How To Add Index On SharePoint Fields Using C#

In this article, we are going to see steps to create an index to a SharePoint field using C#. Indexing is a data structure which is used to quickly locate and access the data in the database table. The Client-Side Object Model (CSOM) is used internally for these operations.

source https://www.c-sharpcorner.com/article/how-to-add-index-on-sharepoint-fields-using-c-sharp/