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Intro to Relational Databases

Free Course

SQL, DB-API, and More!

Related Nanodegree Program

Introduction to Programming

About this course

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.

What you will learn

  1. Data and Tables
    • Learn about how relational databases let you structure data into tables.
    • Learn about the importance of unique keys and relationships between tables.
  2. Elements of SQL
    • Begin learning SQL, the Structured Query Language used by most relational databases.
    • Learn about the select and insert statements, the basic operations for reading and writing data.
    • Learn about the operators and syntax available to get the database to scan and join tables for you.
  3. Python DB-API
    • Learn how to access a relational database from Python code.
    • Use a virtual machine (VM) to run a Python web application with a database.
    • Common security pitfalls of database applications, including the famous Bobby Tables.
  4. Deeper Into SQL
    • Learn how to design and create new databases.
    • Learn about normalized design, which makes it easier to write effective code using a database.
    • Learn how to use the SQL join operators to rapidly connect data from different tables.

Prerequisites and requirements

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
    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 to be a Web programmer. This course does include a small Web application and some HTML and JavaScript in examples, but you will not need to make changes in these languages.

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.

See the Technology Requirements for using Udacity.

Why take this course?

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.

Learn with the best.

  • Karl Krueger
    Karl Krueger