Is there any advantage of using ontology based database (linked data) instead of RDBMS in an offline application? Does linked data provide more relations and reasoning capabilities using SPARQL than SQL? Can I not achieve the same using joins in SQL?
Suppose I am storing the details of various mobile phones. This database should answer user centric queries like 1.list of all mobiles with good (quantified) touch interface 2.mobiles similar to Samsung Galaxy s4
Can I not retrieve efficient results using RDBMS itself with joins? If the answer is yes, then would the performance of answering these queries between the two database models be of argument here? Basically what is the edge that I get get by using ontologies in such scenarios?
The main advantage of using ontologies is the formalized semantics. This way a reasoner can automatically infer new statements without writing specific code.
But it's true, that you can model every Linked Data also in RDBMS and the other way around. The same is true for querying with SPARQL or SQL. You can achieve the same results. SPARQL has some advantages if your SQL query requires multiple joins. This can be expressed in a far more meaningful way in SPARQL.
The disadvantage of ontology based databases is nowadays still a lack of performance in comparison to RDBMS.