fix: handle PostgreSQL enum types and USER-DEFINED columns

- Add udt_name to column query and use it for USER-DEFINED types
- Qualify enum types with schema name in FK column definitions
- PostgreSQL enums need full "schema"."enum_type" qualification

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

Author: dimitri-yatsenko

src/datajoint/adapters/postgres.py

@@ -718,7 +718,7 @@ def get_columns_sql(self, schema_name: str, table_name: str) -> str:
         table_str = self.quote_string(table_name)
         regclass_expr = f"({schema_str} || '.' || {table_str})::regclass"
         return (
-            f"SELECT c.column_name, c.data_type, c.is_nullable, c.column_default, "
+            f"SELECT c.column_name, c.data_type, c.udt_name, c.is_nullable, c.column_default, "
             f"c.character_maximum_length, c.numeric_precision, c.numeric_scale, "
             f"col_description({regclass_expr}, c.ordinal_position) as column_comment "
             f"FROM information_schema.columns c "
@@ -847,9 +847,14 @@ def parse_column_info(self, row: dict[str, Any]) -> dict[str, Any]:
             Standardized column info with keys:
             name, type, nullable, default, comment, key, extra
         """
+        # For user-defined types (enums), use udt_name instead of data_type
+        # PostgreSQL reports enums as "USER-DEFINED" in data_type
+        data_type = row["data_type"]
+        if data_type == "USER-DEFINED":
+            data_type = row["udt_name"]
         return {
             "name": row["column_name"],
-            "type": row["data_type"],
+            "type": data_type,
             "nullable": row["is_nullable"] == "YES",
             "default": row["column_default"],
             "comment": row.get("column_comment"),  # Retrieved via col_description()

src/datajoint/declare.py

@@ -267,9 +267,14 @@ def compile_foreign_key(
 
             # Build foreign key column definition using adapter
             parent_attr = ref.heading[attr]
+            sql_type = parent_attr.sql_type
+            # For PostgreSQL enum types, qualify with schema name
+            # Enum type names start with "enum_" (generated hash-based names)
+            if sql_type.startswith("enum_") and adapter.backend == "postgresql":
+                sql_type = f"{adapter.quote_identifier(ref.database)}.{adapter.quote_identifier(sql_type)}"
             col_def = adapter.format_column_definition(
                 name=attr,
-                sql_type=parent_attr.sql_type,
+                sql_type=sql_type,
                 nullable=is_nullable,
                 default=None,
                 comment=parent_attr.sql_comment,