Background
Most OpenMRS tables include auditing attributes:
changed_bydate_changedvoided_bydate_voidedvoid_reason
These have limitations and require that tables contain audit history. We also end up supporting similar audit capabilities in several places within the API. We would like to centralize these auditing functions within a central audit service.
The "creator" and "date_created" columns can be left on the original tables. Moving them to a centralized table can be discussed at a later point.
The audit information is currently placed on objects as they are saved automatically by the RequiredDataAdvice/SaveHandlers and/or the AuditableInterceptor hibernate class.
Design
A single 'audit' table will hold the values above along with a "blob" type of column and a "type" column. The blob is serialized xml. The type is the class that is being modified.
We should start with one object to try this on before implementing system wide. It has been suggested that something like person_address would be suitable.
Design Goals
- Remove the redundant columns in almost every table for creator/dateCreated etc.
- Keep a record of what actually changed from one version to the next (e.g., an xml blob).
- Keep all the history for an object instead of just the most recent change.
- Avoid tight binding to specific domain objects; more specifically, have a strategy for easily handling additional types in the future.
Road-map
1. Create a table (audit_log), corresponding class (AuditLog) and hibernate mapping.
2. Replace AuditableInterceptor to handle updates and deletes. On an update/delete, the AuditableInterceptor will make an appropriate entry in audit_log.
3. The audit_log table has a blob field which stores a XML file which contains the previous and current state of the modified object.
4. Create an AuditService, which will allow the administrator to view entries in the audit_log.
Assigned Developer
Ankur Gupta, Niranjan Kulkarni, Rohit Manohar,