fragment_downloaded_cb({"url":"tutorial.html#blank-nodes","fragment":"Blank nodes\nBlank nodes (or anonymous nodes) are nodes without an specified URI, these\nare given a query-local name via the special _: prefix:\nNote that running this query multiple times will insert a different blank\nnode each time. Unlike e.g.:\nWhere any second insert would be redundantly attempting to add the same\ntriple to the store.\nTracker deviates from the SPARQL standard in the handling of blank nodes.\nBy default blank nodes are not really anonymous, they get a generated\nunique URN. The SPARQL standard makes blank nodes truly anonymous, you can\nonly use them to determine that there is something that matches the graph\npattern you defined. The practical difference could be seen with this\nquery:\nTracker will provide you with URNs that can be fed into other SPARQL queries\nas URIs, while a other SPARQL engines will not. In these, the returned\nelements will be temporary names that can only be used to determine the\nexistence of a distinct match. There, blank nodes can match named nodes, but\nnamed nodes do not match with blank nodes.\nThis nature of blank nodes is however useful to query for elements whose\nresource URI is irrelevant, e.g.:\nIn this query there is no interest in getting the intermediate album\nand artist resources, so blank nodes can be used for them.\nBlank nodes have an in-place [ ] syntax, which declares a distinct\nempty blank node, it can also contain predicate/object pairs to further\ndefine the structure of the blank node. E.g. the previous query could\nbe rewritten like:\n"});