5.4.8 Opening and Closing a Property Graph Instance

When describing a property graph, use these Oracle Property Graph classes to open and close the property graph instance properly:

• OraclePropertyGraph.getInstance: Opens an instance of an Oracle property graph. This method has two parameters, the connection information and the graph name. The format of the connection information depends on whether you use HBase or Oracle NoSQL Database as the backend database.

• OraclePropertyGraph.clearRepository: Removes all vertices and edges from the property graph instance.

• OraclePropertyGraph.shutdown: Closes the graph instance.

For Oracle Database, the OraclePropertyGraph.getInstance method uses an Oracle instance to manage the database connection. OraclePropertyGraph has a set of constructors that let you set the graph name, number of hash partitions, degree of parallelism, tablespace, and options for storage (such as compression). For example:

import oracle.pg.rdbms.*;
Oracle oracle = new Oracle(jdbcURL, username, password);

OraclePropertyGraph opg = OraclePropertyGraph.getInstance(oracle, graphName);
opg.clearRepository(); 
//     .
//     .  Graph description
//     .
// Close the graph instance
opg.shutdown();

If the in-memory analyst functions are required for an application, you should use GraphConfigBuilder to create a graph for Oracle Database, and instantiate OraclePropertyGraph with that graph name as an argument. For example, the following code snippet constructs a graph config, gets an OraclePropertyGraph instance, loads some data into that graph, and gets an in-memory analyst.

import oracle.pgx.config.*;
import oracle.pgx.api.*;
import oracle.pgx.common.types.*;

...
 
PgNosqlGraphConfig cfg = GraphConfigBuilder. forPropertyGraphRdbms ()
       .setJdbcUrl("jdbc:oracle:thin:@<hostname>:1521:<sid>")
       .setUsername("<username>").setPassword("<password>")
       .setName(szGraphName)
       .setMaxNumConnections(8)
       .addEdgeProperty("lbl", PropertyType.STRING, "lbl")
       .addEdgeProperty("weight", PropertyType.DOUBLE, "1000000")
       .build();
 
  OraclePropertyGraph opg = OraclePropertyGraph.getInstance(cfg);  
 
  String szOPVFile = "../../data/connections.opv";
  String szOPEFile = "../../data/connections.ope";
 
  // perform a parallel data load
  OraclePropertyGraphDataLoader opgdl = OraclePropertyGraphDataLoader.getInstance();
  opgdl.loadData(opg, szOPVFile, szOPEFile, 2 /* dop */, 1000, true, "PDML=T,PDDL=T,NO_DUP=T,"); 
 
  ...
  PgxSession session = Pgx.createSession("session-id-1");
  PgxGraph g = session.readGraphWithProperties(cfg);

  Analyst analyst = session.createAnalyst();
  ...