60 lines
1.9 KiB
PL/PgSQL
60 lines
1.9 KiB
PL/PgSQL
-- Migration: Automatic Enrollment Progress Update via Trigger
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-- Created: 2026-04-14
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-- 1. Function to recalculate course progress for a student
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CREATE OR REPLACE FUNCTION fn_recalculate_enrollment_progress()
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RETURNS TRIGGER AS $$
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DECLARE
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v_total_lessons INTEGER;
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v_completed_lessons INTEGER;
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v_progress FLOAT4;
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BEGIN
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-- Get total number of lessons in the course
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-- We use the course_id from the new grade entry
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SELECT COUNT(*) INTO v_total_lessons
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FROM lessons
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WHERE module_id IN (SELECT id FROM modules WHERE course_id = NEW.course_id);
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-- Get number of distinct lessons with a grade for this user in this course
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SELECT COUNT(DISTINCT lesson_id) INTO v_completed_lessons
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FROM user_grades
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WHERE user_id = NEW.user_id AND course_id = NEW.course_id;
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-- Calculate progress percentage
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IF v_total_lessons > 0 THEN
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v_progress := (v_completed_lessons::FLOAT4 / v_total_lessons::FLOAT4) * 100;
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ELSE
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v_progress := 0;
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END IF;
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-- Update the enrollments table for this specific user and course
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UPDATE enrollments
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SET progress = v_progress
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WHERE user_id = NEW.user_id AND course_id = NEW.course_id;
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RETURN NEW;
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END;
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$$ LANGUAGE plpgsql;
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-- 2. Trigger to execute the function after any activity is graded
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DROP TRIGGER IF EXISTS tr_update_enrollment_progress ON user_grades;
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CREATE TRIGGER tr_update_enrollment_progress
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AFTER INSERT OR UPDATE ON user_grades
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FOR EACH ROW
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EXECUTE FUNCTION fn_recalculate_enrollment_progress();
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-- 3. Initial sync: Update progress for all existing enrollments
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UPDATE enrollments e
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SET progress = COALESCE(
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(
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SELECT (COUNT(DISTINCT ug.lesson_id)::FLOAT4 / NULLIF((
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SELECT COUNT(*)
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FROM lessons l
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WHERE l.module_id IN (SELECT id FROM modules m WHERE m.course_id = e.course_id)
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), 0)::FLOAT4) * 100
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FROM user_grades ug
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WHERE ug.user_id = e.user_id AND ug.course_id = e.course_id
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),
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0
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);
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