The RestPatch operator is not a standard OCL operator. However, RestPatch is a term used in some APIs (Application Programming Interface) and web frameworks to refer to a PATCH request method used to update a resource's partial state.

In other words, RestPatch combines two concepts: REST (Representational State Transfer) and PATCH. REST is an architectural style that provides a standardized approach to building web services. It defines a set of constraints that web services must adhere to, such as the use of HTTP methods and resources. PATCH is an HTTP method used to update a resource's partial state.

RestPatch can be used to update one or more attributes of a resource while leaving the others unchanged. This can be useful when updating a large resource, where updating the entire resource would be inefficient or unnecessary. RestPatch can also be used to implement optimistic concurrency control, where the client sends the original state of the resource along with the update request, and the server checks if the resource has been updated by another client before applying the changes.

Example:

Let's say you have a web application that allows users to update their profile information. Each user's profile is represented by a resource in your application, and the resource has several attributes such as name, email, and phone number.

If a user wants to update their phone number, they could use the RestPatch operator to send a PATCH request to the server with the updated phone number value. The server would then update the user's profile resource with the new phone number value while leaving the other attributes unchanged.

For example, the PATCH request might look something like this:

PATCH /api/users/1234 HTTP/1.1
Host: example.com
Content-Type: application/json
Content-Length: 27

{
    "phoneNumber": "555-1234"
}

In this example, the user is updating their phone number for the profile resource with ID 1234. The RestPatch operator allows the user to update just the phone number attribute, leaving the other attributes (such as name and email) unchanged.