Recently one of my friend was unable to update display name of an item. It was working fine for other items though. We checked item:saving event handler but could not find anything which could have caused this issue. Then i found this stackoverflow link and tried checking directly in database
http://stackoverflow.com/questions/29850067/unable-to-change-display-name-of-item-why
I ran below sql query where fieldid is of "__Display Name" field and itemid is the item which was giving trouble.
SELECT *
FROM [dbo].[UnversionedFields]
WHERE ItemId = '{39F976FA-0ADC-4CE3-B600-449D33FE30FA}'
AND FieldId = '{B5E02AD9-D56F-4C41-A065-A133DB87BDEB}'
It gave me two results ,
everytime i was updating my display name it was updating the row which is having "en" language in column. but content tree was always showing the value from the row which has language value as blank.
i checked if i have anyother blank language values . but could not find anything.
SELECT *
FROM [dbo].[UnversionedFields]
WHERE Language=''
SELECT *
FROM [dbo].[VersionedFields]
WHERE Language=''
we deleted the item and reinstalled that item package from another server and it started working working fine.
if you have lot of items you can try running below sql query after taking your database backup. It should fix the issue
delete
FROM [dbo].[UnversionedFields]
WHERE Language=''
