SQL (Structured query language): a language used for relational database management and data manipulation.
SQL can be read as 'S-Q-L', or 'sequel'.
SQL is a non-procedural language. The reasons can be found from Quora discussions. It's simple, and cannot be used to develop applications, but it's very powerful.
SQL is all about data. It can 1) read/retreive data, 2) write data-add data to a table, and 3) updat data-insert new data.
Microsfot SQL server; MySQL; IBM DB2 Oracle; Sybace ASE; PostgreSQL; SQLite
In the following sections and notebooks, I will use SQLite.
Think before you code, that is important.