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

Connect to MySQL Data as a JDBC Data Source

To connect to MySQL 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.mysql.MySQLDriver
  

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

  The CData Provider supports connecting to on-premises and cloud-hosted versions of MySQL such as Amazon RDS for MySQL, Google Cloud SQL for MySQL, Azure Database for MySQL, or Oracle MySQL HeatWave. The Server and Port properties must be set to a MySQL server. If IntegratedSecurity is set to false, then User and Password must be set to valid user credentials. Optionally, Database can be set to connect to a specific database. If not set, tables from all databases will be returned.

  SSH Connectivity for MySQL

  You can use SSH (Secure Shell) to authenticate with MySQL, whether the instance is hosted on-premises or in supported cloud environments. SSH authentication ensures that access is encrypted (as compared to direct network connections).

  SSH Connections to MySQL in Password Auth Mode

  To connect to MySQL via SSH in Password Auth mode, set the following connection properties:

  • User: MySQL User name
  • Password: MySQL Password
  • Database: MySQL database name
  • Server: MySQL Server name
  • Port: MySQL port number like 3306
  • UserSSH: "true"
  • SSHAuthMode: "Password"
  • SSHPort: SSH Port number
  • SSHServer: SSH Server name
  • SSHUser: SSH User name
  • SSHPassword: SSH Password

  SSH Connections to MySQL in Public Key Auth Mode

  To connect to MySQL via SSH in Password Auth mode, set the following connection properties:

  • User: MySQL User name
  • Password: MySQL Password
  • Database: MySQL database name
  • Server: MySQL Server name
  • Port: MySQL port number like 3306
  • UserSSH: "true"
  • SSHAuthMode: "Public_Key"
  • SSHPort: SSH Port number
  • SSHServer: SSH Server name
  • SSHUser: SSH User name
  • SSHClientCret: the path for the public key certificate file

  Built-in Connection String Designer

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

  java -jar cdata.jdbc.mysql.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:mysql:User=myUser;Password=myPassword;Database=NorthWind;Server=myServer;Port=3306;
  

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 MySQL Data as a PostgreSQL Database

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

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

   CREATE EXTENSION jdbc2_fdw;
   

3. Create a server object for MySQL:

   CREATE SERVER MySQL 
   FOREIGN DATA WRAPPER jdbc2_fdw OPTIONS (
   drivername 'cdata.jdbc.mysql.MySQLDriver',
   url 'jdbc:mysql:User=myUser;Password=myPassword;Database=NorthWind;Server=myServer;Port=3306;',
   querytimeout '15',
   jarfile '/home/MyUser/CData/CData\ JDBC\ Driver\ for\ Salesforce MyDriverEdition/lib/cdata.jdbc.mysql.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 MySQL OPTIONS (
   username 'admin', 
   password 'test');
   

5. Create a foreign table in your local database:

   postgres=# CREATE FOREIGN TABLE orders (
   orders_id text,
   orders_ShipName text,
   orders_Freight numeric) 
   SERVER MySQL OPTIONS (
   table_name 'orders');
   

You can now execute read/write commands to MySQL:

postgres=# SELECT * FROM orders;