sample record from a telephone directory data file made up of different fields:

Mr.

Title Forename Postcode Tel. No.

John Smith 101High Street

Ayr KA7 3KL 01292 262626

Sample Fields

AddressSurname Town

• Databases are used by many types of business and organisations such as:

• Telephone Directory

• Police National Computer

• Inland Revenue

• Driver and Vehicle Licensing Centre

•   A personal Christmas card list

• A mailing list

• Data held in a database can be shared between other computer packages such as a word processor package – e.g. Mail Merge.

What is a Database used for?

• Records can be processed quickly.

• Records can be processed accurately.

• Information is immediately available.

All of this is impossible in a manual system !!!!

Advantages of an electronic database?

• Databases have many of the features common to a general purpose package.

• There are some special features of a database:• Create fields

• Add and alter records

• Search

• Sort

Features of a Database?

• The first step on setting up a database is deciding on the fields it requires.

• Fields hold the information you want to store.

• You can set the size and type of a field.

• Size: You can decide how many characters a field can hold e.g. a Postcode field to hold KA18 3GH would require a minimum of 8 characters as the space counts as a character!

• Type: Fields can hold different types of data:• A text field holds letters.• A number field holds only numbers.• Date and time fields hold numbers formatted into date and time.

Create Fields

• The next step is to enter records into the empty database. A new record has to

be created for each item. e.g.

Mr John Smith 1 Anytown Scotland 01929 393939

Mrs Susan Jones 5 The Town Scotland 01521 447210

Add and Alter Records

Record 1

Record 2

e.g. search for the forenames and surnames of people whose test mark was greater than 50.

• You can run a search on a database for specific information.

• You can search on a field (or fields) based on certain conditions you require.

Search Records

     

• Sorting allows you to organise records into a particular order:

• alphabetic•   numeric

• ascending (1,2,3,4,5…)• descending (Z, Y, X, W …)

• The sort is done by choosing which field the database is to be sorted into e.g. sort alphabetically by surname.

Sort Records

Reports

• any information printed out from a database is a report.

• you can search for information, then sort it into an order, and decide what fields you wish printed out in what order.

• this is known as a report definition.

Additional features of a Database

Example:

If a database has the fields <Total Pay> and <Total Deductions>, then a third called <Net Pay> could be set up with the formula:(=Total Pay – Total Deductions).

This is a computed field.

• A computed field (also called a calculated field) can be created in a database or report.

• It carries out a calculation on a field or fields and returns an answer (similar to a spreadsheet formula in a cell).

Computed Fields

• You can decide how the information in your database is presented by altering the

format. • You can change the way the input screen looks and format a report for output.

• The position of fields can be rearranged and formatted into a particular order and layout.

• This is useful for designing input screens and producing documents such as invoices for output.

Altering Input/Output formats

Use of Keywords

• When searching for a particular record or part of it, the text that is used for the search is called a keyword.

• It is also known as a search string.

• However, care must be taken that the correct keywords are used.

Keywords