Databases

Databases are probably the most important software in the world. They run everything from transport networks and company systems to the internet. This unit was interesting to me because first of all we learned about the features and functions they can have. The presentation above covers that – and I got very interested in them.  There are some notes about this presentation below this section.

Before I had just used tables I was given but now I could design my own.

We went through the whole design process of a database but the thing that really interested me was the validation of the tables. Validation is included to make sure that people don’t make too many mistakes.

You use the code in the design of the table and put in a message which the user sees if they type anything wrong. I put a lot of these in to my database, including the ones below.

• A validation code of >.99 to tell users that all the movies cost more than that in the shop. 
• A validation code of 1 Or 2 Or 3 Or 4 Or 5 to tell the user that the films only have 5 ratings 
• A validation code of Is Not Null to tell the user they need to add a customer name in a new customer record. 

If they type in the wrong thing the user will get one these messages that I set up.

There are so many it is great because you can make it so that users will find it very difficult to make mistakes. My favourite was ‘is not null’ because it’s great to just remind people that they have to type something in to a field and they can’t move on until they do. I find this part of the design really interesting. I am now thinking about work in the future – maybe in the software validation side of IT.

LEARNING AIMS IN BRIEF

In this unit I learned how to:

• understand the uses of and tools/techniques used in databases
• design a relational database
• develop and test a relational database
• review the finished relational database.

Further notes on the presentation above
The first assignment was done as a PowerPoint presentation discussing the purpose, tools and techniques of databases. It also talks about the advantages and disadvantages of two different databases and how both of them improves accuracy, productivity and usabilty. It also covers the following key parts:

• Introduction
• Purpose of the database 
• Table structures
• Field characteristics
• Primary key tool
• Validation rules 
• Indexes 
• Records
• Relationships
• Using forms and queries in the database 
• Advantages and disadvantages of both database