Report conditions allow report creators to limit which data
is displayed when the report is viewed. Users viewing the
report cannot override these condition values.
Entities are re-usable collections of report columns and filters. When
creating system reports, we can re-use those elements from entities
without having to know specific details about their implementation.
They can be joined to reports, or other entities, using standard SQL
query syntax.
Define base classes, and create two example entities: course and user.
Co-Authored-By: David Matamoros <davidmc@moodle.com>