The Open Data Protocol (OData) includes standard CRUD (Create, Retrieve, Update, and Delete) operations that map to the HTTP methods POST, GET, PUT/MERGE, and DELETE.
In addition, OData supports further service operations (function imports) that can be invoked by the HTTP methods GET or POST for anything that cannot be mapped to the standard CRUD operations. You can implement such additional service operations in the Service Builder by creating function imports within your data model.
For example, you could create function imports for the following custom operations:
Confirm Work Item
Check Flight Availability
While it is simple to create new function imports to invoke custom operations, if the operation you want to use can be invoked using a standard CRUD operation, you should not create a function import. That is, you should only create function imports for custom operations that cannot be invoked using a standard operation.
To create a function import for a custom operation, proceed as follows:
Right click the Data Model folder, and select Create . The Create Function Import dialog box opens.
In Return Type Kind column select the kind of return type (if any) you want the function import to return data at runtime.
In the Return Type column, enter the name of the complex type or entity type you want the function import to return. You can use the input help to select an existing complex type or entity type from your project. If the input help is empty, you must first create the relevant complex type or entity type in your project. If you selected No Return this field is disabled.
In the Return Cardinality select the cardinality using input help.
If return type of function import is an Entity Type and:
If the key properties of entity type are of Core Type Edm.DateTime, Edm.DateTimeoffset or Edm.Guid, Return Cardinality 0..1 is not allowed because, for these Core Types initial ABAP value is not a valid edm value and it can cause runtime exception. If you select 0..1, an error message is displayed.
If the key properties of entity type is other than Edm.DateTime, or Edm.DateTimeoffset, or Edm.Guid, and Return Cardinality 0..1 is selected, a warning message is displayed as cardinality 0..1 is not recommended for any Core Type as per OData standards.
While upgrading if your project contains Function Import and it's return type is an entity type having key fields of core type Edm.DateTime, Edm.DateTimeoffset or Edm.Guid, you get an error message.
If you have set the Return Cardinality 0..1 or 1..n , you must enter the entity set that has to be used in the Return Entity Set column. In other cases, this column is disabled.
Select the HTTP method to invoke the function import. If you do not select an HTTP method, you have to invoke the function import using the GET or POST method.
In Action for Entity Type column select the entity type to which the function import applies semantically as an action. While this setting has no effect at runtime, it can help you to determine which function import belong to a particular entity type.
In the Label column, you can enter a label for the new function import. You can enter a free-text label directly or use the Label Text Reference Editor to enter the reference type (program, data element, or class). The reference type you select influences the other input fields (Object Name, Key, and Label) you have to edit.
Specify the Function Import name. Function Imports opens in mass maintenance view. Do the following in mass maintenance view:
You can create a subsequent function import when you right click Function Import folder and select Create and follow above procedure.
Alternatively, In the mass maintenance view of Function Imports, click Display/Changeand then Insert Rowto add new Function Import.
To delete a function import select the relevant function import row from the mass maintenance view and click Delete Row.
Click Save to save the changes and invoke the custom operation at runtime.