feat: implement delete() in JsonDBItem for sdb:select-item support

bundles/sirix-query/src/main/java/io/sirix/query/json/JsonDBItem.java

@@ -21,14 +21,21 @@ public interface JsonDBItem extends UpdatableJsonItem {
    */
   @Override
   default void replaceValue(Sequence newValue) {
-    final JsonNodeReadOnlyTrx rtx = getTrx();
-    rtx.moveTo(getNodeKey());
-
     final JsonResourceSession resourceSession = getResourceSession();
     final JsonNodeTrx wtx = resourceSession.getNodeTrx().orElseGet(resourceSession::beginNodeTrx);
     wtx.moveTo(getNodeKey());
-
-    // Use the JsonItemSequence utility to perform the replacement
     JsonItemSequence.replaceValue(wtx, newValue, getCollection());
   }
+
+  /**
+   * Default implementation of delete that removes this item from its parent.
+   * This enables the use of sdb:select-item with delete expressions.
+   */
+  @Override
+  default void delete() {
+    final JsonResourceSession resourceSession = getResourceSession();
+    final JsonNodeTrx wtx = resourceSession.getNodeTrx().orElseGet(resourceSession::beginNodeTrx);
+    wtx.moveTo(getNodeKey());
+    wtx.remove();
+  }
 }

bundles/sirix-query/src/test/java/io/sirix/query/JsonIntegrationTest.java

@@ -713,6 +713,39 @@ public void testRemoveFromObject() throws IOException {
     test(storeQuery, updateQuery, openQuery, "{\"baz\":true}");
   }
 
+  @Test
+  public void testRemoveFromObjectViaSdbSelectItem() throws IOException {
+    final String storeQuery = """
+          jn:store('json-path1','mydoc.jn','{"foo": "bar", "baz": true}')
+        """;
+    // Use sdb:select-item to get the 'foo' object-record (nodeKey 2) and delete it directly
+    final String updateQuery = """
+          delete json sdb:select-item(jn:doc('json-path1','mydoc.jn'), 2)
+        """;
+    final String openQuery = "jn:doc('json-path1','mydoc.jn')";
+    test(storeQuery, updateQuery, openQuery, "{\"baz\":true}");
+  }
+
+  @Test
+  public void testUpdateThenDeleteSameNode() throws IOException {
+    // Per XQuery Update Facility 1.0 section 3.2.1:
+    // "If a node is marked for deletion, updates to its properties have no effect."
+    // Brackit should skip the update and only apply the delete.
+    // 
+    // In this test, we use sdb:select-item for both update and delete to target
+    // the exact same item (the "name" object record at nodeKey 2).
+    final String storeQuery = """
+          jn:store('json-path1','mydoc.jn','{"name": "original", "other": 123}')
+        """;
+    // Update and delete the same node (nodeKey 2 = "name" object record) - update should be skipped
+    final String updateQuery = """
+          let $item := sdb:select-item(jn:doc('json-path1','mydoc.jn'), 2)
+          return (replace json value of $item with "updated", delete json $item)
+        """;
+    final String openQuery = "jn:doc('json-path1','mydoc.jn')";
+    test(storeQuery, updateQuery, openQuery, "{\"other\":123}");
+  }
+
   @Test
   public void testRenameFieldInObject() throws IOException {
     final String storeQuery = """