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

Connect to Azure Data Catalog Data as a JDBC Data Source

To connect to Azure Data Catalog 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.azuredatacatalog.AzureDataCatalogDriver
  

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

  You can optionally set the following to read the different catalog data returned from Azure Data Catalog.

  <>CatalogName: Set this to the CatalogName associated with your Azure Data Catalog. To get your Catalog name, navigate to your Azure Portal home page > Data Catalog > Catalog Name

  Connect Using OAuth Authentication

  You must use OAuth to authenticate with Azure Data Catalog. OAuth requires the authenticating user to interact with Azure Data Catalog using the browser. For more information, refer to the OAuth section in the help documentation.

  Built-in Connection String Designer

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

  java -jar cdata.jdbc.azuredatacatalog.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:azuredatacatalog:InitiateOAuth=GETANDREFRESH;
  

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 Azure Data Catalog Data as a PostgreSQL Database

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

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

   CREATE EXTENSION jdbc2_fdw;
   

3. Create a server object for Azure Data Catalog:

   CREATE SERVER AzureDataCatalog 
   FOREIGN DATA WRAPPER jdbc2_fdw OPTIONS (
   drivername 'cdata.jdbc.azuredatacatalog.AzureDataCatalogDriver',
   url 'jdbc:azuredatacatalog:InitiateOAuth=GETANDREFRESH;',
   querytimeout '15',
   jarfile '/home/MyUser/CData/CData\ JDBC\ Driver\ for\ Salesforce MyDriverEdition/lib/cdata.jdbc.azuredatacatalog.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 AzureDataCatalog OPTIONS (
   username 'admin', 
   password 'test');
   

5. Create a foreign table in your local database:

   postgres=# CREATE FOREIGN TABLE tables (
   tables_id text,
   tables_DslAddressDatabase text,
   tables_Type numeric) 
   SERVER AzureDataCatalog OPTIONS (
   table_name 'tables');
   

You can now execute SELECT commands to Azure Data Catalog:

postgres=# SELECT * FROM tables;