**To update an item in a table** This example updates an item in the *MusicCollection* table. It adds a new attribute (*Year*) and modifies the *AlbumTitle* attribute. All of the attributes in the item, as they appear after the update, are returned in the response. Command:: aws dynamodb update-item --table-name MusicCollection --key file://key.json --update-expression "SET #Y = :y, #AT = :t" --expression-attribute-names file://expression-attribute-names.json --expression-attribute-values file://expression-attribute-values.json --return-values ALL_NEW The arguments for ``--key`` are stored in a JSON file, ``key.json``. Here are the contents of that file:: { "Artist": {"S": "Acme Band"}, "SongTitle": {"S": "Happy Day"} } The arguments for ``--expression-attribute-names`` are stored in a JSON file, ``expression-attribute-names.json``. Here are the contents of that file:: { "#Y":"Year", "#AT":"AlbumTitle" } The arguments for ``--expression-attribute-values`` are stored in a JSON file, ``expression-attribute-values.json``. Here are the contents of that file:: { ":y":{"N": "2015"}, ":t":{"S": "Louder Than Ever"} } Output:: { "Item": { "AlbumTitle": { "S": "Songs About Life" }, "SongTitle": { "S": "Happy Day" }, "Artist": { "S": "Acme Band" } } }