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)

Functions

The complexity of the software we build expands as we build it. In part, this becomes unavoidable because the mass of the software itself also expands. However, we can definitely avoid the complexity of repeating blocks of code. Modern software development products give us a way to place one copy of a repeating block of code in one defined location. Then, in the software, we can replace all repeated instances of that code block with a call to that one defined copy of the code. We call this one defined block of software a function. Think of a function as a box that takes in zero or more values and returns one or more values in a structured way. A function simplifies software, and it makes the software we build much easier to maintain, repair, and enhance. If a program has the same identical code block repeated one hundred times, the same required change to all of those blocks would require the same work and testing—one hundred times. If we replace those blocks with...