Hi,

Today is the day of questions to the mailing list ;) Sorry for the "spam" ;)

I would like to know what is the internal implementation of the
functions used for merging graphs.

1) ModelFactory.createUnion(Model m1, Model m2)
It seems from what I have read and inferred from some websites that
there is not an actual copy of data on a new graph. It is more that
internally the graph pointers (like in C) are linked, but the data is
the original one and not copied. Is that right?

2) org.apache.jena.graph.compose.MultiUnion
How is the addGraph() works? Is it copying the original graph or it is
just linking the data? I'm confused by the help : " Note that the
requirement to remove duplicates from the union means that this will be
an expensive operation for large (and especially for persistent) graphs. "
Besides, how do I retrieved the merged/joint graph? Do I have to use
option 1) in an iterative way, reusing the returned graph to add the
additional one?

Thanks in advance for the help.
Jorge

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