Explain what a trigger is in SQL and how it is used to automate operations in a database.

A trigger in SQL is a special database object that automatically executes a specified set of actions (such as SQL queries) when certain events (INSERT, UPDATE, DELETE) occur on a table.

Triggers are used to automate tasks such as:

• Data integrity checks and maintenance
• Logging changes
• Automatic updating of related tables

An example of a trigger that automatically updates the order count in the customers table when a record is inserted into the orders table:

CREATE TRIGGER UpdateOrderCount
AFTER INSERT ON orders
FOR EACH ROW
BEGIN
  UPDATE customers SET order_count = order_count + 1 WHERE id = NEW.customer_id;
END;

Thus, triggers help automate business logic at the database level.