This chapter describes in detail about working with different file formats to perform various actions like loading, storing, or exporting a graph using the Graph Server (PGX).

In order to read or write files, you need to explicitly authorize access to the corresponding directories by defining a directory object pointing to the directory (on the graph server) that contains the files to read or write.

CREATE OR REPLACE DIRECTORY graph_files AS '/data/graphs/my_graphs';
GRANT READ, WRITE ON DIRECTORY graph_files TO GRAPH_DEVELOPER;

Also, note the following:

• The directory in the CREATE DIRECTORY statement must exist on the graph server (PGX).
• The directory must be readable (and/or writable) at the OS level by the graph server (PGX).

The preceding code grants the privileges on the directory to the GRAPH_DEVELOPER role. However, you can also grant permissions to an individual user:

GRANT READ ON DIRECTORY graph_files TO <graph_user>;

• Loading Graph Data from Files
  
• Loading Graph Data in Parallel from Multiple Files
  
• Exporting Graphs Into a File
  
• Exporting a Graph into Multiple Files