I am new to semantic-web and ontology. From few weeks ago I am start reading papers and online course about it. I have an idea to use ontology rule-based system for extending the feature on my existing reminder system, as can be seen in the attached picture. I've read about Ontology, Rules (e.g. SPIN, SPARQL), Inference engine (e.g. Jena), RDF, RDFS, OWL etc. I think I've got the general idea about it.
System Architecture:

However, one thing that I still miss is: how to integrate this rule-based system into my current system. the current system data is stored in RDBMS (mysql) database. Every transaction data on the system has the possibility to be modified in later time after creation. Meanwhile, ontology-based system - AFAIK, rely on RDF data format. My thinking is, there should be a way to convert the trx data from RDBMS to RDF to be ready to use by the ontology system.
My question are:
- Does my thinking correct?
- What is best practise of this process?
- When there is a modified data on the existing record (RDBMS), how to reflect it on the RDF?
- In relation to #3, in case of not using RDBMS, how the ontology system manage their RDF data if there is an update of individual property? is that depend on the underlying triple-store database? Since I read that using TDB only able to insert or delete.