BEFORE and AFTER Triggers

Trigger Timing

BEFORE Trigger

CREATE TRIGGER before_marks_insert
BEFORE INSERT ON students
FOR EACH ROW
SET NEW.marks = LEAST(NEW.marks, 100);  -- cap marks at 100

AFTER Trigger

AFTER triggers run once the row is committed — used for logging, updating totals in another table, etc.

Summary

• BEFORE = validate/modify data before saving.
• AFTER = react after the change (logging, summaries).

Trigger Timing

BEFORE Trigger

CREATE TRIGGER before_marks_insert
BEFORE INSERT ON students
FOR EACH ROW
SET NEW.marks = LEAST(NEW.marks, 100);  -- marks 100 पर cap

AFTER Trigger

AFTER triggers row commit होने के बाद चलते हैं — logging, दूसरी table में totals update करने आदि के लिए।

सारांश

• BEFORE = save से पहले data validate/modify।
• AFTER = change के बाद react (logging, summaries)।