I'm not getting that DB problem with the long string, but yes the length must be checked and trimmed to an acceptable value.
Regarding the CommitChanges fail situation. The fail can be related to many things, like file in use, unhandled situation exception (unknown error), etc. A status code is preferable, and may be provided in a future implementation, but knowing that it failed is sufficient to be aware that a file in particular needs to be checked.