Shortest Path Queries

How to do shortest path queries using the Python client

The shortest path between an object a and an object b via a predicate p can achieved with the use of a path query.

This example uses the DBPedia database which can be cloned from TerminusHub. It gives the shortest path between band members of Whitesnake, bands that these members have been in, the members of these bands, the bands that these members have been in, etc. until finally, we arrive at a band that plays Country music (a 6 hop path).

In Python:

#!/usr/bin/python3

import os
import time
import datetime
from terminusdb_client import WOQLClient
from terminusdb_client import WOQLQuery as WOQL

# Connect to the server
server_url = "http://127.0.0.1:6363"
db = "dbpedia_1"
user = "admin"
account = "admin"
key = "root"
client = WOQLClient(server_url)
client.connect(user=user, account=account, key=key, db=db)

query = WOQL().limit(1,
      WOQL.woql_and(
        WOQL().path("Whitesnake", "(bandMember>,<bandMember)+", "v:Band","v:Path"),
        WOQL().triple("v:Band", "genre", "Country_music"),
    ))
result = client.query(query)
print(result['bindings'][0]['Band'])
print(result['bindings'][0]['Path'])

The answer we obtain for the band is Angelfire_(band) with the path:

"Whitesnake" - "bandMember" -> "Reb_Beach"
"Winger_(band)" - "bandMember" -> "Reb_Beach"
"Winger_(band)" - "bandMember" -> "Rod_Morgenstein"
"Dixie_Dregs" - "bandMember" -> "Rod_Morgenstein"
"Dixie_Dregs" - "bandMember" -> "Steve_Morse"
"Angelfire_(band)"- "bandMember" -> "Steve_Morse"