Build a PostgreSQL Interface for Exa 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 Exa data as a PostgreSQL database, use the CData JDBC Driver for Exa and a JDBC foreign data wrapper (FDW). In this article, we compile the FDW, install it, and query Exa data from PostgreSQL Server.

Connect to Exa Data as a JDBC Data Source

To connect to Exa 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.api.APIDriver
  

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

  Start by setting the Profile connection property to the location of the Exa Profile on disk (e.g. C:\profiles\Exa.apip). Next, set the ProfileSettings connection property to the connection string for Exa (see below).

  Exa API Profile Settings

  Visit dashboard.exa.ai, sign in or create an account, and generate an API key from your API settings.

  Built-in Connection String Designer

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

  java -jar cdata.jdbc.api.jar
  

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

  

  A typical JDBC URL is below:

  jdbc:api:Profile=C:\profiles\Exa.apip;ProfileSettings='APIKey=your_api_key';
  

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 Exa Data as a PostgreSQL Database

After you have installed the extension, follow the steps below to start executing queries to Exa data:

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

   CREATE EXTENSION jdbc2_fdw;
   

3. Create a server object for Exa:

   CREATE SERVER API 
   FOREIGN DATA WRAPPER jdbc2_fdw OPTIONS (
   drivername 'cdata.jdbc.api.APIDriver',
   url 'jdbc:api:Profile=C:\profiles\Exa.apip;ProfileSettings='APIKey=your_api_key';',
   querytimeout '15',
   jarfile '/home/MyUser/CData/CData\ JDBC\ Driver\ for\ Salesforce MyDriverEdition/lib/cdata.jdbc.api.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 API OPTIONS (
   username 'admin', 
   password 'test');
   

5. Create a foreign table in your local database:

   postgres=# CREATE FOREIGN TABLE answer (
   answer_id text,
   answer_RequestId text,
   answer_Answer numeric) 
   SERVER API OPTIONS (
   table_name 'answer');
   

postgres=# SELECT * FROM answer;