Parallel Computing in R

In my work, I usually deal with dataset of products from different customers across different market places. Basically, each product has its own time series dataset. The size of each dataset is not big but we have millions of them. Before finding any convincing reasons to combine dataset from different products, now we just treat them all as independent dataset. And, since they are all independent, it is definitely a good idea to use parallel computing to push the limit of our machine and to make code executed efficiently.

Read More

Connect SQL Server Database to R

When I am working on my personal projects, all the data I have can be easily saved as .csv or .txt files. Things are not complicated. However, when things are in scale, it is hard to not to talk about database. In my company, all the data are stored in SQL Server database. So, it is important for me to know how to connect R with SQL Server. And, also good to know how to interact with database in R by passing variables in R environment to database and then return the desired dataset.

Read More

Learning Microsoft SQL Server

This page is about the SQL Server commands. All of the contents are based on the code in w3schools - SQL with the sample database, Northwind. To make myself easier to look up the commands I want in the future, I picked out the ones I have been used a lot in my work and add some notes on it. I also borrowed some materials from the course LinkdedIn Learning - Microsoft SQL Server 2016: Query Data.

Read More