**To add an item to a table** This example adds a new item to the *MusicCollection* table. Command:: aws dynamodb put-item --table-name MusicCollection --item file://item.json --return-consumed-capacity TOTAL The arguments for ``--item`` are stored in a JSON file, ``item.json``. Here are the contents of that file:: { "Artist": {"S": "No One You Know"}, "SongTitle": {"S": "Call Me Today"}, "AlbumTitle": {"S": "Somewhat Famous"} } Output:: { "ConsumedCapacity": { "CapacityUnits": 1.0, "TableName": "MusicCollection" } } **Conditional Expressions** This example shows how to perform a one-line conditional expression operation. This put-item call to the table *MusicCollection* table will only succeed if the artist "Obscure Indie Band" does not exist in the table. Command:: aws dynamodb put-item --table-name MusicCollection --item '{"Artist": {"S": "Obscure Indie Band"}}' --condition-expression "attribute_not_exists(Artist)" If the key already exists, you should see: Output:: A client error (ConditionalCheckFailedException) occurred when calling the PutItem operation: The conditional request failed