6.9.1.5.3 Basic Query Execution

You can execute PGQL queries using the opg4py.pgql Python wrapper.

Executing PGQL Queries Using the Python Client

• Set the graph for querying as shown:

  >>> pgql_conn.set_graph("<graph_name>")
  

  where <graph_name> is the name of the graph.

• Define and execute the PGQL SELECT query. For example,

  >>> pgql = "SELECT e.from_acct_id, e.to_acct_id, e.amount FROM MATCH (n:accounts) -[e:transfers]-> (m:accounts) on bank_graph limit 10"
  

• Execute and print the result set as shown:

  >>> pgql_result_set = pgql_statement.execute_query(pgql)
  >>> pgql_result_set.print()
  +------------------------------------+
  | FROM_ACCT_ID | TO_ACCT_ID | AMOUNT |
  +------------------------------------+
  | 781.0        | 712.0      | 1000.0 |
  | 190.0        | 555.0      | 1000.0 |
  | 191.0        | 329.0      | 1000.0 |
  | 198.0        | 57.0       | 1000.0 |
  | 220.0        | 441.0      | 1000.0 |
  | 251.0        | 387.0      | 1000.0 |
  | 254.0        | 188.0      | 1000.0 |
  | 259.0        | 305.0      | 1000.0 |
  | 261.0        | 145.0      | 1000.0 |
  | 263.0        | 40.0       | 1000.0 |
  +------------------------------------+
  
  PgqlResultSet(java_pgql_result_set: oracle.pg.rdbms.pgql.PgqlResultSet, # of results: 0)
  
  

Also, you can convert the PGQL result set obtained in the preceding code to a Pandas dataframe using the to_pandas() method.

Note:

The pandas package must be installed in your system to successfully execute the call to to_pandas(). This package is automatically installed at the time of the Python client installation for versions Python 3.8 and Python 3.9. However, if your call to to_pandas() fails, verify if the pandas module is installed in your system. In case the module is found missing or your Python version differs from the earlier mentioned versions, then install the pandas package manually.