Azure table storage - Simplest possible example

18
votes

Whenever learning new technologies I like to write the simplest possible example. Usually this means a console app with the least number of references. I've been trying, with little success, to write an app that reads and writes to Azure table storage. I've used this how-to guide as a basis, but try to do everything in the Main method. Similar approach worked well with the blob storage, but the table storage is giving trouble.

I was able to create a table with this code.

static void Main(string[] args)
{
    Microsoft.WindowsAzure.Storage.Table.CloudTableClient tableClient =
    new Microsoft.WindowsAzure.Storage.Table.CloudTableClient(
        new Uri("http://mystorage.table.core.windows.net/"),
    new Microsoft.WindowsAzure.Storage.Auth.StorageCredentials("[somename]", "[somekey]"));

    CloudTable table = tableClient.GetTableReference("people");
    table.CreateIfNotExists();
}

After running this code I could see a table in my storage using Azure Storage Explorer. (Still haven't figured out how to see the table in manage.windowsazure.com.)

However, if I try to insert records (as described in the how-to guide mentioned before), I get a conflict 409 EntityAlreadyExists. Azure Storage Explorer doesn't show any records in my table.

CustomerEntity customer1 = new CustomerEntity("Harp", "Walter");
customer1.Email = "[email protected]";
customer1.PhoneNumber = "425-555-0101";

TableOperation insertOperation = TableOperation.Insert(customer1);
table.Execute(insertOperation);

Also, I'm baffled by the two overlapping namespaces. Both Microsoft.WindowsAzure.Storage.Table and Microsoft.WindowsAzure.StorageClient contain e.g. a CloudTableClient class. Why are there two client namespaces and which one am I supposed to use?

EDIT Turns out the record does exist. Simply double-clicking the table in Azure Table Explorer doesn't show the table contents. You have to click Query. The last question still stands. Why the two namespaces?

2
azure-table-storage

2 Answers

22
votes

The simplest sample I could think of is this. You need to NuGet WindowsAzure.Storage 2.0.

static void Main(string[] args)
{
  try
  {
     CloudStorageAccount storageAccount =
        CloudStorageAccount.Parse("DefaultEndpointsProtocol=https;AccountName=<your_storage_name>;AccountKey=<your_account_key>");
     CloudTableClient tableClient = storageAccount.CreateCloudTableClient();

     CloudTable table = tableClient.GetTableReference("people");
     table.CreateIfNotExists();

     CustomerEntity customer1 = new CustomerEntity("Harp", "Walter");
     customer1.Email = "[email protected]";
     customer1.PhoneNumber = "425-555-0101";

     // Create the TableOperation that inserts the customer entity.
     var insertOperation = TableOperation.Insert(customer1);

     // Execute the insert operation.
     table.Execute(insertOperation);

     // Read storage
     TableQuery<CustomerEntity> query =
        new TableQuery<CustomerEntity>()
           .Where(TableQuery.GenerateFilterCondition("PartitionKey",
               QueryComparisons.Equal, "Harp"));
     var list = table.ExecuteQuery(query).ToList();
   }
   catch (StorageException ex)
   {
       // Exception handling here.
   }
}

public class CustomerEntity : TableEntity
{
    public string Email { get; set; }
    public string PhoneNumber { get; set; }

    public CustomerEntity(string lastName, string firstName)
    {
        PartitionKey = lastName;
        RowKey = firstName;
    }

    public CustomerEntity() { }
}

The answer to the seconds question, why are there two namespaces that provided more or less the same APIs, Azure Storage Client Library 2.0 contains a new simplified API. See link below.

What's New in Storage Client Library for .NET (version 2.0)

1
votes

Thanks so much for this! Been searching for ages for a simple example of connecting to Azure Table Storage in your development environment. From your examples above I formulated the code below: 

using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Auth;
using Microsoft.WindowsAzure.Storage.Table;

namespace Bootstrapping
{
  public class Builder
  {

    public void Run()
    {
      CloudStorageAccount storageAccount =
        CloudStorageAccount.Parse("UseDevelopmentStorage=true");
      CloudTableClient tableClient = storageAccount.CreateCloudTableClient();

      CloudTable table = tableClient.GetTableReference("people");
      table.CreateIfNotExists();

    }

  }
}