Lesson 25. Using Triggers
In this lesson, you’ll learn what triggers are, why they are used, and how. You’ll also look at the syntax for creating and using them.
Understanding Triggers
T-SQL statements are executed when needed, as are stored procedures. But what if you want a statement (or statements) to be executed automatically when events occur? Here are some examples:
• Every time a customer is added to a database table, check that the phone number is formatted correctly and that the state abbreviation is in uppercase.
• Every time a product is ordered, subtract the ordered quantity from the number in stock.
• Whenever a row is deleted, save a copy in an archive table.
What all these examples have in common ...
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