The Python interface to the Trovares xGT graph analytics engine.
Main Features¶
Data loading
xGT is a strongly-typed graph system. Loading data is a two-step process:
Describe the structure and data types of your graph.
Define the vertex and edge frame structure with Connection.create_vertex_frame() and Connection.create_edge_frame(). Once the type structure is set, VertexFrame and EdgeFrame objects provide access to the server-side structures.
Load your edge and vertex data.
The VertexFrame and EdgeFrame objcts provide high-performance, parallel load() methods to ingest data as well as a direct insert() method to add small amounts of data piecewise.
Query processing
Queries are expressed as strings written in TQL.
>>> query = '''
MATCH (emp:Employee)-[edge1:ReportsTo]->(boss:Employee)
RETURN emp.person_id AS employee_id,
boss.person_id AS boss_id
INTO ResultTable
'''
A query runs in the context of a Job, which can be run, scheduled and canceled. The run_job() method runs the query and blocks until it finishes successfully, terminates by an error, or it’s canceled.
Example
The following Python script shows some of the functions that can be used to create a graph, load data into it, run a query and access the results, and finally remove that graph from the system.
import xgt
# Connect to xgtd
conn = xgt.Connection()
# Define and create the graph
employees = conn.create_vertex_frame(
name='Employees',
schema=[['person_id', xgt.INT],
['name', xgt.TEXT],
['postal_code', xgt.INT]],
key='person_id')
reports_to = conn.create_edge_frame(
name='ReportsTo',
schema=[['employee_id', xgt.INT],
['boss_id', xgt.INT],
['start_date', xgt.DATE],
['end_date', xgt.DATE]],
source=employees,
target=employees,
source_key='employee_id',
target_key='boss_id')
# Load data to the graph in xgtd
# Use the insert() method for data of a few hundred rows or less;
# for bigger amounts of data, use the load() method with csv files.
employees.insert(
[[111111101, 'Manny', 98103],
[111111102, 'Trish', 98108],
[911111501, 'Frank', 98101],
[911111502, 'Alice', 98102]
])
reports_to.insert(
[[111111101, 911111501, '2015-01-03', '2017-04-14'],
[111111102, 911111501, '2016-04-02', '2017-04-14'],
[911111502, 911111501, '2016-07-07', '2017-04-14'],
[111111101, 911111502, '2017-04-15', '3000-12-31'],
[111111102, 911111502, '2017-04-15', '3000-12-31'],
[911111501, 911111502, '2017-04-15', '3000-12-31']
])
# Query data
cmd = '''
MATCH
(employee:Employees)-[edge1:ReportsTo]->
(boss:Employees)-[edge2:ReportsTo]->
(employee)
WHERE
edge1.end_date <= edge2.start_date
RETURN
employee.person_id AS employee1_id,
boss.person_id AS employee2_id,
edge1.start_date AS start1,
edge1.end_date AS end1,
edge2.start_date AS start2,
edge2.end_date AS end2
INTO
Results
'''
conn.drop_frame('Results')
conn.run_job(cmd)
results = conn.get_table_frame('Results')
# Results extraction
for frame in [employees, reports_to, results]:
print('{name}: {n_cols} columns, {n_rows} rows'.format(
name=frame.name,
n_cols=len(frame.schema),
n_rows=frame.num_rows))
print('\n--- Results ---')
for row in results.get_data(0,100):
print(', '.join([str(c) for c in row]))
# Drop all objects
[conn.drop_frame(f) for f in [reports_to, employees, results]]