My First ERD (Entity Relationship Diagram) and Learning SQL

For work I run the software platform we use to create and store our process documentation. The data is stored in a database server. The database logs changes/transactions and in order to pull some data out of the database for reporting and for other uses, we use SQL (structured query language). ("We" as in mostly the IT folks I work with. But I'm learning!)

As I learn more about databases, I drew this Entity Relationship Diagram (ERD) for a university setting. An ERD is a way to map out the relationships between various tables that make up the database. My diagram is super simple and it has some mistakes, but I wanted to share my first attempt here for comments, critique, etc. in the hopes of learning even more.

Here's a link to the ERD I drew using a tool called Lucidchart. I suppose you could use Gliffy, Visio, or a dozen other tools. (By the way, since I'm new at this, what are some of the most popular tools folks in the know use to draw ERDs?) Here's a video tutorial about ERDs produced by Lucidchart.

As for SQL, I find it very interesting. I completed all 52 exercises at w3schools and also had to run a bunch of SQL scripts using Microsoft SQL Server Management Studio for an assignment for my Web Analytics course with Boston University.