A PostgreSQL Interface for Gmail Data

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

Connect to Gmail Data as a JDBC Data Source

To connect to Gmail 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.gmail.GmailDriver

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

  There are two ways to authenticate to Gmail. Before selecting one, first ensure that you have enabled IMAP access in your Gmail account settings. See the "Connecting to Gmail" section under "Getting Started" in the installed documentation for a guide.

  The User and Password properties, under the Authentication section, can be set to valid Gmail user credentials.

  Alternatively, instead of providing the Password, you can use the OAuth authentication standard. To access Google APIs on behalf on individual users, you can use the embedded credentials or you can register your own OAuth app.

  OAuth also enables you to use a service account to connect on behalf of users in a Google Apps domain. To authenticate with a service account, you will need to register an application to obtain the OAuth JWT values.

  In addition to the OAuth values, you will need to provide the User. See the "Getting Started" chapter in the help documentation for a guide to using OAuth.

  Built-in Connection String Designer

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

  java -jar cdata.jdbc.gmail.jar

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

  A typical JDBC URL is below:

  jdbc:gmail:User=username;Password=password;

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 Gmail Data as a PostgreSQL Database

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

1. Log into your database.
2. Load the extension for the database: CREATE EXTENSION jdbc2_fdw;
3. Create a server object for Gmail: CREATE SERVER Gmail FOREIGN DATA WRAPPER jdbc2_fdw OPTIONS ( drivername 'cdata.jdbc.gmail.GmailDriver', url 'jdbc:gmail:User=username;Password=password;', querytimeout '15', jarfile '/home/MyUser/CData/CData\ JDBC\ Driver\ for\ Salesforce MyDriverEdition/lib/cdata.jdbc.gmail.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 Gmail OPTIONS ( username 'admin', password 'test');
5. Create a foreign table in your local database: postgres=# CREATE FOREIGN TABLE inbox ( inbox_id text, inbox_Subject text, inbox_Size numeric) SERVER Gmail OPTIONS ( table_name 'inbox');