Wednesday, 15 May 2013

My general presentation on databases for newbies

Hello everyone. My name is Adam. I’m a computer scientist and a specialist in databases. Today, I’ll speak to you about databases. I divided my presentation into 3 main sections:

First, I’ll give you a brief overview of the world of databases.
Secondly, I’ll tell more about different types of databases, including NoSQL databases.
At the end I’ll sum up the presentation and tell you about a special particle.

I’ll try to leave time for questions at the end.

So let me explain you the basics. Generally, databases are used to store and process data. The data is typically organized to model relevant aspects of reality. We can encounter databases everywhere. The exemplars of databases can be found in banks, where a large amount of data are stored and processed. The data about the balance on my account, about transactions and many other things have to be stored. The information about products in shops is stored in databases. What’s more? You can find databases even in your smartphones! Be aware that databases are in all kinds of devices. Outside the world of professional IT, the term database is sometimes used casually to refer to any collection of data, perhaps a spreadsheet in Excel.

There are at least 5 main kinds of databases.
- relational databases - represent a traditional approach to databases where data are stored in tables (the tables similar to that you know from Excel spreadsheet)
- object oriented databases - data are stored in objects. Nowadays, to write programs we use mainly object oriented programming and object databases’ main purpose is to make it easier to store data from objects in applications to objects in databases.
- NoSQL databases - these databases are used to store huge amount of data and are used mainly by companies, such as Facebook, Google, Amazon and even CERN.
- graph databases - the basic model is a graph with nodes and edges. This kind of databases suits best for modelling connections between elements, for example, what are the all railway connections is Poland
- hierarchical databases  - to model hierarchy of elements, for example, a hierarchy of people in an organisation.
- spatial databases - the queries on such data include location based queries, like "Where is the closest hotel in my area?".

Nowadays, there are many information systems that store data in databases. Databases were created to provide us with tools to store data efficiently and they cause that processing data is not burdensome anymore. The interesting thing is that after almost 40 years of reign of relational databases, which is something unusual in fast developing technology field, new movement of NoSQL databases emerged. I brought to you the particle of NoSQL databases from CERN.

Thank you. Are there any questions or comments?

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