The four main HTTP methods (GET, PUT, POST, PATCH and DELETE) can be mapped to CRUD operations as follows:
Enabling OData Query Options
Web API supports the following OData query options:
Using $select, $expand, and $value in Web API
Web API 2 adds support for the $expand, $select, and $value options in OData. These options allow a client to control the representation that it gets back from the server.
$expand causes related entities to be included inline in the response.
$select selects a subset of properties to include in the response.
$value gets the raw value of a property.
The ASP.NET Web API is a framework for building web APIs on top of the .NET framework. It uses HTTP as an application protocol (rather than a transport protocol) to return data based on the client requests. The Web API is able to return the data appropriately based on the media type specified with the request. By default it provides JSON based responses. CRUD stands for "Create, Read, Update, and Delete," which are the four basic database operations. Many HTTP services also model CRUD operations through REST or REST-like APIs.