27.9.1 Setting and Getting Property Values

Getting Property Values

You can obtain the vertex or edge property values by executing a SELECT PGQL query on the graph.

For example:

• JShell
• Java

opg4j> session.queryPgql("SELECT e.src_id, e.dest_id, e.amount FROM MATCH (n:Account) -[e:Transfers]-> (m:Account) on bank_graph").print()

...
...
PgxGraph g = session.getGraph("bank_graph");
String query =
    "SELECT e.src_id, e.dest_id, e.amount FROM MATCH (n:Account) -[e:Transfers]-> (m:Account)";
g.queryPgql(query).print();

The resulting property values may appear as:

+---------------------------+
| src_id | dest_id | amount |
+---------------------------+
| 1      | 259     | 1000   |
| 1      | 418     | 1000   |
| 1      | 584     | 1000   |
| 1      | 644     | 1000   |
| 1      | 672     | 1000   |
| 2      | 493     | 1000   |
| 2      | 546     | 1000   |
| 2      | 693     | 1000   |
| 2      | 833     | 1000   |
| 2      | 840     | 1000   |
+---------------------------+

Setting Property Values

You can set the vertex or edge property values by executing insert or update PGQL queries on the graph.

For example, to set a new vertex account ID on a graph using INSERT query:

• JShell
• Java

opg4j> PgxGraph g = session.getGraph("bank_graph_analytics")
g ==> PgxGraph[name=bank_graph_analytics,N=1000,E=5001,created=1616312153556]
opg4j> PgxGraph g_mutable = g.clone("bank_graph_analytics_copy")
g_mutable ==> PgxGraph[name=bank_graph_analytics_copy,N=1000,E=5001,created=1616312413799]
opg4j> g_mutable.executePgql("INSERT VERTEX v LABELS (Accounts) PROPERTIES ( v.id = 1001)")

...
...
PgxGraph g1 = session.readGraphWithProperties("bank_graph_analytics.json");
PgxGraph g2 = g1.clone("bank_graph_analytics_copy");
g2.executePgql("INSERT VERTEX v " +
               "         LABELS ( Accounts ) " +
               "         PROPERTIES ( v.id = 1001 )");