Okay, I have been learning SPARQL to query dbpedia and I can't seem to find clear and practical tutorials related to SPARQL and the Semantic Web. If I say that an ontology is analogous to an SQL table definition or maybe a specification of an object's members should I be slapped?
Most basically, the term "ontology" is roughly equivalent to the "domain model". It is the set of all objects that represent real world objects or concepts, including all defined relationships, rules, attributes and other metadata that is known or must be assumed as true about these objects within the bounds of this domain.
In the Semantic Web, the "ontology" being discussed is the definition of the information available from a Semantic Web data store. It's contained in documents that conform to a standard called RDF (Resource Description Framework), which can be implemented or serialized as an XML document. Think of these definitions as having a similar purpose for Web 3.0 as WSDL or JSDL documents have for web services; they contain the metadata needed for a computer to generate the DTOs and make the calls to obtain the data.