Address PR review: move create_lookup_field to client, remove extensions

- Move create_lookup_field from extensions/relationships.py to DataverseClient method
- Remove extensions/ directory entirely (src and tests)
- Use tight type definitions instead of Any for relationship methods
- Remove .NET SDK references from docstrings
- Empty src models/__init__.py, add docstring to tests models/__init__.py
- Add M:N relationship query to example
- Add 12 unit tests for create_lookup_field

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: tpellissier

examples/advanced/relationships.py

@@ -6,7 +6,7 @@
 
 This example demonstrates:
 - Creating one-to-many relationships using the core SDK API
-- Creating lookup fields using the convenience extension helper
+- Creating lookup fields using the convenience method
 - Creating many-to-many relationships
 - Querying and deleting relationships
 - Working with relationship metadata types
@@ -29,7 +29,6 @@
     CascadeConfiguration,
     AssociatedMenuConfiguration,
 )
-from PowerPlatform.Dataverse.extensions.relationships import create_lookup_field
 
 
 # Simple logging helper
@@ -245,19 +244,18 @@ def main():
     rel_id_1 = result["relationship_id"]
 
     # ============================================================================
-    # 5. CREATE LOOKUP FIELD (Extension Helper)
+    # 5. CREATE LOOKUP FIELD (Convenience Method)
     # ============================================================================
     print("\n" + "=" * 80)
-    print("5. Create Lookup Field (Extension Helper)")
+    print("5. Create Lookup Field (Convenience Method)")
     print("=" * 80)
 
     log_call("Creating lookup field on Employee referencing Contact as Manager")
 
-    # Use the convenience helper for simpler scenarios
+    # Use the convenience method for simpler scenarios
     # An Employee has a Manager (who is a Contact in the system)
     result2 = backoff(
-        lambda: create_lookup_field(
-            client,
+        lambda: client.create_lookup_field(
             referencing_table=emp_table["table_logical_name"],
             lookup_field_name="new_ManagerId",
             referenced_table="contact",
@@ -268,7 +266,7 @@ def main():
         )
     )
 
-    print(f"[OK] Created lookup using helper: {result2['lookup_schema_name']}")
+    print(f"[OK] Created lookup using convenience method: {result2['lookup_schema_name']}")
     print(f"  Relationship: {result2['relationship_schema_name']}")
 
     rel_id_2 = result2["relationship_id"]
@@ -317,7 +315,7 @@ def main():
     print("7. Query Relationship Metadata")
     print("=" * 80)
 
-    log_call("Retrieving relationship by schema name")
+    log_call("Retrieving 1:N relationship by schema name")
 
     rel_metadata = client.get_relationship("new_Department_Employee")
     if rel_metadata:
@@ -328,6 +326,17 @@ def main():
     else:
         print("  Relationship not found")
 
+    log_call("Retrieving M:N relationship by schema name")
+
+    m2m_metadata = client.get_relationship("new_employee_project")
+    if m2m_metadata:
+        print(f"[OK] Found relationship: {m2m_metadata.get('SchemaName')}")
+        print(f"  Type: {m2m_metadata.get('@odata.type')}")
+        print(f"  Entity 1: {m2m_metadata.get('Entity1LogicalName')}")
+        print(f"  Entity 2: {m2m_metadata.get('Entity2LogicalName')}")
+    else:
+        print("  Relationship not found")
+
     # ============================================================================
     # 8. CLEANUP
     # ============================================================================

src/PowerPlatform/Dataverse/client.py

@@ -11,6 +11,14 @@
 from .core._auth import _AuthManager
 from .core.config import DataverseConfig
 from .data._odata import _ODataClient
+from .models.metadata import (
+    LookupAttributeMetadata,
+    OneToManyRelationshipMetadata,
+    ManyToManyRelationshipMetadata,
+    Label,
+    LocalizedLabel,
+    CascadeConfiguration,
+)
 
 
 class DataverseClient:
@@ -701,16 +709,15 @@ def flush_cache(self, kind) -> int:
     # Relationship operations
     def create_one_to_many_relationship(
         self,
-        lookup: Any,
-        relationship: Any,
+        lookup: LookupAttributeMetadata,
+        relationship: OneToManyRelationshipMetadata,
         solution_unique_name: Optional[str] = None,
     ) -> Dict[str, Any]:
         """
         Create a one-to-many relationship between tables.
 
         This operation creates both the relationship and the lookup attribute
-        on the referencing table. It mirrors the CreateOneToManyRequest from
-        the .NET SDK.
+        on the referencing table.
 
         :param lookup: Metadata defining the lookup attribute.
         :type lookup: ~PowerPlatform.Dataverse.models.metadata.LookupAttributeMetadata
@@ -768,15 +775,14 @@ def create_one_to_many_relationship(
 
     def create_many_to_many_relationship(
         self,
-        relationship: Any,
+        relationship: ManyToManyRelationshipMetadata,
         solution_unique_name: Optional[str] = None,
     ) -> Dict[str, Any]:
         """
         Create a many-to-many relationship between tables.
 
