Introduction to SQL Property Graphs

3 Introduction to SQL Property Graphs

You can work with SQL property graphs in any SQL based interface (such as SQL Developer, SQLPLUS, or SQLcl) or from a Java program using JDBC.

Using SQL statements, you can perform the following:

Create a SQL property graph from existing database objects in your schema, such as:
- Tables (with some exceptions as listed in Limitations of Creating a SQL Property Graph)
- Materialized views
- External tables
- Synonyms for any of the preceding database objects
Create a synonym for a SQL property graph.
Revalidate a SQL property graph.
Run graph pattern matching queries on a SQL property graph.
Drop a SQL property graph.

For example, the following figure shows the creation of a SQL property graph using the SQL Developer tool.

Figure 3-1 Using SQL Developer to Create a SQL Property Graph

Description of "Figure 3-1 Using SQL Developer to Create a SQL Property Graph"

Quick Start for Working with SQL Property Graphs
This tutorial helps you get started on creating and querying a SQL property graph.

Parent topic: SQL Property Graphs

3.1 Quick Start for Working with SQL Property Graphs

This tutorial helps you get started on creating and querying a SQL property graph.

In order to try this tutorial, ensure that you meet the following requirements:

Load the sample bank graph data provided with the graph server installation in the database tables. See Using Sample Data for Graph Analysis for more information.
You have the required privileges to create and drop a SQL property graph. See Granting System and Object Privileges for SQL Property Graphs for more information.

In the following tutorial, the examples in Step 1, Step 2, and Step 4 are performed using the SQLcl tool. However, you can run these examples using any SQL based interface.

Create a SQL property graph using the CREATE PROPERTY GRAPH DDL statement.
```
SQL> CREATE PROPERTY GRAPH bank_sql_pg
  2    VERTEX TABLES (
  3      bank_accounts
  4      KEY (id)
  5      LABEL account
  6      PROPERTIES ALL COLUMNS
  7    )
  8    EDGE TABLES (
  9      bank_txns
 10        KEY (txn_id)
 11        SOURCE KEY (from_acct_id) REFERENCES bank_accounts (id)
 12        DESTINATION KEY (to_acct_id) REFERENCES bank_accounts (id)
 13        LABEL transfer
 14        PROPERTIES ALL COLUMNS
 15*   );

Property created.
```
On execution, the bank_sql_pg graph schema object is created in the database. The graph is made up of one vertex graph element table (bank_accounts) and one edge graph element table (bank_txns).

See Creating a SQL Property Graph to learn the concepts of graph element tables, keys, labels and properties.

Run a GRAPH_TABLE query, on the newly created graph, to list all the transactions from the account with id value 816.

SQL> SELECT * FROM GRAPH_TABLE (bank_sql_pg
  2    MATCH
  3    (a IS account WHERE a.id = 816) -[e IS transfer]-> (b IS account)
  4    COLUMNS (a.id AS acc_a, e.amount AS amount, b.id AS acc_b)
  5* );

   ACC_A    AMOUNT    ACC_B
________ _________ ________
     816      4713      287
     816      8001      590
     816      4186      934
     816      3718      289
     816      4039      812

See SQL GRAPH_TABLE Queries to understand more about GRAPH_TABLE queries..

Optionally, if you have installed the graph server (PGX), then you can also visualize the preceding GRAPH_TABLE query, using the graph visualization tool.
The only difference is that you must return the vertex and edge IDs in order to visualize the vertices and edges of the GRAPH_TABLE query together with their IDs and all their labels and properties. Note that the COLUMNS clause in the following example uses the VERTEX_ID and EDGE_ID operators:

Figure 3-2 Visualizing GRAPH_TABLE Query

Description of "Figure 3-2 Visualizing GRAPH_TABLE Query"
- See Vertex and Edge Identifiers to learn more about the VERTEX_ID and EDGE_ID operators.
- See Visualizing Graph Queries on SQL Property Graphs for more details.
Drop the SQL property graph after running the graph queries.
```
SQL> drop property graph bank_sql_pg;

Property dropped.
```

Parent topic: Introduction to SQL Property Graphs