The best way to connect to an external data store from Domino is to use a Domino connector to create a Domino data source. However, you also have the option to connect to an external data store directly from a Domino application. Because Domino can run any user-produced code, you can always execute code that connects to any data source you wish. As long as the Domino executor machines have network connectivity to your data, Domino will run the code.
Common use cases for directly accessing external data include pulling data from APIs, accessing a database without going through a Domino connector, or accessing a network-based file store without going through an External Data Volume (EDV).
The general procedure is as follows:
Install the package for the data store in your environment or in your workspace session.
Set up the credentials for the data store.
Be sure to store your credentials securely and use environment variables to access them in your code. See Secure credential storage.
Fetch data from the data store.
The method for fetching data depends on the data store.