Interactive Course

Introduction to Databases in Python

In this course, you'll learn the basics of relational databases and how to interact with them.

4 hours
20 Videos
66 Exercises
43,526 Participants
5,550 XP

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Course Description

In this Python SQL course, you'll learn the basics of using Structured Query Language (SQL) with Python. This will be useful since whether you like it or not, databases are ubiquitous and, as a data scientist, you'll need to interact with them constantly. The Python SQL toolkit SQLAlchemy provides an accessible and intuitive way to query, build & write to SQLite, MySQL and Postgresql databases (among many others), all of which you will encounter in the daily life of a data scientist.

In this chapter, you will become acquainted with the fundamentals of Relational Databases and the Relational Model. You will learn how to connect to a database and then interact with it by writing basic SQL queries, both in raw SQL as well as with SQLAlchemy, which provides a Pythonic way of interacting with databases.

Herein, you will learn to perform advanced - and incredibly useful - queries that will enable you to interact with your data in powerful ways.

Here, you will bring together all of the skills you acquired in the previous chapters to work on a real life project! From connecting to a database, to populating it, to reading and querying it, you will have a chance to apply all the key concepts you learned in this course. Enjoy!

In this chapter, you will build on the database knowledge you began acquiring in the previous chapter by writing more nuanced queries that allow you to filter, order, and count your data, all within the Pythonic framework provided by SQLAlchemy!

In the previous chapters, you interacted with existing databases and queried them in various different ways. Now, you will learn how to build your own databases and keep them updated!

1
Basics of Relational Databases
Free

In this chapter, you will become acquainted with the fundamentals of Relational Databases and the Relational Model. You will learn how to connect to a database and then interact with it by writing basic SQL queries, both in raw SQL as well as with SQLAlchemy, which provides a Pythonic way of interacting with databases.
View Chapter Details Play Chapter Now
Applying Filtering, Ordering and Grouping to Queries

In this chapter, you will build on the database knowledge you began acquiring in the previous chapter by writing more nuanced queries that allow you to filter, order, and count your data, all within the Pythonic framework provided by SQLAlchemy!
View Chapter Details Play Chapter Now
Advanced SQLAlchemy Queries

Herein, you will learn to perform advanced - and incredibly useful - queries that will enable you to interact with your data in powerful ways.
View Chapter Details Play Chapter Now
Creating and Manipulating your own Databases

In the previous chapters, you interacted with existing databases and queried them in various different ways. Now, you will learn how to build your own databases and keep them updated!
View Chapter Details Play Chapter Now
Putting it all together

Here, you will bring together all of the skills you acquired in the previous chapters to work on a real life project! From connecting to a database, to populating it, to reading and querying it, you will have a chance to apply all the key concepts you learned in this course. Enjoy!
View Chapter Details Play Chapter Now

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Jason Myers

Co-Author of Essential SQLAlchemy and Software Engineer

Jason Myers is a software engineer and author. His area of expertise is in developing data analytics platforms. He has also written the Essential SQLAlchemy book, co-authored with Rick Copeland, that introduces you to working with relational databases in Python.

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Introduction to Databases in Python

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Course Description

Basics of Relational Databases

Introduction to Databases

Relational Model

Connecting to your Database

Engines and Connection Strings

Autoloading Tables from a Database

Viewing Table Details

Introduction to SQL

Selecting data from a Table: raw SQL

Selecting data from a Table with SQLAlchemy

Handling a ResultSet

Congratulations!

Advanced SQLAlchemy Queries

Calculating Values in a Query

Connecting to a MySQL Database

Calculating a Difference between Two Columns

Determining the Overall Percentage of Females

SQL Relationships

Automatic Joins with an Established Relationship

Joins

More Practice with Joins

Working with Hierarchical Tables

Using alias to handle same table joined queries

Leveraging Functions and Group_bys with Hierarchical Data

Dealing with Large ResultSets

Working on Blocks of Records

Putting it all together

Census Case Study

Setup the Engine and MetaData

Create the Table to the Database

Populating the Database

Reading the Data from the CSV

Load Data from a list into the Table

Example Queries

Build a Query to Determine the Average Age by Population

Build a Query to Determine the Percentage of Population by Gender and State

Build a Query to Determine the Difference by State from the 2000 and 2008 Censuses

Congratulations

Applying Filtering, Ordering and Grouping to Queries

Filtering and Targeting Data

Connecting to a PostgreSQL Database

Filter data selected from a Table - Simple

Filter data selected from a Table - Expressions

Filter data selected from a Table - Advanced

Overview of Ordering

Ordering by a Single Column

Ordering in Descending Order by a Single Column

Ordering by Multiple Columns

Counting, Summing and Grouping Data

Counting Distinct Data

Count of Records by State

Determining the Population Sum by State

Let's use Pandas and Matplotlib to visualize our Data

SQLAlchemy ResultsProxy and Pandas Dataframes

From SQLAlchemy results to a Graph

Creating and Manipulating your own Databases

Creating Databases and Tables

Creating Tables with SQLAlchemy

Constraints and Data Defaults

Inserting Data into a Table

Inserting a single row with an insert() statement

Inserting Multiple Records at Once

Loading a CSV into a Table

Updating Data in a Database

Updating individual records

Updating Multiple Records

Correlated Updates

Removing Data From a Database

Deleting all the records from a table

Deleting specific records

Deleting a Table Completely