Virtual graph mapping format

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1

I'm a little confused about the virtual graph mapping format. I checked the help page

stardog-admin help virtual add

and it lists the format options as STARDOG, SMS and R2RML. I was a little confused with the STARDOG option but figured it must be for SMS2 since it's not in the list and it does stand for Stardog Mapping Syntax 2 although the documentation refers to it as SMS2. I went to add a virtual graph with the mappings in SMS2 syntax with the -f STARDOG flag and it threw an error. It appeared as though it was trying to parse it as turtle. I had previously used an extension of .sms2 but it complained that it wasn't a valid RDF serialization. SMS2 isn't turtle but I figured it was close enough so I changed the extension to ttl.

I then tried importing it with -f SMS2 and it worked. No errors or warnings in the logs and the virtual add command completed successfully although I'm not getting any results from the virtual graph but that could be because I have something wrong in the mapping.

2

It should say SMS2, not SMS. Do you see something different? Command Line Interface | Stardog Documentation Latest

3

My bad. It's SMS2. So STARDOG is SMS? I can't remember but I guess it used to be STARDOG and R2RML and then SMS2 came along. I thought SMS wasn't technically turtle. No matter. Seems to be a problem with my brain.

4

Right, STARDOG is the format name for what we generally refer to as SMS. We called it "Stardog Mapping Syntax" initially and used STARDOG as the format name. As things evolved, we decided to call the new one SMS2.

And regarding SMS as Turtle, it's not valid turtle but the parsing happens in two stages, the second of which is valid Turtle.

5

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