1. Databases
This topic looks at the basic concept of a database, the key features and benefits of a Database Management System (DBMS) and the basic theory behind relational databases such as Microsoft Access. Using Microsoft Access is a good way to get practical experience of relational database concepts and the features of a DBMS.

2. What you need to know…
The OCR Specification says that you should be able to:
describe a database as a persistent organised store of data
explain the use of data handling software to create, maintain and interrogate a database

3. Databases
Many organisations keep large amounts of data. A company stores data about its customers and staff, schools store data about the students, supermarkets store data about stock levels and customer buying patterns. This data could be stored in books, card files or spreadsheets, depending on the volume and type of data.

4. Databases
When there are large quantities of data an organisation is most likely to use a database. A database is described as “a persistent organised store of data”.

5. “A persistent organised store of data”
Store of data Clearly lots of data is being stored in a database. Organised A database is more than just a store of data. A graphics fi le or collection of post-it notes on a wall is a “collection of data”. In a database, the data is organised into records. A school database, for example, will have a record for each student. Persistent This means that a database is a non-volatile store of data on a secondary storage medium such as a hard disk. This is in comparison to an array, which could also be described as an organised store of data but only exists in memory while a program is running. All the data in a database is stored on a disk and can be accessed by programs which use and maintain it (i.e. keep it up to date).

6. Data Handling software
Data handling software can be created using an off-the-shelf product such as Microsoft Access or MySQL. Alternatively you can create the database itself in one of these products and then use a high level programming language such as Delphi or Visual Basic to create a customised, forms-based, front-end application that does exactly what is needed.

7. Data Handling software
A database must first be created. The data must be gathered and organised in some way. Consider a company that wants a database for all its products. They will need a record for each product that holds all the relevant details about that product. The specific details will be stored as fields. Fields for a product database might include ProductID, Description, Supplier, Price, NumberInStock, etc.
We look at the definitions shortly…

8. Data Handling software
A spreadsheet table is a basic database and could look like this: This database contains the basic information that the company needs about product pricing and stock levels.

9. Database
The applications that use this data will interrogate the database. Interrogate means to ask questions about the data or to query it. For example, how many products have a stock level below 50 and need reordering? Or, how much does a bag of humbugs cost?

10. Database
The quality of the information you get from a database application is only as good as the data you put in.
GIGO is an acronym for Garbage In, Garbage Out.
A database must be maintained.
This means that when the data changes in the real world, the database must be updated to make sure the data stored is correct and up-to-date.
A database can be considered in terms of its life history and the operations that can be performed on it:

11. Database
A database can be considered in terms of its life history and the operations that can be performed on it:

12. Key Terms
The following key terms are essential to understand when working with databases. Find out what they mean and record this in your book.
Database
Table
Field
Record
Query
Form

13. Database Theory
Databases are a vital tool in computing. Most websites are based on databases. A database is a collection of DATA A set of data is stored in a TABLE The columns in a table are FIELDS – eg Name, Address, Age The rows in a table are RECORDS – eg information about one person

14. Further Terms
A QUERY is a method of searching through data. A REPORT is a method of publishing the data in a presentable format.

15. Flat file database
A flat file database either contains one table or a few tables that are not linked This is the simplest form of database. However it could be argued that this information may be better stored in other software such as Microsoft Excel.

16. Relational Database
A relational database has a series of linked tables. Each table in a database must have a PRIMARY KEY – this is a unique piece of data which can identify a record – eg Student user ID To connect tables together, another table should have a FOREIGN KEY. This is the primary key from another table and creates a RELATIONSHIP.

17. Example
This example shows a basic Travel Agent database with two tables The TRAVEL AGENT table stores details of each individual travel agent. The TRIPS table contains details of trips booked. The TRIPS table also includes the AGENT ID field from the TRAVEL AGENT table so it records who booked the trip.

18. Another example…

19. Data Types
When setting up fields in a database – you need to tell Microsoft Access what type of data will be stored in that column… Text – Characters (letters, numbers and symbols) Number – Numerical value Autonumber – A number is automatically generated – eg 1, 2, 3 Date/Time – Dates and times Boolean – Yes/No, also known as True/False Currency – Used when dealing with prices/cost

20. Quick Quiz – Name that Data Type
Chuck Norris
1234
14/3/2014
True

21. Introduction to Databases
Queries
Introduction to Databases
It’s not enough to just store data – you need to do something with it. A QUERY allows you to search the database and produce different lists.
Y12 - Applied ICT Unit 2

22. Other types of Criteria
What it means..
Between……. and
Between 1 and 5 G*
Everything beginning with G *A
Everything ending with A
*A*
A in the middle
>5
Greater than 5
<5
Less than 5
>=5
Greater than and equal to 5
<=5
Less than and equal to 5

23. Reports
A REPORT can be created in Microsoft Access It allows you to create a PRINTABLE version of the data from the database This can either be a whole table or the result of a Query