fix: auto-lowercase table names in _build_lookup_field_models, remove .lower() from example

Agent-Logs-Url: https://github.com/microsoft/PowerPlatform-DataverseClient-Python/sessions/508cd2e9-7649-42ec-b5c4-2768fea34725

Co-authored-by: saurabhrb <32964911+saurabhrb@users.noreply.github.com>

Author: Copilot

examples/advanced/sql_examples.py

@@ -175,9 +175,9 @@ def _run_examples(client):
     try:
         backoff(
             lambda: client.tables.create_lookup_field(
-                referencing_table=child_table.lower(),
+                referencing_table=child_table,
                 lookup_field_name="new_TeamId",
-                referenced_table=parent_table.lower(),
+                referenced_table=parent_table,
                 display_name="Team",
             )
         )

src/PowerPlatform/Dataverse/data/_odata.py

@@ -2358,7 +2358,17 @@ def _build_lookup_field_models(
         Returns ``(LookupAttributeMetadata, OneToManyRelationshipMetadata)``.
         Used by both the batch resolver and ``TableOperations.create_lookup_field``
         to avoid duplicating the metadata assembly logic.
+
+        Note: ``referencing_table`` and ``referenced_table`` are lowercased
+        automatically because Dataverse stores entity logical names in
+        lowercase.  ``lookup_field_name`` is kept as-is (it is a SchemaName).
         """
+        # Dataverse logical names are always lowercase.  Callers may pass
+        # SchemaName-cased values (e.g. "new_SQLTeam"); normalise here so
+        # the relationship metadata uses valid logical names.
+        referencing_lower = referencing_table.lower()
+        referenced_lower = referenced_table.lower()
+
         lookup = LookupAttributeMetadata(
             schema_name=lookup_field_name,
             display_name=Label(
@@ -2375,12 +2385,12 @@ def _build_lookup_field_models(
             lookup.description = Label(
                 localized_labels=[LocalizedLabel(label=description, language_code=language_code)]
             )
-        rel_name = f"{referenced_table}_{referencing_table}_{lookup_field_name}"
+        rel_name = f"{referenced_lower}_{referencing_lower}_{lookup_field_name}"
         relationship = OneToManyRelationshipMetadata(
             schema_name=rel_name,
-            referenced_entity=referenced_table,
-            referencing_entity=referencing_table,
-            referenced_attribute=f"{referenced_table}id",
+            referenced_entity=referenced_lower,
+            referencing_entity=referencing_lower,
+            referenced_attribute=f"{referenced_lower}id",
             cascade_configuration=CascadeConfiguration(delete=cascade_delete),
         )
         return lookup, relationship

tests/unit/test_client.py

@@ -333,6 +333,34 @@ def test_referenced_attribute_auto_generated(self):
 
         self.assertEqual(relationship.referenced_attribute, "accountid")
 
+    def test_mixed_case_table_names_lowered(self):
+        """Test that mixed-case table names are auto-lowered to logical names.
+
+        Only table names (entity logical names) are lowered.
+        lookup_field_name is a SchemaName and keeps its original casing.
+        """
+        self.client.tables.create_lookup_field(
+            referencing_table="new_SQLTask",
+            lookup_field_name="new_TeamId",
+            referenced_table="new_SQLTeam",
+        )
+
+        call_args = self.client.tables.create_one_to_many_relationship.call_args
+        lookup = call_args[0][0]
+        relationship = call_args[0][1]
+
+        # Entity names must be lowercased (Dataverse logical names)
+        self.assertEqual(relationship.referenced_entity, "new_sqlteam")
+        self.assertEqual(relationship.referencing_entity, "new_sqltask")
+        self.assertEqual(relationship.referenced_attribute, "new_sqlteamid")
+
+        # Schema_name: table names lowered, lookup_field_name keeps casing
+        self.assertEqual(relationship.schema_name, "new_sqlteam_new_sqltask_new_TeamId")
+
+        # Display name defaults to original (un-lowered) referenced_table
+        label_dict = lookup.display_name.to_dict()
+        self.assertEqual(label_dict["LocalizedLabels"][0]["Label"], "new_SQLTeam")
+
     def test_returns_result(self):
         """Test that the method returns the result from create_one_to_many_relationship."""
         expected_result = {