4. A brief history of SQL and its applications

The history of SQL begins roughly 5000 years ago when people started to write down facts in tables – documenting debts, land ownership, etc. The first databases were literally clay tiles:

In the 19th century, the first spreadsheets were created, innovation at a time, a tool that simplified accounting. It was called a spreadsheet because the numbers covered both pages of a spread and acted as one big table. This is where Google Spreadsheet took its name.

With the number of businesses and transactions growing you can imagine how quickly amount of spreadsheet books rose. Since it was all manual labor imagine one would make a mistake after hours of calculations Situation changed with the invention of computers.

In the late 1960s, an idea of the electronic spreadsheet was coined in an article Budgeting Models and System Simulation. Of course, it was just a matter of time going from one electronic spreadsheet to a zoo of spreadsheets that can handle very complex computations replacing slow, error-prone, manual calculations. The first model of using complex spreadsheet logic was described in the 1970’s article A Relational Model of Data for Large Shared Data Banks. As you can see finance played a big role in the development of what we know today as SQL.

In the early 1970s SEQUEL (Structured English Query Language) was developed at IBM, later renamed to SQL (Structured Query Language).

Modern applications of SQL databases

Since 1970s SQL databases have seen exponential progress. Now they power a tremendous amount of Internet websites, apps, companies. Nowadays SQL databases handle insane calculations far beyond accounting. Under the hood though they are still good old spreadsheets or tables with data.

There are 2 main ways SQL databases are employed. First is to use them as production, real-time databases behind websites, apps, etc (for example when you browse through the SQL Habit website it makes SQL queries to show you the table of contents, lessons, and exercises).

Another way is to use the SQL database as a data warehouse, central storage of all data. The main application of this approach – one can ask any question and answer it with data by writing an SQL query.

In the SQL Habit course, we’ll explore the latter approach, by writing queries to Bindle’s data warehouse.