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)

Second Normal Form (2NF)

Before you understand the second normal form, let's explore what dependency is with the help of the following scenario.

In an enterprise, it is important that the security updates are installed on every server. This process is known as patching the servers. Typically, updates get installed every month, and at the end of the month, many organizations check the percentage of servers that had been patched during the month. This number is calculated based on how many servers have how many patches in the installed and not required state. This calculation is done per server. Apart from the operating system updates, we would also like to install application updates. Therefore, based on what team we are talking about and what applications they own, the percentage of compliance can change.

For example, imagine that Microsoft released four updates to the Windows operating system. Citrix Systems, Inc, a multinational software company, released one update to...