Book Image

The MySQL Workshop

By : Thomas Pettit, Scott Cosentino
5 (1)
Book Image

The MySQL Workshop

5 (1)
By: Thomas Pettit, Scott Cosentino

Overview of this book

Do you want to learn how to create and maintain databases effectively? Are you looking for simple answers to basic MySQL questions as well as straightforward examples that you can use at work? If so, this workshop is the right choice for you. Designed to build your confidence through hands-on practice, this book uses a simple approach that focuses on the practical, so you can get straight down to business without having to wade through pages and pages of dull, dry theory. As you work through bite-sized exercises and activities, you'll learn how to use different MySQL tools to create a database and manage the data within it. You'll see how to transfer data between a MySQL database and other sources, and use real-world datasets to gain valuable experience of manipulating and gaining insights from data. As you progress, you'll discover how to protect your database by managing user permissions and performing logical backups and restores. If you've already tried to teach yourself SQL, but haven't been able to make the leap from understanding simple queries to working on live projects with a real database management system, The MySQL Workshop will get you on the right track. By the end of this MySQL book, you'll have the knowledge, skills, and confidence to advance your career and tackle your own ambitious projects with MySQL.
Table of Contents (22 chapters)
1
Section 1: Creating Your Database
6
Section 2: Managing Your Database
11
Section 3: Querying Your Database
16
Section 4: Protecting Your Database

Flush privileges

Many tutorials and instructions to set up applications tell the users to issue FLUSH PRIVILEGES. So, what is this? And when do we need to use it?

The CREATE USER, ALTER USER, and GRANT permissions, along with many other user and permission statements, indirectly modify the system tables that are stored in the mysql schema. At startup, these tables are loaded into memory and, after every statement that modifies the users and/or permissions, these are again loaded into memory.

However, if you directly modify the tables in the mysql schema with INSERT, UPDATE, and DELETE statements, you need to force MySQL to refresh the copies of these tables it has in memory. This is where the FLUSH PRIVILEGES statement comes in. It precisely does that. Note that we do not recommend you modify these tables directly. So, as long as you stick to the supported commands to modify users, you never need to use this command.