Connect to Live AlloyDB Data in PostGresSQL Interface through CData Connect Cloud

There are a vast number of PostgreSQL clients available on the Internet. PostgreSQL is a popular interface for data access. When you pair PostgreSQL with CData Connect Cloud, you gain database-like access to live AlloyDB data from PostgreSQL. In this article, we walk through the process of connecting to AlloyDB data in Connect Cloud and establishing a connection between Connect Cloud and PostgreSQL using a TDS foreign data wrapper (FDW).

CData Connect Cloud provides a pure SQL Server interface for AlloyDB, allowing you to query data from AlloyDB without replicating the data to a natively supported database. Using optimized data processing out of the box, CData Connect Cloud pushes all supported SQL operations (filters, JOINs, etc.) directly to AlloyDB, leveraging server-side processing to return the requested AlloyDB data quickly.

Connect to AlloyDB in Connect Cloud

CData Connect Cloud uses a straightforward, point-and-click interface to connect to data sources.

1. Log into Connect Cloud, click Connections and click Add Connection
2. Select "AlloyDB" from the Add Connection panel
3. Enter the necessary authentication properties to connect to AlloyDB.

   The following connection properties are usually required in order to connect to AlloyDB.

   • Server: The host name or IP of the server hosting the AlloyDB database.
   • User: The user which will be used to authenticate with the AlloyDB server.
   • Password: The password which will be used to authenticate with the AlloyDB server.

   You can also optionally set the following:

   • Database: The database to connect to when connecting to the AlloyDB Server. If this is not set, the user's default database will be used.
   • Port: The port of the server hosting the AlloyDB database. This property is set to 5432 by default.

   Authenticating with Standard Authentication

   Standard authentication (using the user/password combination supplied earlier) is the default form of authentication.

   No further action is required to leverage Standard Authentication to connect.

   Authenticating with pg_hba.conf Auth Schemes

   There are additional methods of authentication available which must be enabled in the pg_hba.conf file on the AlloyDB server.

   Find instructions about authentication setup on the AlloyDB Server here.

   Authenticating with MD5 Authentication

   This authentication method must be enabled by setting the auth-method in the pg_hba.conf file to md5.

   Authenticating with SASL Authentication

   This authentication method must be enabled by setting the auth-method in the pg_hba.conf file to scram-sha-256.

   Authenticating with Kerberos

   The authentication with Kerberos is initiated by AlloyDB Server when the ∏ is trying to connect to it. You should set up Kerberos on the AlloyDB Server to activate this authentication method. Once you have Kerberos authentication set up on the AlloyDB Server, see the Kerberos section of the help documentation for details on how to authenticate with Kerberos.

4. Click Create & Test
5. Navigate to the Permissions tab in the Add AlloyDB Connection page and update the User-based permissions.

Add a Personal Access Token

If you are connecting from a service, application, platform, or framework that does not support OAuth authentication, you can create a Personal Access Token (PAT) to use for authentication. Best practices would dictate that you create a separate PAT for each service, to maintain granularity of access.

1. Click on your username at the top right of the Connect Cloud app and click User Profile.
2. On the User Profile page, scroll down to the Personal Access Tokens section and click Create PAT.
3. Give your PAT a name and click Create.
4. The personal access token is only visible at creation, so be sure to copy it and store it securely for future use.

Build the TDS Foreign Data Wrapper

The Foreign Data Wrapper can be installed as an extension to PostgreSQL, without recompiling PostgreSQL. The tds_fdw extension is used as an example (https://github.com/tds-fdw/tds_fdw).

1. You can clone and build the git repository via something like the following view source: sudo apt-get install git git clone https://github.com/tds-fdw/tds_fdw.git cd tds_fdw make USE_PGXS=1 sudo make USE_PGXS=1 install Note: If you have several PostgreSQL versions and you do not want to build for the default one, first locate where the binary for pg_config is, take note of the full path, and then append PG_CONFIG= after USE_PGXS=1 at the make commands.
2. After you finish the installation, then start the server: sudo service postgresql start
3. Then go inside the Postgres database psql -h localhost -U postgres -d postgres Note: Instead of localhost you can put the IP where your PostgreSQL is hosted.

Connect to AlloyDB data as a PostgreSQL Database and query the data!

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

1. Log into your database.
2. Load the extension for the database: CREATE EXTENSION tds_fdw;
3. Create a server object for AlloyDB data: CREATE SERVER "AlloyDB1" FOREIGN DATA WRAPPER tds_fdw OPTIONS (servername'tds.cdata.com', port '14333', database 'AlloyDB1');
4. Configure user mapping with your email and Personal Access Token from your Connect Cloud account: CREATE USER MAPPING for postgres SERVER "AlloyDB1" OPTIONS (username 'username@cdata.com', password 'your_personal_access_token' );
5. Create the local schema: CREATE SCHEMA "AlloyDB1";
6. Create a foreign table in your local database: #Using a table_name definition: CREATE FOREIGN TABLE "AlloyDB1".Orders ( id varchar, ShipCity varchar) SERVER "AlloyDB1" OPTIONS(table_name 'AlloyDB.Orders', row_estimate_method 'showplan_all'); #Or using a schema_name and table_name definition: CREATE FOREIGN TABLE "AlloyDB1".Orders ( id varchar, ShipCity varchar) SERVER "AlloyDB1" OPTIONS (schema_name 'AlloyDB', table_name 'Orders', row_estimate_method 'showplan_all'); #Or using a query definition: CREATE FOREIGN TABLE "AlloyDB1".Orders ( id varchar, ShipCity varchar) SERVER "AlloyDB1" OPTIONS (query 'SELECT * FROM AlloyDB.Orders', row_estimate_method 'showplan_all'); #Or setting a remote column name: CREATE FOREIGN TABLE "AlloyDB1".Orders ( id varchar, col2 varchar OPTIONS (column_name 'ShipCity')) SERVER "AlloyDB1" OPTIONS (schema_name 'AlloyDB', table_name 'Orders', row_estimate_method 'showplan_all');
7. You can now execute read/write commands to AlloyDB: SELECT id, ShipCity FROM "AlloyDB1".Orders;

More Information & Free Trial

Now, you have created a simple query from live AlloyDB data. For more information on connecting to AlloyDB (and more than 100 other data sources), visit the Connect Cloud page. Sign up for a free trial and start working with live AlloyDB data in PostgreSQL.