diff --git a/unwind/db.py b/unwind/db.py
index fa035e7..ddbb007 100644
--- a/unwind/db.py
+++ b/unwind/db.py
@@ -1,6 +1,5 @@
 import logging
 import re
-from dataclasses import fields
 from pathlib import Path
 from typing import Iterable, Literal, Optional, Type, TypeVar, Union
 
@@ -8,7 +7,7 @@ import sqlalchemy
 from databases import Database
 
 from . import config
-from .models import Movie, Rating, User, asplain, fromplain, optional_fields
+from .models import Movie, Rating, User, asplain, fields, fromplain, optional_fields
 
 log = logging.getLogger(__name__)
 
diff --git a/unwind/models.py b/unwind/models.py
index 2a60071..2789583 100644
--- a/unwind/models.py
+++ b/unwind/models.py
@@ -1,11 +1,46 @@
 import json
-from dataclasses import asdict, dataclass, field, fields
+from dataclasses import dataclass, field
+from dataclasses import fields as _fields
 from datetime import datetime, timezone
-from typing import Any, ClassVar, Optional, Type, Union, get_args, get_origin
+from typing import (
+    Annotated,
+    Any,
+    ClassVar,
+    Optional,
+    Type,
+    TypeVar,
+    Union,
+    get_args,
+    get_origin,
+)
 
 from .types import ULID
 
 
+def annotations(tp: Type) -> Optional[tuple]:
+    return tp.__metadata__ if hasattr(tp, "__metadata__") else None
+
+
+def fields(class_or_instance):
+    """Like dataclass' `fields` but with extra support for our models.
+
+    This function is a drop-in replacement for dataclass' `fields` and
+    SHOULD be used instead of it everywhere.
+    This function filters out fields marked as `Relation`.  `Relation`
+    fields are meant to allow to store the data referenced by an ID field
+    directly on the instance.
+    """
+
+    # XXX this might be a little slow (not sure), if so, memoize
+
+    for f in _fields(class_or_instance):
+
+        if (attn := annotations(f.type)) and _RelationSentinel in attn:
+            continue  # Relations are ignored
+
+        yield f
+
+
 def is_optional(tp: Type):
     if get_origin(tp) is not Union:
         return False
@@ -34,7 +69,7 @@ def optional_fields(o):
 def asplain(o) -> dict[str, Any]:
     validate(o)
 
-    d = asdict(o)
+    d = {}
     for f in fields(o):
 
         target = f.type
@@ -44,7 +79,7 @@ def asplain(o) -> dict[str, Any]:
         if (otype := get_origin(target)) is not None:
             target = otype
 
-        v = d[f.name]
+        v = getattr(o, f.name)
         if target is ULID:
             d[f.name] = str(v)
         elif target in {datetime}:
@@ -54,7 +89,7 @@ def asplain(o) -> dict[str, Any]:
         elif target in {list}:
             d[f.name] = json.dumps(list(v))
         elif target in {bool, str, int, float, None}:
-            pass
+            d[f.name] = v
         else:
             raise ValueError(f"Unsupported value type: {f.name}: {type(v)}")
 
@@ -123,18 +158,47 @@ class Movie:
     updated: datetime = field(default_factory=utcnow)
 
 
+T = TypeVar("T")
+_RelationSentinel = object()
+"""Mark a model field as containing external data.
+
+For each field marked as a Relation there should be another field on the
+dataclass containing the ID of the linked data.
+The contents of the Relation are ignored or discarded when using
+`asplain`, `fromplain`, and `validate`.
+"""
+Relation = Annotated[Optional[T], _RelationSentinel]
+
+
 @dataclass
 class Rating:
     _table: ClassVar[str] = "ratings"
 
     id: ULID = field(default_factory=ULID)
+
     movie_id: ULID = None
+    movie: Relation[Movie] = None
+
     user_id: ULID = None
+    user: Relation["User"] = None
+
     score: int = None  # range: [0,100]
     rating_date: datetime = None
     favorite: Optional[bool] = None
     finished: Optional[bool] = None
 
+    def __eq__(self, other):
+        """Return wether two Ratings are equal.
+
+        This operation compares all fields as expected, except that it
+        ignores any field marked as Relation.
+        """
+        if type(other) is not type(self):
+            return False
+        return all(
+            getattr(self, f.name) == getattr(other, f.name) for f in fields(self)
+        )
+
 
 @dataclass
 class User: