In my company we have a 10 years old MES app that's based on the idea of aggregating daily and hourly readings from PI into an Oracle DB while building an ISA-95 model using tables like equipments, UOM, materials, etc. The main apps here are Emissions Monitoring, Production Accounting, Validation for Online Analyzers and Operations Logs. We're seriously thinking to revamp this model and use an AF based solution. However, I have some worries that I need your help to clarify. One of the main tables we have in Oracle is the'Readings' table which contains millions of record but have a useful feature which is to allow certain user to validate certain readings based on their knowledge of operations, the question is how to implement this in PI/AF, where to store the validated figures and have an audit trail for that. Also, I'd appreciate it if you can share any materials of references for developing such kind of the mentioned apps on top of AF and whether we can proceed without a RDBMS or not.