MySQL Triggers are changing in 5.7 in a big way. Triggers have been around since 5.0 and have not changed much up to 5.6 but will gain the ability to have multiple triggers on the same event. Previously you had ONE trigger maximum on a BEFORE UPDATE, for example, and now you can have multiple triggers and set their order.
So what is a trigger? Triggers run either BEFORE or AFTER an UPDATE, DELETE, or INSERT is performed. You also get access to the OLD.col_name and NEW.col_name variables for the previous value and the newer value of the column.
So how do you use a trigger? Let say you are updating the price of an inventory item in a product database with a simple UPDATE statement. But you also want to track when the price change and the old price.
The table for products.