Transactions

As part of database management, soon enough, we will probably make direct data changes through database management tools. In other words, we may use a MySQL query window to make a direct insert, update, and delete changes to live production data. We know how to make those changes with relevant SQL statements, but so far, we have not looked at a way to reverse these changes. Even one mistake could potentially destroy data resources worth billions. Fortunately, SQL products offer the TRANSACTION function as a way to execute SQL statements in a reversible way.

From the PACKT_ONLINE_SHOP database, from the Products table, let's query the product with the product ID 3:

USE PACKT_ONLINE_SHOP;
SELECT    ProductID, Availablequantity
FROM      Products
WHERE     productid = 3;

This query will yield the following output:

Figure 11.16: The output of the query before update

From the output, we can see that the product with product ID 3 has 1...