A granite-stair repair photo blob already has metadata crew=a. A later Set Metadata call sends only shift=night, and crew disappears. What should the developer understand?
Select an answer to reveal the explanation.
Short Explanation
Sending a new metadata bag swaps the whole locker—it does not quietly merge. Get the current metadata, merge in shift=night, then set the combined dictionary. That is why crew vanished.
Full Explanation
Azure Blob Set Metadata replaces the complete user metadata collection on the blob with the values supplied in the call. Developers who need to add or update one key must retrieve existing metadata, merge changes in the application, and then set the full dictionary. Metadata is neither append-only nor cleared only by Content-Type updates.