SQL [- and for that matter databases!] is something I’ve heard about, but hadn’t really looked into before today [I knew it was coming up in the Odin Project curriculum, so I thought I’d just wait until I got to that part of the course.]
The databases page of the Odin Project points to one of my favourite online learning resources; Stanford Online. I have a lot of time for online courses like that, not only are they a great way to learn, but they’re extremely accessible for people like me, who are working full time and can’t a lot of time out from work, or afford to go to college or university full time.
One of the main things I’ve been learning about had been relational databases. As far as I understand, relational databases are the most efficient way to store large amounts of data, and make use of multiple tables, which are related. That way you can access data from one table inside of another. I found a really great example [I thought, anyway] that used a libraries databases [that is, an actual library- one filled with books!] A library would need a database to keep track of books in the collection, as well as to keep track of library members. This would be done using separate tables- one for books containing the details of each book in the collection [title, author, subject, reference number, and whether or not the book is currently available,] and another table with all of the member’s details. When the book has been checked out its status can be updated to say that it’s not currently available, and can also reference the borrowers’ ID number [library card number], which can be used to access the rest of the borrower’s information. You would also be able to access the details of the books borrowed by looking up a member of the library. [Of course, you wouldn’t be able to do this as a member of the public! This is just an example of the structure.]
A lot of what I’ve been learning has seemed like common sense, so it doesn’t feel like I’ve learned that much, but I suppose I should consider that a good thing!