The HTTP request method: GET for read operations and POST for write operations. POST requests can perform update or delete operations by specifying a DELETE, MERGE, or PUT verb in the X-HTTP-Method header.

X-HTTP-Method header

POST requests for DELETE, MERGE, or PUT operations

Used to specify that the request performs an update or delete operation. Example: "X-HTTP-Method":"PUT"

The remainder of this section defines a custom HTTP MERGE method that is used in the OData 1.0 and OData 2.0 protocols to specify that an update is to be completed by using merge semantics. All the directives defined for the PUT method in HTTP, as specified in [RFC2616], and AtomPub, as specified in [RFC5023], apply equally to the HTTP MERGE method. The only difference between an HTTP request that uses MERGE or PATCH and PUT is client intent.

Since MERGE is not one of the verbs that is defined in the HTTP specification [RFC2616], using the MERGE verb may not flow through network intermediaries as seamlessly as methods that are defined in the HTTP specification. The HTTP PATCH verb is preferred over HTTP MERGE when working with data services that support the OData 3.0 protocol. Data services that support the OData 2.0 and OData 3.0 protocols can support verb tunneling to mitigate this limitation, as defined in Tunneled Requests (section 2.2.7.7).