Topic 8-Information Handeling Software (data bases)

Any software used to store, manipulate and output information

Covers:

• Database software
• Database created using spreadsheets software
• Stores of music, sounds, photographs

Paper Based Databases

• A database is a collection of data or information which is held together in an organised of logical way

Tables

There are a few terms that you need to understand when learning about databses.

• Databases store data or information in tables
• Tables allow you to see all of the records stores on the database. Tables can store many records, from a few dozen for a small database up to millions for a large company database.

Records

• Each table can contain a lot of records
• DEFINITION: A record is all of the data or information about one person or one thing

Fields

• Each table contains a lot of records
• A record is made up of lots of individual pieces of information
• Each of these individual pieces of information in a record is called a "field"

• DEFINITION: A "field" is one piece of data of information about a person or thing

Data types

• Alphanumeric or Text
• Number
• Currency
• Date/Time
• Auto Number
• Logical, Boolean, Yes/No

Logical, Boolean, Yes/No

• This data type can be known by any of the names above
• All it means is that the data is restricted to the of only two choices, e.g.
• Yes/No
• Male/Female

• Hot/Cold
• On/Off

Primary Key/ Key field

• This question is asked every year
• State the purpose of the key field in a database table
• It is a field used to uniquely identify a record from within a table
• The questions may ask you to identify a primary jet or unique identifier from within a table provided
• This will nearly always be a customer/membership number or item number

Validiation

• As well as choosing the correct data types to try to reduce the number of errors made when entering data into the database, there is another method that can be used when setting up the table. This is called "Validation"

• It is very important to remember that Validation cannont stop the wrong data being entered, you can still enter "Smiht" instead of "Smith"
• What Validation can do, is to check that the data is sensible, reasonable and allowable

Validation Techniques

• Type Check
• Range Check
• Presence Check
• Picture or Format Check

Verification

• Verification means to check that data that you have entered against the original source data

Data Queries

• Databases are extremely good at storing data or information. However, they are only any use if we can find specific information from them
• Searching the database to find specific information is known as a query

Encoding Data

• As data input can sometimes be a laborious job, a technique known as encoding can take place. This involves putting data into a shorter format e.g. Female would become "F", male would become "M"
• This is done for a number of reasons
• Uses less storage space
• It is easier to then validate
• Its faster to input
• You can see more data on the screen

Advantages of keeping data on a computer

• There are many advantages to keeping data stored on a computer rather than on a paper based format

Advantages:

• Faster/ easier to update, for example membership details
• Can create a variety of output reports i.e. a graph
• Faster. easier to search for clients, for example a particual customer number
• Faster/ easier to sort the data, i.e. alphabetically
• Can mail merge letters to a large number of customers
• Can use validation techniques to check data that is entered
• When talking about these advantages you must give the advantage and a good example to illustrate what you are trying to say