Creating a Database

Designing Structure, Capturing and Presenting Data

What is a database?

Data

Gender: male

Name: Mr James Brown

Salary £30,000

Marital status: single

Blood type: A+

Address: 6 High Street

Telephone: 0170 88691

Name: Mr James Brown

Telephone: 0170 88691

Gender: male

Address: 6 High Street

Blood type: A+

Salary £30,000

Marital status: single

Base

A database is a collection (base) of data that can be accessed as information.

Who uses databases?

Who uses databases?

For the recordBefore computers were around, organizations kept information on record cards in card boxes, or on sheets of paper in files and filing cabinets.

These days, most databases are created and stored on a computer.

Files

J. Vincent

Address: 6 Broad Lane, Winsford

Telephone: 0987 654675

Date of Birth: 02.05.1980

Record

Then…

Filing cabinet

Now…

Database

Files

Record

Records

Fields

Each record is made up of fields – categories of information.

The fields here are Name, Surname, Address, Telephone and Date of birth.

File

Let’s get it right?

Here are some more field names and data types:

Fields are of a certain data type. For example, Name and Surname are text; Date of birth is not text but a date.

Data Types

text date

Using data types ensures that the data in the record is valid.

This means that if you try and type text in a date/time data type the program will not allow it.Mistakes are reduced by making sure the data is valid. However validation would not stop you typing in the wrong date!

Most database programs allow the user to create validation checks, such as the following:

character type (number or letter or both)length of field (how many characters)range (specify from and to, for example from 1 to 20).

Work it out

Use the keyboard to try out the data.

In addition to validating information you must also verify the information.

Not all data can be validated – for example, a spelling mistake or an incorrect amount entered may not be picked up by the validation process.

This is where the data has to be verified.

This is easily done by checking the data entered against the original document, or getting somebody else to ensure that the data being input is correct.

Searching and sortingA database program is extremely useful for searching the data stored.

When you search, you may want to find a particular record: for example, search for the record for “J Vincent”.You can search for more than one record: for example, search for all the records where the field Surname equals (=) Vincent.

For more detail, you can search for records with a combination of fields: for example, search for all the records where the field Surname = Vincent and the Date of birth = 02/02/1980.

Sorting is another useful feature of a database.

When you sort you may want to sort by a particular field, for example, sort by “Name”.

You can sort by more than one field, for example you can sort by field “Name” and field “Surname”.

You can choose which order you would like the sort:ascending order – starting with the letter A or smallest number and going up

or

descending order – starting with the letter Z or largest number and going down.

A database is a collection of information which is stored in a way that can easily be accessed and found.

Databases are used by most organizations to store information.

A database is made up of files.

Each file is made up of records.

Each record is made up of fields.

Fields have a data type.

Data must be validated and verified to avoid mistakes.

A database can be used to search

and sort data.

Summary