Book Image

The Data Wrangling Workshop - Second Edition

By : Brian Lipp, Shubhadeep Roychowdhury, Dr. Tirthajyoti Sarkar
Book Image

The Data Wrangling Workshop - Second Edition

By: Brian Lipp, Shubhadeep Roychowdhury, Dr. Tirthajyoti Sarkar

Overview of this book

While a huge amount of data is readily available to us, it is not useful in its raw form. For data to be meaningful, it must be curated and refined. If you’re a beginner, then The Data Wrangling Workshop will help to break down the process for you. You’ll start with the basics and build your knowledge, progressing from the core aspects behind data wrangling, to using the most popular tools and techniques. This book starts by showing you how to work with data structures using Python. Through examples and activities, you’ll understand why you should stay away from traditional methods of data cleaning used in other languages and take advantage of the specialized pre-built routines in Python. Later, you’ll learn how to use the same Python backend to extract and transform data from an array of sources, including the internet, large database vaults, and Excel financial tables. To help you prepare for more challenging scenarios, the book teaches you how to handle missing or incorrect data, and reformat it based on the requirements from your downstream analytics tool. By the end of this book, you will have developed a solid understanding of how to perform data wrangling with Python, and learned several techniques and best practices to extract, clean, transform, and format your data efficiently, from a diverse array of sources.
Table of Contents (11 chapters)

Refresher of RDBMS and SQL

An RDBMS is a piece of software that manages data (represented for the end user in tabular form) on physical hard disks and is built using Codd's relational model. Most of the databases that we encounter today are RDBMS. In recent years, there has been a huge industry shift toward a newer kind of database management system, called NoSQL (MongoDB, CouchDB, Riak, and so on). These systems, while they do follow some of the rules of RDBMS in certain aspects, in most cases they reject or modify them.

How Is an RDBMS Structured?

The RDBMS structure consists of three main elements, namely the storage engine, the query engine, and log management. Here is a diagram that demonstrates the structure of an RDBMS:

Figure 8.2: RDBMS structure

The following are the main concepts of any RDBMS structure:

  • Storage engine: This is the part of the RDBMS that is responsible for storing data in an efficient way and also retrieving it,...