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Add or replace entity in Azure Table Storage

Asked 2010-12-17T00:40:47.057
17

I'm working with Windows Azure Table Storage and have a simple requirement: add a new row, overwriting any existing row with that PartitionKey/RowKey. However, saving the changes always throws an exception, even if I pass in the ReplaceOnUpdate option:

tableServiceContext.AddObject(TableName, entity);
tableServiceContext.SaveChangesWithRetries(SaveChangesOptions.ReplaceOnUpdate);

If the entity already exists it throws:

System.Data.Services.Client.DataServiceRequestException: An error occurred while processing this request. ---> System.Data.Services.Client.DataServiceClientException: <?xml version="1.0" encoding="utf-8" standalone="yes"?>
<error xmlns="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
  <code>EntityAlreadyExists</code>
  <message xml:lang="en-AU">The specified entity already exists.</message>
</error>

Do I really have to manually query for the existing row first and call DeleteObject on it? That seems very slow. Surely there is a better way?

azure upsert azure-table-storage
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1 Answer

1

Insert/Merge or Update was added to the API in September 2011. Here is an example using the Storage API 2.0 which is easier to understand then the way it is done in the 1.7 api and earlier.

public void InsertOrReplace(ITableEntity entity)
    {
        retryPolicy.ExecuteAction(
            () =>
            {
                try
                {
                    TableOperation operation = TableOperation.InsertOrReplace(entity);
                    cloudTable.Execute(operation);
                }
                catch (StorageException e)
                {
                    string message = "InsertOrReplace entity failed.";

                    if (e.RequestInformation.HttpStatusCode == 404)
                    {
                        message += " Make sure the table is created.";
                    }

                    // do something with message
                }
            });
    }
answered 2013-03-29T18:31:16.030

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