A trigger is a special type of stored procedure in a database that automatically executes when an event occurs in the database.
Example of trigger :
A real-world application example of triggers is an order management system. For example, when an order is placed, a trigger can be used to automatically check if there is enough stock to fulfill the order. If there is sufficient stock, the trigger can update the inventory in the database and send a notification to the customer that the order has been successfully processed. If there is insufficient stock, the trigger can update the customer with the new delivery date. This helps to ensure that orders are fulfilled quickly and efficiently, while maintaining data integrity.
Data describes figures and facts. It may consist of one entry or a collection of different values. Information describes values and context together, resulting in something meaningful.
"true" is a string type of data. String types of data are lines of text between quotation marks. They are generally used for displaying text to users but can be helpful for debugging as well.
Use composition when you can, private inheritance when you have to. Normally you don't want to have access to the internals of too many other classes, and private inheritance gives you some of this extra power