Explain the principle of operation of triggers in databases and their purpose.

Triggers in databases are special procedures that automatically execute (fire) when certain events occur, such as inserting (INSERT), updating (UPDATE), or deleting (DELETE) data in a table.

The main purposes of triggers:

• Automating data integrity control.
• Logging changes in tables.
• Implementing business logic at the database level.
• Synchronizing data between tables.

Example: when a new record is added to the orders table, the stock quantity can be automatically updated.

In C#, triggers are usually implemented through SQL Server, and interaction with them occurs via ADO.NET or Entity Framework, where a trigger is part of the database, not directly C# code.