title: Append more data to serialized json blobs
body: <p>I'm trying to query employee data from a rest endpoint periodically and save it to my SQL Server DB using an ADF copy activity. All employee data that is queried on the day is added to an azure blob with the filename corresponding to that day. In my Azure function, I serialize my object using <code>JsonConvert.SerializeObject(employee)</code> and store it as <strong>fileName_currentDate.txt</strong> after which the data looks something like this:</p>
  
  <pre><code>[
   {
    name: "abc",
    address: "pqr"
   },
   {
    name:"efg",
    address: "efg"
   }
  ]
  </code></pre>
  
  <p><strong>Problem</strong>: I want to keep appending more employees to the file with the matching date part. </p>
  
  <p><strong>Constraint</strong>: I don't want to download the existing blob to the server using something like <code>blob.DownloadToStream(stream)</code>, de-serialize it ,add the extra data to my object, and then save it back to the blob container. This will be an expensive operation when the number of times I need to append is large and also when the blob size doesn't fit into memory.</p>
  
  <p>What are my options here?</p>
  
  <p>I see that there's support for <strong>Append Blob Storage</strong> which is what I plan to use in my app, however I cannot understand how I'd add more data to my json blob.</p>