[Wikidata] Reg: How to fetch the sub properties and properties

Hi,

Is there a way to get the child properties/sub-properties of a property?

Example: position_held(P39) property has sub-properties like start time and end time so how to get them directly with SPARQL query and also If I have a wiki dump which is around 65 GB so how to parse a huge wiki dump and get the properties and their related sub-properties?

I got all the property IDs and property labels by SPARQL query but its inner properties like start time, end time.. so on were missed.

Thanks in advance!!

Thanks and Regards, VijayaLakshmi.