Welcome to OPG4Py 24.1.0 documentation!

Example application

Create a python app python_app.py with the following content:

import sys

jdbc_url = sys.argv[1]
base_url = sys.argv[2]
username = sys.argv[3]
password = sys.argv[4]


# 2 tier example: run PGQL against database
import opg4py

pgql_connection = opg4py.pgql.get_connection(username, password, jdbc_url)
pgql_statement = pgql_connection.create_statement()

create_graph = "CREATE PROPERTY GRAPH hr_simplified VERTEX TABLES (employees LABEL employee PROPERTIES ARE ALL COLUMNS EXCEPT ( job_id, manager_id, department_id ), departments LABEL department PROPERTIES ( department_id, department_name )) EDGE TABLES ( employees AS works_for SOURCE KEY ( employee_id ) REFERENCES employees DESTINATION employees NO PROPERTIES) OPTIONS ( PG_PGQL )"

pgql_statement.execute(create_graph)
pgql_connection.set_graph("hr_simplified")

query = "SELECT label(n) AS srcLbl, label(e) AS edgeLbl, label(m) AS dstLbl, COUNT(*) FROM MATCH (n) -[e]-> (m) GROUP BY srcLbl, edgeLbl, dstLbl ORDER BY COUNT(*) DESC"

pgql_result_set = pgql_statement.execute_query(query)
pgql_result_set.print()
drop_graph = "DROP PROPERTY GRAPH hr_simplified"
pgql_statement.execute(drop_graph)

pgql_result_set.close()
pgql_statement.close()
pgql_connection.close()


# 3-tier example: connect to PGX
import pypgx as pgx
from opg4py import graph_server

instance = graph_server.get_instance(base_url, username, password)
session = instance.create_session("pypgx_example_session")
graph = session.create_graph_builder().add_edge(1, 2).add_edge(2, 3).add_edge(3, 1).build()
analyst = session.create_analyst()

triangles = analyst.count_triangles(graph, True)
print("triangles = {}".format(triangles))

rs = graph.query_pgql("select x, y, e from match (x) -[e]-> (y)")
rs.print()

session.close()

Start the Graph Server

Configure and start the graph server to which the example application can connect to. Follow the steps in the product documentation.

Test the application

Test the app using the following instruction, replacing <connect-string>, <hostname>, <username> and <password> with values matching your database and graph server installation:

python3 python_app.py "<connect-string>" "https://<hostname>:7007" "<username>" "<password>"

You should see an output like this:

+--------------------------------------------+
| SRCLBL   | EDGELBL   | DSTLBL   | COUNT(*) |
+--------------------------------------------+
| EMPLOYEE | WORKS_FOR | EMPLOYEE | 106      |
+--------------------------------------------+

triangles = 1

+---------------------------------------------------+
| x               | y               | e             |
+---------------------------------------------------+
| PgxVertex[ID=1] | PgxVertex[ID=2] | PgxEdge[ID=0] |
| PgxVertex[ID=2] | PgxVertex[ID=3] | PgxEdge[ID=1] |
| PgxVertex[ID=3] | PgxVertex[ID=1] | PgxEdge[ID=2] |
+---------------------------------------------------+

Indices and tables

API Reference