I have a huge .xml file with millions of rows and I want to transform it to a YANG model. Is there a tool that can solve this problem?
YANG has an XML representation, so you're transforming one XML vocabulary to another and the typical tool for that is XSLT. How difficult it is depends on how much difference there is between the two vocabularies. "Millions of rows" sounds like it might be less than 100Mb in which case conventional XSLT processing is quite feasible; if it's more than that, then you might be able to use streamed XSLT processing (requires XSLT 3.0) but whether that's feasible depends on the complexity of the transformation.