diff --git a/kcidb_io/schema/abstract.py b/kcidb_io/schema/abstract.py
index 8262809..05c9829 100644
--- a/kcidb_io/schema/abstract.py
+++ b/kcidb_io/schema/abstract.py
@@ -57,6 +57,13 @@ def __init__(cls, name, bases, _dict, **kwargs):
                        all(isinstance(e, str) for e in v)
                        for k, v in cls.graph.items())
             assert "" in cls.graph
+            assert isinstance(cls.id_fields, dict)
+            assert set(cls.graph) - {""} == set(cls.id_fields)
+            assert all(isinstance(fields, dict) and
+                       len(fields) > 0 and
+                       all(isinstance(n, str) and isinstance(t, type)
+                           for n, t in fields.items())
+                       for fields in cls.id_fields.values())
 
     def __str__(cls):
         return f"v{cls.major}.{cls.minor}"
@@ -133,6 +140,8 @@ class Version(ABC, metaclass=MetaVersion):
     # list of the same, with the empty string mapping to a list of topmost
     # object list names.
     graph = None
+    # A map of object names and dictionaries of their ID fields and types
+    id_fields = None
 
     @classmethod
     @abstractmethod
diff --git a/kcidb_io/schema/test_abstract.py b/kcidb_io/schema/test_abstract.py
index 6e844b2..f41e86b 100644
--- a/kcidb_io/schema/test_abstract.py
+++ b/kcidb_io/schema/test_abstract.py
@@ -15,12 +15,14 @@ class V1(Version):
             minor = 0
             json = dict(title="v1")
             graph = {"": []}
+            id_fields = {}
 
         class V2(V1):
             major = 2
             minor = 0
             json = dict(title="v2")
             graph = {"": []}
+            id_fields = {}
 
             @staticmethod
             def _inherit(data):
@@ -31,12 +33,14 @@ class V2D1(V2):
             minor = 1
             json = dict(title="v2.1")
             graph = {"": []}
+            id_fields = {}
 
         class V3(V2D1):
             major = 3
             minor = 0
             json = dict(title="v3")
             graph = {"": []}
+            id_fields = {}
 
             @staticmethod
             def _inherit(data):
@@ -138,12 +142,14 @@ class V1(Version):
             minor = 0
             json = dict(title="v1")
             graph = {"": []}
+            id_fields = {}
 
         class V2A(V1):
             major = 2
             minor = 0
             json = dict(title="v2a")
             graph = {"": []}
+            id_fields = {}
 
             @staticmethod
             def _inherit(data):
@@ -154,6 +160,7 @@ class V2B(V1):
             minor = 0
             json = dict(title="v2b")
             graph = {"": []}
+            id_fields = {}
 
             @staticmethod
             def _inherit(data):
diff --git a/kcidb_io/schema/v01_01.py b/kcidb_io/schema/v01_01.py
index 6f0d98d..deb4d8c 100644
--- a/kcidb_io/schema/v01_01.py
+++ b/kcidb_io/schema/v01_01.py
@@ -579,6 +579,12 @@ class Version(AbstractVersion):
         "builds": ["tests"],
         "tests": []
     }
+    # A map of object names and dictionaries of their ID fields and types
+    id_fields = dict(
+        revisions=dict(origin=str, origin_id=str),
+        builds=dict(origin=str, origin_id=str),
+        tests=dict(origin=str, origin_id=str),
+    )
 
     @classmethod
     def _get_version(cls, data):
diff --git a/kcidb_io/schema/v02_00.py b/kcidb_io/schema/v02_00.py
index be6ba41..05ff7ef 100644
--- a/kcidb_io/schema/v02_00.py
+++ b/kcidb_io/schema/v02_00.py
@@ -549,6 +549,13 @@ class Version(PreviousVersion):
         "tests": []
     }
 
+    # A map of object names and dictionaries of their ID fields and types
+    id_fields = dict(
+        revisions=dict(id=str),
+        builds=dict(id=str),
+        tests=dict(id=str),
+    )
+
     @classmethod
     def _get_version(cls, data):
         """
diff --git a/kcidb_io/schema/v04_00.py b/kcidb_io/schema/v04_00.py
index 5dd5ddd..648ad6f 100644
--- a/kcidb_io/schema/v04_00.py
+++ b/kcidb_io/schema/v04_00.py
@@ -690,6 +690,13 @@ class Version(PreviousVersion):
         "tests": []
     }
 
+    # A map of object names and dictionaries of their ID fields and types
+    id_fields = dict(
+        checkouts=dict(id=str),
+        builds=dict(id=str),
+        tests=dict(id=str),
+    )
+
     @staticmethod
     def _inherit(data):
         """
diff --git a/kcidb_io/schema/v04_01.py b/kcidb_io/schema/v04_01.py
index f1cd410..4ca23eb 100644
--- a/kcidb_io/schema/v04_01.py
+++ b/kcidb_io/schema/v04_01.py
@@ -898,3 +898,12 @@ class Version(PreviousVersion):
         "issues": ["incidents"],
         "incidents": [],
     }
+
+    # A map of object names and dictionaries of their ID fields and types
+    id_fields = dict(
+        checkouts=dict(id=str),
+        builds=dict(id=str),
+        tests=dict(id=str),
+        issues=dict(id=str),
+        incidents=dict(id=str),
+    )