Azure Storage Tables

A NoSQL key-value store for massive scalability and flexible schemas.

Introduction to Azure Storage Tables

Azure Storage Tables offer a schemaless NoSQL key-value store for storing large amounts of structured, non-relational data. They are part of Azure Storage and are highly scalable, cost-effective, and designed for applications that require high throughput and low latency access to data.

Unlike traditional relational databases, tables do not enforce a schema. Each entity (row) can have a different set of properties. This flexibility makes them ideal for a wide range of scenarios, including:

Key Concepts

Entities

An entity is a record within a table, similar to a row in a relational database. Each entity can contain up to 100 properties, with a total size limit of 1MB.

Properties

Properties are name-value pairs that make up an entity. Property names are strings (up to 255 characters), and values can be of various data types, including strings, integers, booleans, dates, GUIDs, and binary data.

PartitionKey and RowKey

Every entity in a table must have a PartitionKey and a RowKey. These two properties form the primary key for the entity and uniquely identify it within a table.

  • PartitionKey: Groups entities together. Entities with the same PartitionKey are stored in the same partition, which improves query performance for data within a partition.
  • RowKey: Uniquely identifies an entity within a partition.

Choosing appropriate PartitionKey and RowKey values is crucial for performance and scalability. Often, a combination of tenant ID, date, or user ID is used for PartitionKey, and a unique identifier for RowKey.

Tables

A table is a collection of entities. Tables are schemaless, meaning entities within the same table do not need to have the same set of properties.

Getting Started

To use Azure Storage Tables, you first need an Azure Storage Account. You can create one via the Azure portal, Azure CLI, or Azure PowerShell.

Once you have a storage account, you can interact with tables using the Azure Storage SDKs or the Azure REST API.

Creating a Table

You can create a table programmatically using the Azure SDKs. Here's a conceptual example using C# (the syntax may vary slightly between SDKs):


// Initialize storage account and table client
CloudStorageAccount storageAccount = CloudStorageAccount.Parse("YOUR_AZURE_STORAGE_CONNECTION_STRING");
CloudTableClient tableClient = storageAccount.CreateCloudTableClient();
CloudTable table = tableClient.GetTableReference("mySampleTable");

// Create the table if it doesn't exist
table.CreateIfNotExists();

Azure Storage SDKs

Azure provides SDKs for various programming languages, making it easy to integrate Azure Storage Tables into your applications:

These SDKs abstract away the complexities of the REST API, providing a more intuitive and efficient way to perform operations such as:

Common Operations and Examples

Inserting an Entity

Inserting an entity involves creating an entity object and then calling an insert operation.


// Assume 'table' is an initialized CloudTable object
MyEntity entity = new MyEntity("partition1", "row1");
entity.MyProperty = "Hello, Azure Tables!";
entity.Timestamp = DateTimeOffset.UtcNow;

TableOperation insertOperation = TableOperation.Insert(entity);
table.Execute(insertOperation);

Querying Entities

Queries can be targeted or broad. Filtering by PartitionKey and RowKey is the most efficient.


// Retrieve a single entity by partition and row key
TableOperation retrieveOperation = TableOperation.Retrieve("partition1", "row1");
TableResult retrievedResult = table.Execute(retrieveOperation);
MyEntity retrievedEntity = (MyEntity)retrievedResult.Result;

// Query entities within a partition
string filter = TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, "partition1");
TableQuery query = new TableQuery().Where(filter);

foreach (MyEntity entity in table.ExecuteQuery(query))
{
    Console.WriteLine($"Found entity: {entity.RowKey}, {entity.MyProperty}");
}

Updating an Entity

You can update an existing entity using TableOperation.Replace or TableOperation.Merge.


// Assume 'retrievedEntity' is an existing entity
retrievedEntity.MyProperty = "Updated value!";

TableOperation updateOperation = TableOperation.Replace(retrievedEntity);
table.Execute(updateOperation);

Deleting an Entity

Deleting an entity requires you to know its PartitionKey and RowKey.


// Assume 'retrievedEntity' is the entity to delete
TableOperation deleteOperation = TableOperation.Delete(retrievedEntity);
table.Execute(deleteOperation);

Best Practices