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

Connect to ZenRows Data as a JDBC Data Source

To connect to ZenRows 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 ZenRows Profile on disk (e.g. C:\profiles\ZenRows.apip). Next, set the ProfileSettings connection property to the connection string for ZenRows (see below).

  ZenRows API Profile Settings

  To use the ZenRows API, you need to obtain an API key from your ZenRows account. Navigate to the ZenRows dashboard at app.zenrows.com and copy your API key from the account settings.

  After setting the following connection properties, you are ready to connect:

  • AuthScheme: Set this to APIKey.
  • APIKey: Set this to your ZenRows API key.

  Built-in Connection String Designer

  For assistance in constructing the JDBC URL, use the connection string designer built into the ZenRows 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\ZenRows.apip;AuthScheme=APIKey;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 ZenRows Data as a PostgreSQL Database

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

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

   
   CREATE EXTENSION jdbc2_fdw;
   

3. Create a server object for ZenRows:

   
   CREATE SERVER API 
   FOREIGN DATA WRAPPER jdbc2_fdw OPTIONS (
   drivername 'cdata.jdbc.api.APIDriver',
   url 'jdbc:api:Profile=C:\profiles\ZenRows.apip;AuthScheme=APIKey;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 amazondiscovery (
   amazondiscovery_id text,
   amazondiscovery_ProductId text,
   amazondiscovery_ProductName numeric) 
   SERVER API OPTIONS (
   table_name 'amazondiscovery');
   

postgres=# SELECT * FROM amazondiscovery;