​Citation:
http://www.lynda.com/sdk/SQL-tutorials/SQL-Essential-Training/139988-2.html, chapter http://www.lynda.com/home/Player.aspx?lpk4=166252&playChapter=False  (you can access Lynda for free with your Grinnell email account)

Things I learned about SQL:
SQL stands for Structured Query Language. It’s designed to work with Relational Database. 
In a relational database, information is said to be presented in rows and columns. 
A database is a collection of tables, and often other metadata like indexes, triggers, and stored procedures.  
SQL is often used to interact directly with the database often using a vendor supplied interface.
SQL is also commonly embedded in another programming language, allowing the program to manipulate and query the database according to the algorithms of the program itself.

SQL can be divided into 2 major categories:
_DML (Data Manipulation Language): is used to define tables, indexes, and relationships.
_DDL (Data Definition Language): is used to add, query, manipulate, and delete data from tables and datasets