What is OLE DB in SQL Server?

Database

OLE DB (Object Linking and Embedding, Database, sometimes written as OLEDB or OLE-DB), an API designed by Microsoft, allows accessing data from a variety of sources in a uniform manner. The API provides a set of interfaces implemented using the Component Object Model (COM); it is otherwise unrelated to OLE.

Read More: https://www.connectionstrings.com/sql-server-native-client-11-0-oledb-provider/