Ontorefine导入PostgreSQL数据及GraphDD 9.5 Free查询无数据问题求助

Hey there! Let’s break down your two questions with clear, actionable steps—first covering OntoRefine PostgreSQL imports, then troubleshooting that tricky GraphDB issue.

Getting data from PostgreSQL into OntoRefine is straightforward once you know the steps:

• Start a new project with database data
  Launch OntoRefine, click Create Project, then select the Database (or "Get data from Database") option from the menu.
• Configure your PostgreSQL connection
  Fill in the connection details carefully:
  • Database type: Pick PostgreSQL from the dropdown
  • Host: Use localhost if PostgreSQL is on the same machine; otherwise, enter your server’s IP address
  • Port: Default is 5432—double-check your PostgreSQL config if you’ve changed this
  • Database name: The exact name of your target PostgreSQL database
  • Username/Password: Credentials that have read access to the database
  • (Optional) JDBC URL: If you need custom settings, use a full string like jdbc:postgresql://localhost:5432/your_database_name
• Test and select your data
  Click Test Connection to confirm everything’s working. Once connected, you have two options:
  • Run a custom SELECT query to fetch specific data (e.g., SELECT * FROM public.your_table LIMIT 100 to avoid loading too much at once)
  • Choose a table directly from the dropdown to import all its content
• Import and refine
  Hit Import to load the data into OntoRefine. You’ll land in the project workspace where you can clean, transform, and shape your dataset as needed.

It’s frustrating when a connection works but queries hang or return nothing—let’s dig into the most likely fixes:

• Double-check your query and data
  First, confirm the data actually exists! Run the exact same SELECT query in a PostgreSQL client like pgAdmin. If there’s no data there, that’s the issue. Also, make sure you’re targeting the right schema (PostgreSQL uses public by default, so add it if needed: SELECT * FROM public.your_table;).
• Verify PostgreSQL user permissions
  Even if the connection succeeds, the user GraphDB is using might not have read access to the table. Fix this by running this in PostgreSQL:

  GRANT SELECT ON public.your_table TO your_graphdb_user;
  

• Check GraphDB’s JDBC setup
  • Ensure you’re using a compatible JDBC driver for PostgreSQL 13. GraphDB 9.5 should include one, but if not, download the PostgreSQL JDBC JAR (version 42.2.x or higher) and drop it into GraphDB’s lib folder, then restart the service.
  • Review your connection URL for missing parameters. For example, if SSL isn’t enabled on PostgreSQL, add ?sslmode=disable to the end of the URL to avoid hangs.
• Rule out Windows firewall/network issues
  Windows Firewall might block traffic after the initial connection handshake. Try temporarily disabling it to test—if that fixes things, add exceptions for both GraphDB and PostgreSQL in your firewall settings.
  Also, check PostgreSQL’s pg_hba.conf file (usually in C:\Program Files\PostgreSQL\13\data\) to make sure it allows connections from your GraphDB machine. Look for an entry like host all all 127.0.0.1/32 md5 if it’s a local connection.
• Check GraphDB logs for clues
  GraphDB’s log files (found in C:\Program Files\Ontotext\GraphDB Free\logs on Windows) often have hidden error messages about timeouts, permission issues, or driver problems. Take a look—they’ll usually point you to the root cause.

内容的提问来源于stack exchange，提问作者ANA MARIA