Build a PostgreSQL Interface for IBM Cloud Object Storage Data using the CData JDBC Driver

There are a vast number of PostgreSQL clients available on the Internet. From standard Drivers to BI and Analytics tools, PostgreSQL is a popular interface for data access. Using our JDBC Drivers, you can now create PostgreSQL entry-points that you can connect to from any standard client.

To access IBM Cloud Object Storage data as a PostgreSQL database, use the CData JDBC Driver for IBM Cloud Object Storage and a JDBC foreign data wrapper (FDW). In this article, we compile the FDW, install it, and query IBM Cloud Object Storage data from PostgreSQL Server.

Connect to IBM Cloud Object Storage Data as a JDBC Data Source

To connect to IBM Cloud Object Storage as a JDBC data source, you will need the following:

• Driver JAR path: The JAR is located in the lib subfolder of the installation directory.

• Driver class:

  cdata.jdbc.ibmcloudobjectstorage.IBMCloudObjectStorageDriver
  

• JDBC URL: The URL must start with "jdbc:ibmcloudobjectstorage:" and can include any of the connection properties in name-value pairs separated with semicolons.

  Register a New Instance of Cloud Object Storage

  If you do not already have Cloud Object Storage in your IBM Cloud account, follow the procedure below to install an instance of SQL Query in your account:

  1. Log in to your IBM Cloud account.
  2. Navigate to the

  Connecting using OAuth Authentication

  There are certain connection properties you need to set before you can connect. You can obtain these as follows:

  API Key

  To connect with IBM Cloud Object Storage, you need an API Key. You can obtain this as follows:

  1. Log in to your IBM Cloud account.
  2. Navigate to the Platform API Keys page.
  3. On the middle-right corner click "Create an IBM Cloud API Key" to create a new API Key.
  4. In the pop-up window, specify the API Key name and click "Create". Note the API Key as you can never access it again from the dashboard.

  Cloud Object Storage CRN

  If you have multiple accounts, specify the CloudObjectStorageCRN explicitly. To find the appropriate value, you can:

  • Query the Services view. This will list your IBM Cloud Object Storage instances along with the CRN for each.
  • Locate the CRN directly in IBM Cloud. To do so, navigate to your IBM Cloud Dashboard. In the Resource List, Under Storage, select your Cloud Object Storage resource to get its CRN.

  Connecting to Data

  You can now set the following to connect to data:

  • InitiateOAuth: Set this to GETANDREFRESH. You can use InitiateOAuth to avoid repeating the OAuth exchange and manually setting the OAuthAccessToken.
  • ApiKey: Set this to your API key which was noted during setup.
  • CloudObjectStorageCRN (Optional): Set this to the cloud object storage CRN you want to work with. While the connector attempts to retrieve this automatically, specifying this explicitly is recommended if you have more than Cloud Object Storage account.

  When you connect, the connector completes the OAuth process.

  1. Extracts the access token and authenticates requests.
  2. Saves OAuth values in OAuthSettingsLocation to be persisted across connections.

  Built-in Connection String Designer

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

  java -jar cdata.jdbc.ibmcloudobjectstorage.jar
  

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

  👁 Using the built-in connection string designer to generate a JDBC URL (Salesforce is shown.)
  

  A typical JDBC URL is below:

  jdbc:ibmcloudobjectstorage:ApiKey=myApiKey;CloudObjectStorageCRN=MyInstanceCRN;Region=myRegion;OAuthClientId=MyOAuthClientId;OAuthClientSecret=myOAuthClientSecret;
  

Build the JDBC Foreign Data Wrapper

The Foreign Data Wrapper can be installed as an extension to PostgreSQL, without recompiling PostgreSQL. The jdbc2_fdw extension is used as an example (downloadable here).

1. Add a symlink from the shared object for your version of the JRE to /usr/lib/libjvm.so. For example:

   ln -s /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/server/libjvm.so /usr/lib/libjvm.so
   

2. Start the build:

   make install USE_PGXS=1
   

Query IBM Cloud Object Storage Data as a PostgreSQL Database

After you have installed the extension, follow the steps below to start executing queries to IBM Cloud Object Storage data:

1. Log into your database.
2. Load the extension for the database:

   CREATE EXTENSION jdbc2_fdw;
   

3. Create a server object for IBM Cloud Object Storage:

   CREATE SERVER IBMCloudObjectStorage 
   FOREIGN DATA WRAPPER jdbc2_fdw OPTIONS (
   drivername 'cdata.jdbc.ibmcloudobjectstorage.IBMCloudObjectStorageDriver',
   url 'jdbc:ibmcloudobjectstorage:ApiKey=myApiKey;CloudObjectStorageCRN=MyInstanceCRN;Region=myRegion;OAuthClientId=MyOAuthClientId;OAuthClientSecret=myOAuthClientSecret;',
   querytimeout '15',
   jarfile '/home/MyUser/CData/CData\ JDBC\ Driver\ for\ Salesforce MyDriverEdition/lib/cdata.jdbc.ibmcloudobjectstorage.jar'); 
   

4. Create a user mapping for the username and password of a user known to the MySQL daemon.

   CREATE USER MAPPING for postgres SERVER IBMCloudObjectStorage OPTIONS (
   username 'admin', 
   password 'test');
   

5. Create a foreign table in your local database:

   postgres=# CREATE FOREIGN TABLE objects (
   objects_id text,
   objects_Key text,
   objects_Etag numeric) 
   SERVER IBMCloudObjectStorage OPTIONS (
   table_name 'objects');
   

You can now execute SELECT commands to IBM Cloud Object Storage:

postgres=# SELECT * FROM objects;