         This operation creates a many-to-many relationship and an intersect table
-        to manage the relationship. It mirrors the CreateManyToManyRequest from
-        the .NET SDK.
+        to manage the relationship.
 
         :param relationship: Metadata defining the many-to-many relationship.
         :type relationship: ~PowerPlatform.Dataverse.models.metadata.ManyToManyRelationshipMetadata
@@ -854,5 +860,92 @@ def get_relationship(self, schema_name: str) -> Optional[Dict[str, Any]]:
         with self._scoped_odata() as od:
             return od._get_relationship(schema_name)
 
+    def create_lookup_field(
+        self,
+        referencing_table: str,
+        lookup_field_name: str,
+        referenced_table: str,
+        display_name: Optional[str] = None,
+        description: Optional[str] = None,
+        required: bool = False,
+        cascade_delete: str = "RemoveLink",
+        solution_unique_name: Optional[str] = None,
+        language_code: int = 1033,
+    ) -> Dict[str, Any]:
+        """
+        Create a simple lookup field relationship.
+
+        This is a convenience method that wraps :meth:`create_one_to_many_relationship`
+        for the common case of adding a lookup field to an existing table.
+
+        :param referencing_table: Logical name of the table that will have the lookup field (child table).
+        :type referencing_table: :class:`str`
+        :param lookup_field_name: Schema name for the lookup field (e.g., ``"new_AccountId"``).
+        :type lookup_field_name: :class:`str`
+        :param referenced_table: Logical name of the table being referenced (parent table).
+        :type referenced_table: :class:`str`
+        :param display_name: Display name for the lookup field. Defaults to the referenced table name.
+        :type display_name: :class:`str` or None
+        :param description: Optional description for the lookup field.
+        :type description: :class:`str` or None
+        :param required: Whether the lookup is required. Defaults to ``False``.
+        :type required: :class:`bool`
+        :param cascade_delete: Delete behavior (``"RemoveLink"``, ``"Cascade"``, ``"Restrict"``).
+            Defaults to ``"RemoveLink"``.
+        :type cascade_delete: :class:`str`
+        :param solution_unique_name: Optional solution to add the relationship to.
+        :type solution_unique_name: :class:`str` or None
+        :param language_code: Language code for labels. Defaults to 1033 (English).
+        :type language_code: :class:`int`
+
+        :return: Dictionary with ``relationship_id``, ``lookup_schema_name``, and related metadata.
+        :rtype: :class:`dict`
+
+        :raises ~PowerPlatform.Dataverse.core.errors.HttpError: If the Web API request fails.
+
+        Example:
+            Create a simple lookup field::
+
+                result = client.create_lookup_field(
+                    referencing_table="new_order",
+                    lookup_field_name="new_AccountId",
+                    referenced_table="account",
+                    display_name="Account",
+                    required=True,
+                    cascade_delete="RemoveLink"
+                )
+
+                print(f"Created lookup: {result['lookup_schema_name']}")
+        """
+        # Build the label
+        localized_labels = [LocalizedLabel(label=display_name or referenced_table, language_code=language_code)]
+
+        # Build the lookup attribute
+        lookup = LookupAttributeMetadata(
+            schema_name=lookup_field_name,
+            display_name=Label(localized_labels=localized_labels),
+            required_level="ApplicationRequired" if required else "None",
+        )
+
+        # Add description if provided
+        if description:
+            lookup.description = Label(
+                localized_labels=[LocalizedLabel(label=description, language_code=language_code)]
+            )
+
+        # Generate a relationship name
+        relationship_name = f"{referenced_table}_{referencing_table}_{lookup_field_name}"
+
+        # Build the relationship metadata
+        relationship = OneToManyRelationshipMetadata(
+            schema_name=relationship_name,
+            referenced_entity=referenced_table,
+            referencing_entity=referencing_table,
+            referenced_attribute=f"{referenced_table}id",
+            cascade_configuration=CascadeConfiguration(delete=cascade_delete),
+        )
+
+        return self.create_one_to_many_relationship(lookup, relationship, solution_unique_name)
+
 
 __all__ = ["DataverseClient"]

src/PowerPlatform/Dataverse/extensions/__init__.py

@@ -1,26 +1,2 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT license.
-
-"""
-Data models and type definitions for the Dataverse SDK.
-"""
-
-from .metadata import (
-    LocalizedLabel,
-    Label,
-    CascadeConfiguration,
-    AssociatedMenuConfiguration,
-    LookupAttributeMetadata,
-    OneToManyRelationshipMetadata,
-    ManyToManyRelationshipMetadata,
-)
-
-__all__ = [
-    "LocalizedLabel",
-    "Label",
-    "CascadeConfiguration",
-    "AssociatedMenuConfiguration",
-    "LookupAttributeMetadata",
-    "OneToManyRelationshipMetadata",
-    "ManyToManyRelationshipMetadata",
-]