Create ASP.NET Core Web API with postgresql without using EF

Hi friends,

   Now i am learning to create asp.net core web API with postgresql.I refered lot about creating web api,but many of the article using entity framework. I like to create a connection string of postgresql and perform crud operation in asp.net core web api without using entity framework and also I want to access connection string inside api controller.

 

Please help to create a web api without entity framework. I hope you can understand my question