diff --git a/dictdatabase/dataclasses.py b/dictdatabase/dataclasses.py
new file mode 100644
index 0000000..2c54e19
--- /dev/null
+++ b/dictdatabase/dataclasses.py
@@ -0,0 +1,8 @@
+import dataclasses
+
+
+@dataclasses.dataclass(frozen=True)
+class SearchResult:
+    start_byte: int
+    end_byte: int
+    found: bool
diff --git a/dictdatabase/io_unsafe.py b/dictdatabase/io_unsafe.py
index fbc405b..7c8cba2 100644
--- a/dictdatabase/io_unsafe.py
+++ b/dictdatabase/io_unsafe.py
@@ -185,16 +185,16 @@ def get_partial_file_handle(db_name: str, key: str) -> PartialFileHandle:
 		return partial_handle
 
 	# Not found in index file, search for key in the entire file
-	key_start, key_end, found = searching.search_key_position_in_db(all_file_bytes, key)
+	position = searching.search_key_position_in_db(all_file_bytes, key)
 
-	if not found:
+	if not position.found:
 		raise KeyError(f"Key \"{key}\" not found in db \"{db_name}\"")
 
 	# Key found, now determine the bounding byte indices of the value
-	start = key_end + (1 if all_file_bytes[key_end] == byte_codes.SPACE else 0)
+	start = position.end_byte + (1 if all_file_bytes[position.end_byte] == byte_codes.SPACE else 0)
 	end = utils.seek_index_through_value_bytes(all_file_bytes, start)
 
-	indent_level, indent_with  = utils.detect_indentation_in_json_bytes(all_file_bytes, key_start)
+	indent_level, indent_with = utils.detect_indentation_in_json_bytes(all_file_bytes, position.start_byte)
 
 	partial_value = orjson.loads(all_file_bytes[start:end])
 	prefix_bytes = all_file_bytes[:start] if config.use_compression else None
diff --git a/dictdatabase/searching.py b/dictdatabase/searching.py
index 62ed857..697819b 100644
--- a/dictdatabase/searching.py
+++ b/dictdatabase/searching.py
@@ -4,9 +4,10 @@
 
 from dictdatabase import byte_codes
 from dictdatabase import utils
+from dictdatabase.dataclasses import SearchResult
 
 
-def find_key_position_in_bytes(file: bytes, key: str) -> Tuple[int, int, bool]:
+def find_key_position_in_bytes(file: bytes, key: str) -> SearchResult:
     """
     It finds the start and end indices of the value of a key in a JSON file
 
@@ -19,13 +20,15 @@ def find_key_position_in_bytes(file: bytes, key: str) -> Tuple[int, int, bool]:
     """
     key_start, key_end = utils.find_outermost_key_in_json_bytes(file, key)
     if key_end == -1:
-        return -1, -1, False
+        return SearchResult(start_byte=-1, end_byte=-1, found=False)
     start = key_end + (1 if file[key_end] == byte_codes.SPACE else 0)
     end = utils.seek_index_through_value_bytes(file, start)
-    return start, end, True
+    return SearchResult(start_byte=start, end_byte=end, found=True)
 
 
-def search_key_position_in_db(file: bytes, key: str, glom_searching=True) -> Tuple[int, int, bool]:
+def search_key_position_in_db(
+    file: bytes, key: str, glom_searching=True
+) -> SearchResult:
     original_value_start = 0
     original_value_end = len(file)
     original_key_start = 0
@@ -33,14 +36,14 @@ def search_key_position_in_db(file: bytes, key: str, glom_searching=True) -> Tup
     for k in key.split(".") if glom_searching else [key]:
         key_start, key_end = utils.find_outermost_key_in_json_bytes(file, k)
         if key_end == -1:
-            return -1, -1, False
+            return SearchResult(start_byte=-1, end_byte=-1, found=False)
         original_key_end = original_value_start + key_end
         original_key_start = original_value_start + key_start
-        value_start, value_end, found = find_key_position_in_bytes(file, k)
+        position = find_key_position_in_bytes(file, k)
         original_value_end = original_value_start + original_value_end
-        original_value_start += value_start
+        original_value_start += position.start_byte
         file = file[original_value_start:original_value_end]
-    return original_key_start, original_key_end, True
+    return SearchResult(start_byte=original_key_start, end_byte=original_key_end, found=True)
 
 
 def search_value_position_in_db(
@@ -61,11 +64,11 @@ def search_value_position_in_db(
     original_start = 0
     original_end = len(all_file_bytes)
     for k in key.split(".") if glom_searching else [key]:
-        start, end, found = find_key_position_in_bytes(
+        position = find_key_position_in_bytes(
             all_file_bytes[original_start:original_end], k
         )
-        if not found:
+        if not position.found:
             return -1, -1, False
-        original_end = original_start + end
-        original_start += start
+        original_end = original_start + position.end_byte
+        original_start += position.start_byte
     return original_start, original_end, True
diff --git a/tests/test_glom_writing.py b/tests/test_glom_writing.py
index 2702884..4255cd0 100644
--- a/tests/test_glom_writing.py
+++ b/tests/test_glom_writing.py
@@ -1,3 +1,5 @@
+import pytest
+
 import dictdatabase as DDB
 
 data = {
@@ -15,3 +17,11 @@ def test_glom_writing():
         purchase["status"] = "cancelled"
         session.write()
     assert DDB.at("users", key="users.Ben.status").read() == "cancelled"
+
+
+def test_glom_writing_sub_key_not_exists():
+    DDB.at("users").create(data, force_overwrite=True)
+    with pytest.raises(KeyError):
+        with DDB.at("users", key="users.SUBKEY").session() as (session, purchase):
+            purchase["status"] = "cancelled"
+            session.write()