IAmazonDynamoDB.UpdateItem Method (UpdateItemRequest)

Edits an existing item's attributes, or inserts a new item if it does not already exist. You can put, delete, or add attribute values. You can also perform a conditional update (insert a new attribute name-value pair if it doesn't exist, or replace an existing name-value pair if it has certain expected attribute values).

In addition to updating an item, you can also return the item's attribute values in the same operation, using the ReturnValues parameter.

Syntax

Examples

This example shows how to update an item in a table.

UpdateItem sample

// Create a client
AmazonDynamoDBClient client = new AmazonDynamoDBClient();

// Define item key
//  Hash-key of the target item is string value "Mark Twain"
//  Range-key of the target item is string value "The Adventures of Tom Sawyer"
Dictionary<string, AttributeValue> key = new Dictionary<string, AttributeValue>
{
    { "Author", new AttributeValue { S = "Mark Twain" } },
    { "Title", new AttributeValue { S = "The Adventures of Tom Sawyer" } }
};

// Define attribute updates
Dictionary<string, AttributeValueUpdate> updates = new Dictionary<string, AttributeValueUpdate>();
// Update item's Setting attribute
updates["Setting"] = new AttributeValueUpdate()
{
    Action = AttributeAction.PUT,
    Value = new AttributeValue { S = "St. Petersburg, Missouri" }
};
// Remove item's Bibliography attribute
updates["Bibliography"] = new AttributeValueUpdate()
{
    Action = AttributeAction.DELETE
};   
// Add a new string to the item's Genres SS attribute
updates["Genres"] = new AttributeValueUpdate()
{
    Action = AttributeAction.ADD,
    Value = new AttributeValue { SS = new List<string> { "Bildungsroman" } }
};

// Create UpdateItem request
UpdateItemRequest request = new UpdateItemRequest
{
    TableName = "SampleTable",
    Key = key,
    AttributeUpdates = updates
};

// Issue request
client.UpdateItem(request);

                

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