I'm trying to optimize my site and found this nice little Django doc: Database Access Optimization, which suggests profiling followed by indexing and the selection of proper fields as the starting point for database optimization.
Normally, the django docs explain things pretty well, even things that more experienced programmers might consider "obvious". Not so in this case. After no explanation of indexing, the doc goes on to say:
We will assume you have done the obvious things above.
Uhhh. Wait! What the heck is indexing?
Obviously I can figure out what indexing is via google, my question is: what is it that I need to know as far as database stuff goes in order to create a scalable website? What should I be aware of about the Django framework specifically? What other "obvious" things ought I know? Where can I learn them?
I'm looking to get pointed in a direction here. I don't need to learn anything and everything about SQL, I just want to be informed enough to build my app the right way.
Thanks in advance!
I encourage you to read all that the other answers suggest and whatever else you can find on the subject, because it's all good information to know and will make you a better programmer.
That said, one of the nice things about Django and other similar frameworks is that for the most part you don't have to know what's going on behind the scenes in the DB. Django adds indexes automatically for fields that need them. The encouragement to add more is based on the use cases of your app. If you continually query based on one particular field, you should ensure that that field is indexed. It might be already (if it's a foreign key, primary key, etc.), but other random fields typically aren't.
There's also various optimizations that are database client-specific. Django can't do much here because it's goal is to remain database independent. So, if you're using PostgreSQL, MySQL, whatever, read about optimizations and best practices concerning those particular clients.