Error Resolution For EF6 in C#

I am having C# project where i am using EF6 with MySQL, everything is working fine but at one place where i have one to one mapping i am getting below error, its just 30 min task so bid accordingly :- An error occurred while saving entities that do not expose foreign key properties for their relationships. The EntityEntries property will return null because a single entity cannot be identified as the source of the exception. Handling of exceptions while saving can be made easier by exposing foreign key properties in your entity types. See the InnerException for details. Store update, insert, or delete statement affected an unexpected number of rows (0). Entities may have been modified or deleted since entities were loaded. See [login to view URL] for information on understanding and handling optimistic concurrency exceptions.