Book Image

MariaDb Essentials

By : Kenler
Book Image

MariaDb Essentials

By: Kenler

Overview of this book

This book will take you through all the nitty-gritty parts of MariaDB, right from the creation of your database all the way to using MariaDB’s advanced features. At the very beginning, we show you the basics, that is, how to install MariaDB. Then, we walk you through the databases and tables of MariaDB, and introduce SQL in MariaDB. You will learn about all the features that have been added in MariaDB but are absent in MySQL. Moving on, you’ll learn to import and export data, views, virtual columns, and dynamic columns in MariaDB. Then, you’ll get to grips with full-text searches and queries in MariaDb. You’ll also be familiarized with the CONNECT storage engine. At the end of the book, you’ll be introduced to the community of MariaDB.
Table of Contents (10 chapters)
9
Index

Understanding transactions


A transaction is a sequence of SQL statements that are grouped into a single logical operation. Its purpose is to guarantee the integrity of data. If a transaction fails, no change will be applied to the databases. If a transaction succeeds, all statements will succeed.

Why is this so important? Consider the following example:

START TRANSACTION;
SELECT quantity FROM product WHERE id = 42;
UPDATE product
  SET quantity = quantity - 10
  WHERE id = 42;
UPDATE customer
  SET money = money -
  (SELECT price FROM product WHERE id = 42)
  WHERE id = 512;
INSERT INTO product_order
  (product_id, quantity, customer_id)
  VALUES (42, 10, 512);
COMMIT;

We haven't yet discussed some of the statements used in the preceding example. However, they are not transactions we need to understand. This sequence of statements happens when a customer (whose id is 512) orders a product (with id 42). As a consequence, we need to execute the following sub-operations in our database:

  • Check...