Documentation
Add mandatory rules and preferences
Mandatory rules are requirements the timetable must satisfy. Preferences are desirable patterns that can bend when the school has limited options. Use mandatory rules for real blockers and preferences for quality improvements.
Last updated: May 12, 2026 ยท Reviewed by the Schedull product team
Decision table
Classify every rule before entering it. This prevents useful preferences from blocking timetable generation.
| Rule | Better as |
|---|---|
| Teacher cannot work Friday afternoon | Mandatory rule |
| Math is better in the morning | Preference |
| Lab lesson needs a lab | Mandatory rule |
| Avoid last period when possible | Preference |
Review before generation
Too many mandatory rules can leave no valid timetable. Start with real blockers, generate, and then add preferences for timetable quality.
- Enter true blockers first.
- Keep preferences flexible.
- Review failed runs by relaxing low-priority rules.
FAQ
Can I convert a mandatory rule into a preference?
Yes. If a rule describes a desirable pattern rather than a real requirement, treat it as a preference and regenerate.