无法更新EntitySet

以下代码:

sistema_log_openedPdfs entity = new sistema_log_openedPdfs();
entity.idUser = guid;
entity.path = fullAbsPath;
context.sistema_log_openedPdfs.Add(entity);
context.SaveChanges();

我得到了这个疯狂的异常:

[UpdateException: Unable to update the EntitySet 'sistema_log_openedPdfsbecause it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation.]

寻找帮助我找不到任何帮助