Learning SQL – Part 1

Sql stands for Structured Query Language and is being used to query and manipulate relational databases. Most of the Relational Database Management Systems use SQL as standard database language. I will be using MS SQL in these examples and learning process.

Sql History

Dr Edgar F. Codd is known as the “Codd Father” of the relational databases. He described a relational model for databases in 1970. First SQL appeared in 1974 and IBM has worked to develop the ideas of Codd and released a product System/R. In 1986, IBM developed first prototype of relational database and it was standardized by ANSI.

SELECT statements

Capabilities of SELECT statements

SELECT statements can give us a projection, we can get a subset of a column. Secondly, you can filter the number of rows with SELECT and also you can join different tables by primary and foreign keys. It allows to get data from different tables and show as a table.

Basis SELECT statement identifies the columns o be displayed and you also need to add FROM to tell which tables you will get the data from. Read more “Learning SQL – Part 1”

Secret of the Name “AshleyMadison.com”

So after a few weeks of Data Management and Analytics class and having been working on with R, I have attended to the DBS Analytics Society meeting on 22nd of October.

Thanks to Darren, we had some pastries for breakfast, eating them while drinking a double shot coffee woke me up on a Saturday morning.

Darren prepared us four different quizzes although I could have finished only two of them in 2 hours, it was a very helpful meeting to practice R with different data sets.

First quiz was about basic R commands and how to use them. It was relatively easier than the second quiz. I have uploaded my code to my Github account with the questions. I got one mistake in my first trial as first question was asking for sum of the output where I gave the output as the answer.

Read more “Secret of the Name “AshleyMadison.com””

People, People Everywhere!

Being from a country where we had five elections/referendums in last 5 years, I have seen many different maps with the election results and I always wondered how they created those maps. I saw my first Fusion Table based map when Panama Papers hit the news. This map shows all the addresses from Ireland which were mentioned in Panama Papers and I remember admiring how quickly Gavin Sheridan created that map, literally 10 minutes after his first tweet about the addresses.

Although I was impressed with an efficient tool such as Fusion Tables, I haven’t used it until this year. My first attempt to create a map from a Fusion Table was during our Application of Cloud Technologies module, just a week before Data Management & Analytics class. It was a good preparation for Data Management & Analytics class and for this assignment. During the class, we have created a US Population Density Map and were asked to do a similar version of that map for Ireland.

To create the Irish Population Density map, I was given two different data and we have been asked to turn them into information. The first data set was from Central Statistics Office (CSO) website. 2011 Census population data was enough to get the population by county and gender. I have done a bit of cleansing, by removing break down of city data for big cities and get every county in one lane. Dublin, Cork, Galway, Waterford, and Limerick population were given by county and by City and County. I have removed those lines and I also added South Tipperary and North Tipperary data to one line. Also after uploading my KML file, I have realized that Laoighis was spelled differently in KML data, so I have changed that in my Fusion table into to Laois.

Read more “People, People Everywhere!”