Up until a few years ago, companies were only storing data that was important to them and directly linked either with their business or customers. These types of data are mostly structural in form, which means that each of the data records in the dataset available will have similar attributes. In most cases, they are also linked together and have different types of relationship between them.
There are many commercial and open source relational databases available in the market that help us to store and manipulate structural data. Example of these databases are MySQL, Microsoft SQL, and PostgreSQL. Some of them are free to use for both individual or commercial use, but some of them require licenses. The license cost varies ...
