Add extended table metadata retrieval and models for columns and option sets

- Implemented methods to fetch detailed metadata for tables, including columns and relationships.
- Introduced `ColumnMetadata`, `OptionItem`, and `OptionSetInfo` models to represent column and option set data structures.
- Updated `get` method in `TableOperations` to support optional parameters for including columns and relationships in the response.
- Enhanced tests to cover new functionality and ensure backward compatibility.

This update improves the SDK's ability to interact with Dataverse metadata, providing richer data for developers.

Author: maksii

.claude/skills/dataverse-sdk-use/SKILL.md

@@ -223,6 +223,63 @@ for table in tables:
     print(table)
 ```
 
+#### Get Extended Table Metadata
+```python
+# Get table with column metadata
+info = client.tables.get("account", include_columns=True)
+for col in info["columns"]:
+    print(f"{col.logical_name} ({col.attribute_type})")
+
+# Get table with relationship metadata
+info = client.tables.get("account", include_relationships=True)
+
+# Get specific entity properties
+info = client.tables.get("account", select=["DisplayName", "Description"])
+```
+
+#### List Columns
+```python
+from PowerPlatform.Dataverse.models.metadata import ColumnMetadata
+
+columns = client.tables.get_columns("account")
+for col in columns:
+    print(f"{col.schema_name}: {col.attribute_type} (required: {col.required_level})")
+
+# Filter to specific column types (OData syntax, fully-qualified enum)
+picklists = client.tables.get_columns(
+    "account",
+    filter="AttributeType eq Microsoft.Dynamics.CRM.AttributeTypeCode'Picklist'",
+)
+```
+
+#### Get Single Column
+```python
+col = client.tables.get_column("account", "emailaddress1")
+if col:
+    print(f"Type: {col.attribute_type}, Required: {col.required_level}")
+```
+
+#### Get Column Options (Picklist/Choice Values)
+```python
+from PowerPlatform.Dataverse.models.metadata import OptionSetInfo
+
+options = client.tables.get_column_options("account", "accountcategorycode")
+if options:
+    for opt in options.options:
+        print(f"  Value={opt.value}, Label={opt.label}")
+```
+
+#### List Table Relationships
+```python
+# All relationships
+rels = client.tables.list_relationships("account")
+
+# Specific type: "one_to_many" / "1:N", "many_to_one" / "N:1", "many_to_many" / "N:N"
+rels = client.tables.list_relationships("account", relationship_type="one_to_many")
+for rel in rels:
+    print(f"{rel['SchemaName']}: {rel.get('ReferencingEntity')}")
+```
+
 #### Delete Tables
 ```python
 client.tables.delete("new_Product")

README.md

@@ -309,6 +309,40 @@ client.tables.remove_columns("new_Product", ["new_Category"])
 client.tables.delete("new_Product")
 ```
 
+```python
+# Get extended table metadata with columns
+info = client.tables.get("account", include_columns=True)
+for col in info["columns"]:
+    print(f"{col.logical_name} ({col.attribute_type})")
+
+# Get extended table metadata with relationships
+info = client.tables.get("account", include_relationships=True)
+for rel in info.get("one_to_many_relationships", []):
+    print(rel["SchemaName"])
+
+# Get specific entity properties
+info = client.tables.get("account", select=["DisplayName", "Description"])
+
+# List all columns of a table
+columns = client.tables.get_columns("account")
+for col in columns:
+    print(f"{col.schema_name}: {col.attribute_type} (required: {col.required_level})")
+
+# Get a specific column's metadata
+col = client.tables.get_column("account", "emailaddress1")
+if col:
+    print(f"Type: {col.attribute_type}, Required: {col.required_level}")
+
+# Get picklist/choice column options
+options = client.tables.get_column_options("account", "accountcategorycode")
+if options:
+    for opt in options.options:
+        print(f"  {opt.value}: {opt.label}")
+
+# List relationships for a table
+rels = client.tables.list_relationships("account", relationship_type="one_to_many")
+```
+
 > **Important**: All custom column names must include the customization prefix value (e.g., `"new_"`).
 > This ensures explicit, predictable naming and aligns with Dataverse metadata requirements.
 

src/PowerPlatform/Dataverse/common/constants.py

@@ -29,3 +29,30 @@
 
 CASCADE_BEHAVIOR_RESTRICT = "Restrict"
 """Prevent the referenced table record from being deleted when referencing table records exist."""
+
+# AttributeMetadata derived type OData identifiers
+# Used when casting Attributes collection to a specific derived type in Web API URLs
+ODATA_TYPE_PICKLIST_ATTRIBUTE = "Microsoft.Dynamics.CRM.PicklistAttributeMetadata"
+ODATA_TYPE_BOOLEAN_ATTRIBUTE = "Microsoft.Dynamics.CRM.BooleanAttributeMetadata"
+ODATA_TYPE_MULTISELECT_PICKLIST_ATTRIBUTE = "Microsoft.Dynamics.CRM.MultiSelectPicklistAttributeMetadata"
+ODATA_TYPE_STRING_ATTRIBUTE = "Microsoft.Dynamics.CRM.StringAttributeMetadata"
+ODATA_TYPE_INTEGER_ATTRIBUTE = "Microsoft.Dynamics.CRM.IntegerAttributeMetadata"
+ODATA_TYPE_DECIMAL_ATTRIBUTE = "Microsoft.Dynamics.CRM.DecimalAttributeMetadata"
+ODATA_TYPE_DOUBLE_ATTRIBUTE = "Microsoft.Dynamics.CRM.DoubleAttributeMetadata"
+ODATA_TYPE_MONEY_ATTRIBUTE = "Microsoft.Dynamics.CRM.MoneyAttributeMetadata"
+ODATA_TYPE_DATETIME_ATTRIBUTE = "Microsoft.Dynamics.CRM.DateTimeAttributeMetadata"
+ODATA_TYPE_MEMO_ATTRIBUTE = "Microsoft.Dynamics.CRM.MemoAttributeMetadata"
+ODATA_TYPE_FILE_ATTRIBUTE = "Microsoft.Dynamics.CRM.FileAttributeMetadata"
+
+# Attribute type code values returned in the AttributeType property of attribute metadata
+ATTRIBUTE_TYPE_PICKLIST = "Picklist"
+ATTRIBUTE_TYPE_BOOLEAN = "Boolean"
+ATTRIBUTE_TYPE_STRING = "String"
+ATTRIBUTE_TYPE_INTEGER = "Integer"
+ATTRIBUTE_TYPE_DECIMAL = "Decimal"
+ATTRIBUTE_TYPE_DOUBLE = "Double"
+ATTRIBUTE_TYPE_MONEY = "Money"
+ATTRIBUTE_TYPE_DATETIME = "DateTime"
+ATTRIBUTE_TYPE_MEMO = "Memo"
+ATTRIBUTE_TYPE_LOOKUP = "Lookup"
+ATTRIBUTE_TYPE_UNIQUEIDENTIFIER = "Uniqueidentifier"