Home > Uncategorized > Getting started with #DynamoDB in C#

Getting started with #DynamoDB in C#

DynamoDB is a good way to get started with NoSQL databases, and being hosted in AWS, means that you don’t have to worry about servers or backups.

Now, a few assumptions before starting. I’m assuming that you’ve set up a test table, with at least item, with primary key called id of type string. I’m also assuming your development machine has stored AWS credentials, (AWS configure), since they won’t be in the code.

So, step 1, we’ll install two NUGET packages;

Install-Package AWSSDK.DynamoDBv2 
Install-Package Newtonsoft.Json


Then, we'll set up a private static reference to our client as follows;
private static readonly AmazonDynamoDBClient Client = new AmazonDynamoDBClient();

The code supplied on Amazon for listing tables is designed to list any number of tables, however, this simplified version will read up to 100 tables. But here is a simplified version;

private static void ListMyTables()
{
 var response = Client.ListTablesAsync().Result;
 response.TableNames.ForEach(Console.WriteLine);
}

Now, Imagine we want to read an item from the table, by id and return the data as JSON, we’d use;

private static string GetJsonById(string tableName, string id)
{
	var request = new QueryRequest
	{
		TableName = tableName,
		KeyConditionExpression = "id = :v_Id",
		ExpressionAttributeValues = new Dictionary<string, AttributeValue> {
			{":v_Id", new AttributeValue { S =  id }}}
	};

	var response = Client.QueryAsync(request).Result;

	return JsonConvert.SerializeObject(response.Items, Formatting.Indented);
}

Where we pass the table name, and the id, and it returns as JSON.

And finally, let’s imagine we want to write to the table, with some JSON;

private static void CreateItemFromJson(string tableName, string jsonText)
{	
	var item = Document.FromJson(jsonText);
	var table = Table.LoadTable(Client, tableName);
	var ignore =table.PutItemAsync(item).Result;
}

And that’s the basic read/write functionality of DynamoDB.

Categories: Uncategorized
  1. No comments yet.
  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: