Adds a unique index on questionbankentryid and version in the
question_versions table, to prevent various issues and query
performance.
Although there should not be, it's possible that there are existing
versions that violate this index, so the upgrade step finds these and
renumbers them.
This adds a new "nextversion" field to `question_bank_entries` to track
which version number the next version of the question should have. This
ensures that version numbers are not re-used if the latest version is
deleted.
To use this field, you must call
`\core_question\versions::get_next_version()`. This will initialise the
field to the correct value if it is currently null.
If you create a new version using this value, you must then call
`\core_question\versions::increment_next_version()` to increment the
counter.
Question banks were displaying in places they shouldn't, because
FEATURE_CAN_DISPLAY wasn't fully implemented. This broadens its
usage in the following areas:
- Availability info - Not relevant to qbank. However you could feasibly
have some module which isn't shown to students, but the teacher can
use
it to track completion, so dont display the link.
- Activities block - links to each activity's index page. We already
have
the Question banks page in the secondary nav. No need to have it here
too.
- Overview report - It doesn't make sense to display question banks
here,
as they're not an activity students can participate in, they wont have
dates etc.
- Externallib - Return with candisplay = false. The app needs to handle
this correctly.
- Visibility options, moodleform_mod, modvisible and visibility
selector.
Not relevant for qbank since it doesn't include the standard
coursemodule
options, but if an activity with without CAN_DISPLAY did display a
visibility setting, "Hidden" should be the only option.
- Activity names filter - we dont want automatic links to question
banks.
Identified performance bottlenecks in clear_cached_data() from
mod/quiz/report/statistics/report.php. The delete_records() calls on
question_statistics, question_response_analysis, and quiz_statistics tables
use the hashcode column for filtering, which becomes inefficient with large
datasets.
Huong Nguyen