Intro to Relational Databases
This course is a quick, fun introduction to using a relational database from your code, using examples in Python. You'll learn the basics of SQL (the Structured Query Language) and database design, as well as the Python API for connecting Python code to a database. You'll also learn a bit about protecting your database-backed web apps from common security problems.
After taking this course, you'll be able to write code using a database as a backend to store application data reliably and safely.
If you look under the hood of a lot of major web sites — from Wikipedia to Reddit — you'll find a relational database somewhere.
Database systems such as PostgreSQL and MySQL have been part of the web developer's toolkit for many years, and remain some of the most powerful tools available for storing and manipulating structured data.
If you're planning to continue on in full-stack development, knowing about databases is essential background. Even though many toolkits hide the details of the database from your application code, being able to interact with the database will serve you well in designing, debugging, and maintaining your applications.
Lesson 1: Data and Tables
In this lesson, you'll learn about how relational databases let you structure data into tables. You'll learn about the importance of unique keys and relationships between tables.
Elephants Elements of SQL
In this lesson, you'll begin learning SQL, the Structured Query Language used by most relational databases. You'll learn about the select and insert statements, the basic operations for getting data out of a database and putting data into a database. You'll learn about the operators and syntax available to get the database to scan and join tables for you.
Lesson 3: Python DB-API
In this lesson, you'll learn how to access a relational database from Python code. You'll use a virtual machine (VM) running on your own computer to run a Python web application, and adapt that application to use a database backend. Then you'll learn about some of the most common security pitfalls of database-backed applications, including the famous Bobby Tables. This lesson also covers the SQL update and delete statements.
Lesson 4: Deeper Into SQL
In this lesson, you'll learn how to design and create new databases. You'll learn about normalized design, which makes it easier to write effective code using a database. You'll also learn how to use the SQL join operators to rapidly connect data from different tables.
Lesson 5: Final Project
In this project, you'll use your Python and SQL knowledge to build a database-backed Python module to run a game tournament. You'll design the database schema and write code to implement an API for the project.
You can read and write basic code in Python. This course uses programming exercises in Python. If you haven't worked with Python before, check out our course Programming Foundations with Python.
If you can understand this code (maybe with the help of the random module documentation), you know enough Python for this course:
import random def ChooseTwice(items): a = random.choice(items) b = random.choice(items) return a, b names = ["Alice", "Bob", "Charlie", "Debra"] (one, two) = ChooseTwice(names) if one == two: print "%s is happy!" % one else: print "%s likes %s!" % (one, two)
You can use a command-line interface (terminal). Some of the exercises in this course involve using a Unix-style command-line interface to enter commands, run Python programs, and navigate directories.
If you have taken our course on Git and Github, the level of command-line use in this course is similar.
You don't need any previous database experience. This course is an entry-level introduction to relational databases.
You need a programming text editor (such as Sublime Text) installed on your computer. You should be able to use it to open and edit files of Python code.