Apache Solr Reference Guide Covering Apache Solr 6.0

We can also use the traversalFilter to limit the graph traversal to only nodes with maximum value of 15 in
the foo field. In this case that means D, E, and F are excluded – F has a value of foo=11, but it is unreachable
because the traversal skipped D:
http://localhost:8983/solr/my_graph/query?fl=id&q={!graph+from=in_edge+to=out_edge+t
raversalFilter='foo:[*+TO+15]'}id:A
...
"response":{"numFound":3,"start":0,"docs":[
{ "id":"A" },
{ "id":"B" },
{ "id":"C" } ]
}
The examples shown so far have all used a query for a single document ("id:A") as the root node for the graph
traversal, but any query can be used to identify multiple documents to use as root nodes. The next example
demonstrates using the maxDepth param to find all nodes that are at most one edge away from an root node
with a value in the foo field less then or equal to 10:
http://localhost:8983/solr/my_graph/query?fl=id&q={!graph+from=in_edge+to=out_edge+m
axDepth=1}foo:[*+TO+10]
...
"response":{"numFound":6,"start":0,"docs":[
{ "id":"A" },
{ "id":"B" },
{ "id":"C" },
{ "id":"D" },
{ "id":"G" },
{ "id":"H" } ]
}
Simplified Models
The Document & Field modelling used in the above examples enumerated all of the outgoing and income edges
for each node explicitly, to help demonstrate exactly how the "from" and "to" params work, and to give you an
idea of what is possible. With multiple sets of fields like these for identifying incoming and outgoing edges, it's
possible to model many independent Directed Graphs that contain some or all of the documents in your
collection.
But in many cases it can also be possible to drastically simplify the model used.
For Example: The same graph shown in the diagram above can be modelled by Solr Documents that represent
each node and know only the ids of the nodes they link to, with out knowing anything about the incoming links:
curl -H 'Content-Type: application/json'
'http://localhost:8983/solr/alt_graph/update?commit=true' --data-binary '[
{"id":"A","foo": 7, "out_edge":["B","C"] },
{"id":"B","foo": 12, "out_edge":["E","D"] },
{"id":"C","foo": 10, "out_edge":["A","D"] },
{"id":"D","foo": 20, "out_edge":["A","F"] },
{"id":"E","foo": 17, "out_edge":[] },
{"id":"F","foo": 11, "out_edge":[] },
{"id":"G","foo": 7, "out_edge":["H"] },
{"id":"H","foo": 10, "out_edge":[] }
]'
Apache Solr Reference Guide 6.0
286