IFS is built to detect if entity has been updated between the time the Flow app has retrieved the data until it's being updated, change tracking. In pre-cloud IFS, developers returned objversion and objid values in modify PL/SQL calls for this purpose.
In OData calls same check can be enforced using entity specific ETag in request headers if-match attribute upon Update operation. ETag value of an entity can only be retrieved by using "Get by key" -operation prior Update operation.
ETag location in response in Get by key -operation
The ETag value returned by IFS is a base64 encoded value of the combination of objid:objversion.
In case you encounter ODP_MISSING_PRECONDITION -error In Update operations, provide the if-match header attribute. By providing the ETag as if-match attribute value; IFS will check that entity has not been updated between your clients "Get by key" request and Update operation.
Using ETag in if-match header attribute
Providing if-match attribute with value *, IFS will dismiss the optimistic concurrency control.
