Book Image

The SQL Workshop

By : Frank Solomon, Prashanth Jayaram, Awni Al Saqqa
Book Image

The SQL Workshop

By: Frank Solomon, Prashanth Jayaram, Awni Al Saqqa

Overview of this book

Many software applications are backed by powerful relational database systems, meaning that the skills to be able to maintain a SQL database and reliably retrieve data are in high demand. With its simple syntax and effective data manipulation capabilities, SQL enables you to manage relational databases with ease. The SQL Workshop will help you progress from basic to advanced-level SQL queries in order to create and manage databases successfully. This Workshop begins with an introduction to basic CRUD commands and gives you an overview of the different data types in SQL. You'll use commands for narrowing down the search results within a database and learn about data retrieval from single and multiple tables in a single query. As you advance, you'll use aggregate functions to perform calculations on a set of values, and implement process automation using stored procedures, functions, and triggers. Finally, you'll secure your database against potential threats and use access control to keep your data safe. Throughout this Workshop, you'll use your skills on a realistic database for an online shop, preparing you for solving data problems in the real world. By the end of this book, you'll have built the knowledge, skills and confidence to creatively solve real-world data problems with SQL.
Table of Contents (13 chapters)

Third Normal Form (3NF)

Consider a situation where a conflict arises between you and your colleague during the calculation of the compliance percentage. Your colleague states, "Your way of calculating the compliance percentage is flawed! Look, one of Jon's servers gets four updates out of five and the other gets four out of six. You calculate individual servers, say 80% on one and 66.67% on the other. Then, you take an average and say the compliance percentage is 73.33%. Jon had to ensure the installation of 11 patches in all, out of which he installed only eight. His compliance percentage should actually be 72.73%, and not 73.33."

This situation has introduced a different level of complexity in our setup. Now, you need to look for a way to combine several aspects and introduce something that will allow for the calculation of the compliance percentage based on the total patches that are needed for a server per application combination, and the actual score for that...