1. Creating a Relational Database
Using Microsoft Access

2. A Relational Database is…..
A database that has more than one table in it

3. The main table has to have…
Each table has to have…..
Fields in it
One of the fields has to be a primary field
The main table has to have…
A unique primary field

4. Each table has to have a relationship to the other tables
This means that some field names in each table need to be the same

5. An example of relationships in a travel company database
We have three tables:
The customerid field is common to both customers and flights – this builds their relationship
The hotelid field is common to both flights and hotels – this builds their relationship
The three tables are therefore linked together

6. The travel ‘relationship’ explained
Any customer can have many hotels and any hotel can have many customers. This is called….
A MANY TO MANY RELATIONSHIP
This relationship cannot be created, so, we need a link table to create these relationships.
This is the FLIGHT table – it ‘delivers’ the customers to the hotels.

7. The travel ‘relationship’ understood
If you have a flight table you can now build:
A ONE TO MANY RELATIONSHIP
Where:
A customer can have many flights, and:-
A hotel can have many customers delivered to it through many flights.

8. Advice for creating your own travel firms relational database
Choose your table headings carefully – always end them with tbl, for example customertbl.
Don’t use more than 3 tables to create your relational database.
Choose your field headings for each table carefully – make sure each table has a primary field that links into another table, for example the customerid is in both the customer table and the flights table.
Make sure that one of your tables has a unique primary field called customer id – and that this field is an automatic number