Glossary & Domain Terms

Authoritative definitions for academic concepts, database constructs, and architectural subsystems in Attendrix.

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A

• Absence Record: An explicit entry in public.absences indicating that a student did not attend a specific class occurrence.
• Action Tone: The personality setting configured in user_preferences (direct, playful, roast, motivational) that governs the style of push notifications.
• Amplix: The student engagement and gamification points system. Points are tracked in public.amplix_ledger and awarded for maintaining attendance streaks and completing academic challenges.
• APOD (Astronomy Picture of the Day): Daily educational astronomy photograph and caption ingested from NASA into public.apod.

B

• Batch: An academic cohort within a department (e.g. CSE_2023) sharing core curricula, semester timetables, and lecture halls.
• Batch Course: A mandatory course mapped to a batch via public.batch_courses.
• Bunk Margin: The maximum number of upcoming classes a student can safely miss while keeping their projected attendance above the required threshold ($T$).

C

• Class (Class Slot): A concrete, dated occurrence of a lecture, lab, or tutorial in public.classes, with a scheduled start time, end time, and venue.
• Course: An academic subject in public.courses defined by an institutional code (e.g. CS301), credit weighting, syllabus, and course type.
• Course Meeting: The relational mapping binding a course to a recurring slot occurrence and physical room in public.course_meetings.

E

• Elective Course: A course selected by a student from a departmental or institute-wide offering basket, recorded in public.user_course_enrollments.
• Extra Class: An ad-hoc lecture scheduled outside standard recurring timetable slots (is_extra_class = true).

G

• Google Calendar Sync Worker: The Deno Edge Function (google-calendar-sync-worker) that consumes gcal_sync_queue and reconciles student timetables with Google Calendar.

I

• Inverted Attendance: The persistence paradigm where presence is default, and only absences are stored in the database.
• Invariant: A formal engineering guarantee that the system promises to uphold across all executions (e.g. INV-ATT-01, INV-SEC-01).

P

• PGMQ (PostgreSQL Message Queues): Lightweight, transactional message queuing extension inside PostgreSQL used for notification_queue and gcal_sync_queue.
• Plus Slot: A dedicated supplementary tutorial, quiz, or discussion session associated with a course slot (is_plus_slot = true).

Q

• Quiet Hours: A student-configured time window during which non-urgent push alerts are suppressed (user_preferences.quiet_hours_enabled).

R

• Recovery Deficit: The number of consecutive lectures a student must attend without missing to recover their attendance back up to the required threshold ($T$).
• Routing Matrix: The precomputed 152,904-pair pedestrian walking distance dataset cached on the mobile device for 100% offline navigation.

S

• Semester: An institutional academic term in public.semesters spanning 16–20 weeks.
• Slot Occurrence: A recurring periodic time block in the institutional master schedule (e.g. Monday 09:00–10:00).
• Soft Delete: Setting is_cancelled = true on a class rather than issuing an SQL DELETE, preserving historical attendance integrity.

V

• Vault (Supabase Vault): AES-256-GCM encrypted database store used to safeguard Google OAuth refresh tokens.