Merge pull request #7153 from gmndrg/main

Update with JSON update field behavior of null

Author: prmerger-automator[bot]

articles/search/search-howto-index-json-blobs.md

@@ -9,7 +9,7 @@ ms.service: azure-ai-search
 ms.custom:
   - ignite-2023
 ms.topic: how-to
-ms.date: 07/25/2025
+ms.date: 09/18/2025
 ms.update-cycle: 365-days
 ---
 
@@ -75,6 +75,7 @@ api-key: [admin key]
 
 > [!NOTE]
 > As with all indexers, if fields don't clearly match, you should expect to explicitly specify individual [field mappings](search-indexer-field-mappings.md) unless you're using the implicit fields mappings available for blob content and metadata, as described in [basic blob indexer configuration](search-howto-indexing-azure-blob-storage.md).
+> To override an existing index value, the source JSON must provide a non-null value. If the field in the source document is null, the indexer will retain the existing value. To explicitly clear a field, pass an empty string ("") instead. This prevents unintended deletions from the index.
 
 ### json example (single hotel JSON files)