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)

The Concept of Normalization

Suppose we have a piece of software in our enterprise called Enterprise Server Manager that manages all the computers. The Enterprise Server Manager (ESM) has information about what computers we have, the operating system they run on, the version of the operating system, and so on.

Now, each server works for one or more teams. The respective teams have all the authority on these servers, along with being responsible for them. Imagine that you want the heads of the teams tagged as the owners of the servers. The server entries should contain the employee IDs, the names, the designations, and the department names of these owners. Here is an example:

Figure 3.1: ESM Agent details

The preceding table has all the information we need and the data looks consistent for now, right? Jon Doe's information is being repeated, though. Is that an issue?

Imagine that Jon Doe leaves the organization and Jim Doe replaces him. Now, imagine...