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# JSON support in Amazon DynamoDB
<a name="dynamodb-json"></a>

**Note**  
The information in this topic is specific to projects based on .NET Framework and the AWS SDK for .NET version 3.3 and earlier.

The AWS SDK for .NET supports JSON data when working with Amazon DynamoDB. This enables you to more easily get JSON-formatted data from, and insert JSON documents into, DynamoDB tables.

**Topics**
+ [Get Data from a DynamoDB Table in JSON Format](#dynamodb-json-get-table-data)
+ [Insert JSON Format Data into a DynamoDB Table](#dynamodb-json-insert-table-data)
+ [DynamoDB Data Type Conversions to JSON](#dynamodb-json-datatypes)
+ [More Info](#dynamodb-json-more-info)

## Get Data from a DynamoDB Table in JSON Format
<a name="dynamodb-json-get-table-data"></a>

The following example shows how to get data from a DynamoDB table in JSON format:

```
// using Amazon.DynamoDBv2;
// using Amazon.DynamoDBv2.DocumentModel;

var client = new AmazonDynamoDBClient();
var table = Table.LoadTable(client, "AnimalsInventory");
var item = table.GetItem(3, "Horse");

var jsonText = item.ToJson();
Console.Write(jsonText);
      
// Output:
//   {"Name":"Shadow","Type":"Horse","Id":3}

var jsonPrettyText = item.ToJsonPretty();
Console.WriteLine(jsonPrettyText);
      
// Output:
//   {
//     "Name" : "Shadow",
//     "Type" : "Horse",
//     "Id"   : 3
//   }
```

In the preceding example, the `ToJson` method of the `Document` class converts an item from the table into a JSON-formatted string. The item is retrieved through the `GetItem` method of the `Table` class. To determine the item to get, in this example, the `GetItem` method uses the hash-and-range primary key of the target item. To determine the table to get the item from, the `LoadTable` method of the `Table` class uses an instance of the `AmazonDynamoDBClient` class and the name of the target table in DynamoDB.

## Insert JSON Format Data into a DynamoDB Table
<a name="dynamodb-json-insert-table-data"></a>

The following example shows how to use JSON format to insert an item into a DynamoDB table:

```
// using Amazon.DynamoDBv2;
// using Amazon.DynamoDBv2.DocumentModel;

var client = new AmazonDynamoDBClient();
var table = Table.LoadTable(client, "AnimalsInventory");
var jsonText = "{\"Id\":6,\"Type\":\"Bird\",\"Name\":\"Tweety\"}";
var item = Document.FromJson(jsonText);

table.PutItem(item);
```

In the preceding example, the `FromJson` method of the `Document` class converts a JSON-formatted string into an item. The item is inserted into the table through the `PutItem` method of the `Table` class, which uses the instance of the `Document` class that contains the item. To determine the table to insert the item into, the `LoadTable` method of the `Table` class is called, specifying an instance of the `AmazonDynamoDBClient` class and the name of the target table in DynamoDB.

## DynamoDB Data Type Conversions to JSON
<a name="dynamodb-json-datatypes"></a>

Whenever you call the `ToJson` method of the `Document` class, and then on the resulting JSON data you call the `FromJson` method to convert the JSON data back into an instance of a `Document` class, some DynamoDB data types will not be converted as expected. Specifically:
+ DynamoDB sets (the `SS`, `NS`, and `BS` types) will be converted to JSON arrays.
+ DynamoDB binary scalars and sets (the `B` and `BS` types) will be converted to base64-encoded JSON strings or lists of strings.

  In this scenario, you must call the `DecodeBase64Attributes` method of the `Document` class to replace the base64-encoded JSON data with the correct binary representation. The following example replaces a base64-encoded binary scalar item attribute in an instance of a `Document` class, named `Picture`, with the correct binary representation. This example also does the same for a base64-encoded binary set item attribute in the same instance of the `Document` class, named `RelatedPictures`:

  ```
  item.DecodeBase64Attributes("Picture", "RelatedPictures");
  ```

## More Info
<a name="dynamodb-json-more-info"></a>

For more information and examples of programming JSON with DynamoDB with the AWS SDK for .NET, see:
+  [DynamoDB JSON Support](https://aws.amazon.com/blogs/developer/dynamodb-json-support/) 
+  [Amazon DynamoDB Update - JSON, Expanded Free Tier, Flexible Scaling, Larger Items](https://aws.amazon.com/blogs/aws/dynamodb-update-json-and-more/)