Groups
Improved groups/groupings design in Moodle 1.9
The groups related database structure in 1.9 was reverted to 1.7, groupings are now implemented in a different way than in 1.8. The current design is compatible with 1.7 style groups.
Other proposals
Changed groups/groupings relationship
In 1.8 both groups and groupings are not linked strictly to one course, you could use one group in several courses and groupings at the same time. This loose relationship of groups and groupings adds too much complexity and could be/is a source of bugs in code.
Solution: Each group and grouping links the course id directly. Groupings are only limiting the number of usable groups in activities. This allows free sharing of groups in groupings inside course without potential problems. This idea was proposed by Enrique. See attached db schema.
course
- groupingid - default grouping used in course (new activities, etc.)
course_modules
- groupingid - grouping used in activity
- groupmembersonly - limit access to and visibility of activity based on group membership - if user is not member of at least one group in grouping, the activity is invisible for them; this needs a new shared option in course/moodleform_mod.php
groupings_groups
renamed table
groups
reverted to pre 1.8 state (with the password exception)
Benefits
- fewer tables
- normalized
- simpler SQL
- easier backup/restore implementation
- fully compatible with old group implementation in 1.7
Linked groups
Maybe in future - it would allow synchronizing of group membership from different courses; the idea is to have linkid in groups table and synchronize the groups membership in group functions for adding/removing of members for groups with the same linkid.
Group/grouping cloning
Cloning or duplicating is UI feature only, it helps to prefill new groups/groupings with existing data. In theory it could also copy existing grouping setups from other courses too.
Other code cleanup
Current group code does not follow Moodle coding guide, has several unfinished/broken/obsoleted parts, is not integrated into core, etc. To do:
- integrate setup and upgrade into main lib/db/*.*
- remove columns from groupings table that can be replaced by permissions
- reduce the number of functions, rewrite or fix them, move them into lib/grouplib.php
- rewrite UI in /group/
- implement module and course groupings support, fix all mods to use it (course edit form, mod edit form, etc.)
- fix legacy functions
- documentation
Needed time
1 month for implementation and testing.
