Access PostgreSQL Data in Mule Applications Using the CData JDBC Driver

The CData JDBC Driver for PostgreSQL connects PostgreSQL data to Mule applications enabling read , write, update, and delete functionality with familiar SQL queries. The JDBC Driver allows users to easily create Mule applications to backup, transform, report, and analyze PostgreSQL data.

This article demonstrates how to use the CData JDBC Driver for PostgreSQL inside of a Mule project to create a Web interface for PostgreSQL data. The application created allows you to request PostgreSQL data using an HTTP request and have the results returned as JSON. The exact same procedure outlined below can be used with any CData JDBC Driver to create a Web interface for the hundreds of available data sources.

1. Create a new Mule Project in Anypoint Studio.
2. Add an HTTP Connector to the Message Flow.
3. Configure the address for the HTTP Connector. 👁 Add and Configure the HTTP Connector
   
4. Add a Database Select Connector to the same flow, after the HTTP Connector.
5. Create a new Connection (or edit an existing one) and configure the properties.
   • Set Connection to "Generic Connection"
   • Select the CData JDBC Driver JAR file in the Required Libraries section (e.g. cdata.jdbc.postgresql.jar). 👁 Adding the JAR file (Salesforce is shown).
     
   • Set the URL to the connection string for PostgreSQL

     To connect to PostgreSQL, set the Server, Port (the default port is 5432), and Database connection properties and set the User and Password you wish to use to authenticate to the server. If the Database property is not specified, the data provider connects to the user's default database.

     SSH Connectivity for PostgreSQL

     You can use SSH (Secure Shell) to authenticate with PostgreSQL, whether the instance is hosted on-premises or in supported cloud environments. SSH authentication ensures that access is encrypted (as compared to direct network connections).

     SSH Connections to PostgreSQL in Password Auth Mode

     To connect to PostgreSQL via SSH in Password Auth mode, set the following connection properties:

     • User: PostgreSQL User name
     • Password: PostgreSQL Password
     • Database: PostgreSQL database name
     • Server: PostgreSQL Server name
     • Port: PostgreSQL port number like 3306
     • UserSSH: "true"
     • SSHAuthMode: "Password"
     • SSHPort: SSH Port number
     • SSHServer: SSH Server name
     • SSHUser: SSH User name
     • SSHPassword: SSH Password

     SSH Connections to PostgreSQL in Public Key Auth Mode

     To connect to PostgreSQL via SSH in Password Auth mode, set the following connection properties:

     • User: PostgreSQL User name
     • Password: PostgreSQL Password
     • Database: PostgreSQL database name
     • Server: PostgreSQL Server name
     • Port: PostgreSQL port number like 3306
     • UserSSH: "true"
     • SSHAuthMode: "Public_Key"
     • SSHPort: SSH Port number
     • SSHServer: SSH Server name
     • SSHUser: SSH User name
     • SSHClientCret: the path for the public key certificate file

     Built-in Connection String Designer

     For assistance in constructing the JDBC URL, use the connection string designer built into the PostgreSQL JDBC Driver. Either double-click the JAR file or execute the jar file from the command-line.

     		java -jar cdata.jdbc.postgresql.jar
     		

     Fill in the connection properties and copy the connection string to the clipboard.

   • Set the Driver class name to cdata.jdbc.postgresql.PostgreSQLDriver. 👁 A configured Database Connection (Salesforce is shown).
     
   • Click Test Connection.
6. Set the SQL Query Text to a SQL query to request PostgreSQL data. For example:

   SELECT ShipName, ShipCity FROM Orders

   👁 Configure the Select object (Salesforce is Shown)
   
7. Add a Transform Message Component to the flow.
8. Set the Output script to the following to convert the payload to JSON:

   %dw 2.0
   output application/json
   ---
   payload
    

   👁 Add the Transform Message Component to the Flow
   
9. To view your PostgreSQL data, navigate to the address you configured for the HTTP Connector (localhost:8081 by default): http://localhost:8081. The PostgreSQL data is available as JSON in your Web browser and any other tools capable of consuming JSON endpoints.

At this point, you have a simple Web interface for working with PostgreSQL data (as JSON data) in custom apps and a wide variety of BI, reporting, and ETL tools. Download a free, 30 day trial of the JDBC Driver for PostgreSQL and see the CData difference in your Mule Applications today.