AFTER INSERT triggers in MySQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is an AFTER INSERT trigger in MySQL?

An AFTER INSERT trigger is a special set of instructions that run automatically right after a new row is added to a table. It lets you perform extra actions based on the new data.

beginner

When exactly does an AFTER INSERT trigger execute?

It executes immediately after the new row is successfully inserted into the table, allowing you to react to the insertion.

intermediate

Can an AFTER INSERT trigger modify the row that was just inserted?

No, AFTER INSERT triggers cannot change the inserted row because the insertion is already done. To modify data before insert, use BEFORE INSERT triggers.

beginner

How do you access the new row's data inside an AFTER INSERT trigger?

You use the keyword NEW followed by the column name, like NEW.column_name, to get the values of the inserted row.

beginner

Give a simple example use case for an AFTER INSERT trigger.

You can use it to log every new user added to a users table into a separate audit table, keeping track of who was added and when.

When does an AFTER INSERT trigger run in MySQL?

A When a row is deleted

B Right after a new row is inserted

C When a row is updated

D Before a new row is inserted

AFTER INSERT triggers run immediately after a new row is successfully inserted into the table.

Which keyword lets you access the new row's data inside an AFTER INSERT trigger?

A NEW

B OLD

C CURRENT

D ROW

The NEW keyword is used to access the inserted row's column values inside the trigger.

Can an AFTER INSERT trigger modify the inserted row's data?

A Only if the trigger is BEFORE INSERT

B Yes, always

C Only if the table has no primary key

D No, it cannot

AFTER INSERT triggers cannot modify the inserted row because the insertion is already complete.

Which of these is a common use of AFTER INSERT triggers?

A Log inserted data to another table

B Prevent insertion of duplicate rows

C Validate data before insert

D Update the inserted row's values

AFTER INSERT triggers are often used to log or audit inserted data after it is saved.

What happens if an AFTER INSERT trigger fails during execution?

A The insert still succeeds but trigger actions are skipped

B The database shuts down

C The insert is rolled back

D The trigger runs again automatically

If an AFTER INSERT trigger fails, the entire insert operation is rolled back to keep data consistent.

Explain what an AFTER INSERT trigger is and when it runs in MySQL.

Think about what happens right after you add a new row to a table.

Describe a practical example where you might use an AFTER INSERT trigger.

Consider how you might keep track of changes automatically.