Makign corrections on field selection.

crudkit/core/base.py

@@ -9,13 +9,26 @@ class CRUDMixin:
     created_at = Column(DateTime, default=func.now(), nullable=False)
     updated_at = Column(DateTime, default=func.now(), nullable=False, onupdate=func.now())
 
-    def as_dict(self):
-        # Combine all columns from all inherited tables
+    def as_dict(self, fields: list[str] | None = None):
+        """
+        Serialize mapped columns. Honors projection if either:
+            - 'fields' is passed explicitly, or
+            -
+        """
+        allowed = None
+        if fields:
+            allowed = set(fields)
+        else:
+            allowed = getattr(self, "__crudkit_root_fields__", None)
         result = {}
         for cls in self.__class__.__mro__:
-            if hasattr(cls, "__table__"):
-                for column in cls.__table__.columns:
-                    result[column.name] = getattr(self, column.name)
+            if not hasattr(cls, "__table__"):
+                continue
+            for column in cls.__table__.columns:
+                name = column.name
+                if allowed is not None and name not in allowed and name != "id":
+                    continue
+                result[name] = getattr(self, name)
         return result
 
 class Version(Base):