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

Connect to xBase Data as a JDBC Data Source

To connect to xBase 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.xbase.xBaseDriver
  

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

  The DataSource property must be set to the name of the folder that contains the .dbf files. Specify the IncludeFiles property to work with xBase table files having extensions that differ from .dbf. Specify multiple extensions in a comma-separated list.

  Built-in Connection String Designer

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

  java -jar cdata.jdbc.xbase.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:xbase:DataSource=MyDBFFilesFolder;
  

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 xBase Data as a PostgreSQL Database

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

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

   CREATE EXTENSION jdbc2_fdw;
   

3. Create a server object for xBase:

   CREATE SERVER xBase 
   FOREIGN DATA WRAPPER jdbc2_fdw OPTIONS (
   drivername 'cdata.jdbc.xbase.xBaseDriver',
   url 'jdbc:xbase:DataSource=MyDBFFilesFolder;',
   querytimeout '15',
   jarfile '/home/MyUser/CData/CData\ JDBC\ Driver\ for\ Salesforce MyDriverEdition/lib/cdata.jdbc.xbase.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 xBase OPTIONS (
   username 'admin', 
   password 'test');
   

5. Create a foreign table in your local database:

   postgres=# CREATE FOREIGN TABLE invoices (
   invoices_id text,
   invoices_Company text,
   invoices_Total numeric) 
   SERVER xBase OPTIONS (
   table_name 'invoices');
   

You can now execute SELECT commands to xBase:

postgres=# SELECT * FROM invoices;