Azure Table Storage InsertOrMerge

Question

I have an Azure Table Storage that contains some data. I need to update one single property for all records in the table. I know the partition key and rowkey for each item. However might be so that I have new items in my CSV file.

What I need to do is:

• if an item is found in the table storage based on ParitionKey and RowKey I want to update one single property: Name.
• if an item is not found in the table it must be inserted but I have more properties that need to be filled: Name, Email, Address

I am trying to use InsertOrMerge but I got an Etag exception and how can I set up more properties if the item is not found and an insert will be required?

var storageAccount = CloudStorageAccount.Parse(connectionString);
var cloudTableClient = storageAccount.CreateCloudTableClient();
var ct = cloudTableClient.GetTableReference("mytable");

var item = new Item()
{
    PartitionKey = "PARTITIONID",
    RowKey = "ROWID",                
    Name = "DEMO",                     
};

var to = TableOperation.Merge(code);
var result = await ct.ExecuteAsync(to);

Answer 1

I also got etag exception when I use Merge to operate a entity not exist in table.

System.ArgumentException: 'Merge requires an ETag (which may be the '*' wildcard).'

Your requirement can be achieved by Retrieve and InsertOrMerge.

Add two properties Email and Address to your Item class.

 public class Item: TableEntity
 {
    public Item(String PartitionKey, String RowKey, String Name, String Email=null, String Address=null)
    {
        this.RowKey = RowKey ;
        this.PartitionKey = PartitionKey;
        this.Name = Name;
        this.Email = Email;
        this.Address = Address;
    }

    public Item(){}

    public String Name { get; set; }

    public String Email { get; set; }

    public String Address { get; set; }

}

Add if switch to tell which properties are to load.

 TableOperation to = TableOperation.Retrieve<Item>("PK","RK");

 TableResult tr = table.ExecuteAync(to).Result;

 var item;

 if (tr != null)
 {
     item = new Item
     {
         PartitionKey = "PARTITIONID",
         RowKey = "ROWID",                
         Name = "DEMO",  
     }
 }
 else
 {
     item = new Item
     {
         PartitionKey = "PARTITIONID",
         RowKey = "ROWID",                
         Name = "DEMO",  
         Email = "test@example.com",
         Address = "Britain"
     }
 }

 to = TableOperation.InsertOrMerge(item);

 tr = await ct.ExecuteAysnc(to).Result;

. When you execute InsertOrMerge,

• If the item exists, its content(Name) will be updated by your new item.
• If it doesn't exist, it will be inserted as expected.