diff --git a/toardb/stationmeta/models_changelog.py b/toardb/stationmeta/models_changelog.py
index 3848c9756dab4c00db06d7e2aa1a9829da4c6f80..f380265642287e10a4a8b136c349c4bb0561c832 100644
--- a/toardb/stationmeta/models_changelog.py
+++ b/toardb/stationmeta/models_changelog.py
@@ -10,15 +10,12 @@ from .models_core import StationmetaCore
 from toardb.auth_user.models import AuthUser
 from toardb.base import Base
 
-STATIONMETA_CHANGELOG_ID_SEQ = Sequence('stationmeta_changelog_id_seq')  # define sequence explicitly
 class StationmetaChangelog(Base):
     """ Table "public.stationmeta_changelog"
 
     +----------------+--------------------------+-----------+----------+--------------------------------------------------------+
     |     Column     |           Type           | Collation | Nullable |                      Default                           |
     +================+==========================+===========+==========+========================================================+
-    | id             | bigint                   |           | not null | nextval('stationmeta_changelog_id_seq'::regclass)      |
-    +----------------+--------------------------+-----------+----------+--------------------------------------------------------+
     | datetime       | timestamp with time zone |           | not null | now()                                                  |
     +----------------+--------------------------+-----------+----------+--------------------------------------------------------+
     | station_id     | bigint                   |           | not null |                                                        |
@@ -34,7 +31,7 @@ class StationmetaChangelog(Base):
     | author_id      | integer                  |           | not null |                                                        |
     +----------------+--------------------------+-----------+----------+--------------------------------------------------------+
     Indexes:
-     "stationmeta_changelog_pkey" PRIMARY KEY, btree (id)
+     "timeseries_changelog_pkey" PRIMARY KEY, btree (datetime)
     Foreign-key constraints:
      "stationmeta_changelog_author_id_fk_auth_user_id" FOREIGN KEY (author_id) REFERENCES auth_user(id)
      "stationmeta_changelog_station_id_fk_stationmeta_core_id" FOREIGN KEY (station_id) REFERENCES stationmeta_core(id)
@@ -42,8 +39,7 @@ class StationmetaChangelog(Base):
     """
     __tablename__ = 'stationmeta_changelog'
 
-    id = Column(BigInteger, STATIONMETA_CHANGELOG_ID_SEQ, primary_key=True, server_default=STATIONMETA_CHANGELOG_ID_SEQ.next_value())
-    datetime = Column(DateTime(True), nullable=False, server_default=text("now()"))
+    datetime = Column(DateTime(True), primary_key=True, nullable=False, server_default=text("now()"))
     description = Column(Text, nullable=False)
     old_value = Column(String(256), nullable=False)
     new_value = Column(String(256), nullable=False)
diff --git a/toardb/stationmeta/schemas.py b/toardb/stationmeta/schemas.py
index 520d3fcd48ac94ee61206aa29b49859ae9990082..cfb80467f5a4d5c3640050c65ada6a4ebc0179b3 100644
--- a/toardb/stationmeta/schemas.py
+++ b/toardb/stationmeta/schemas.py
@@ -452,7 +452,6 @@ class StationmetaRole(StationmetaRoleBase):
 # ======== StationmetaChangelog =========
 
 class StationmetaChangelogBase(BaseModel):
-    id: int
     datetime: dt.datetime
     description: str
     old_value: str
@@ -463,7 +462,6 @@ class StationmetaChangelogBase(BaseModel):
 
 
 class StationmetaChangelog(StationmetaChangelogBase):
-    id: int
 
     class Config:
         orm_mode = True
diff --git a/toardb/timeseries/models_changelog.py b/toardb/timeseries/models_changelog.py
index 235c464276273271ef3f7b12c7ba049f594fd3f9..6e97f382213207e49fe0aa4959da610e642d0bec 100644
--- a/toardb/timeseries/models_changelog.py
+++ b/toardb/timeseries/models_changelog.py
@@ -10,15 +10,12 @@ from .models_core import Timeseries
 from toardb.auth_user.models import AuthUser
 from toardb.base import Base
 
-TIMESERIES_CHANGELOG_ID_SEQ = Sequence('timeseries_changelog_id_seq')  # define sequence explicitly
 class TimeseriesChangelog(Base):
     """ Table "public.timeseries_changelog"
 
     +----------------+--------------------------+-----------+----------+--------------------------------------------------+
     |     Column     |           Type           | Collation | Nullable |                      Default                     |
     +================+==========================+===========+==========+==================================================+
-    | id             | bigint                   |           | not null | nextval('timeseries_changelog_id_seq'::regclass) |
-    +----------------+--------------------------+-----------+----------+--------------------------------------------------+
     | datetime       | timestamp with time zone |           | not null | now()                                            |
     +----------------+--------------------------+-----------+----------+--------------------------------------------------+
     | timeseries_id  | bigint                   |           | not null |                                                  |
@@ -40,7 +37,7 @@ class TimeseriesChangelog(Base):
     | author_id      | integer                  |           | not null |                                                  |
     +----------------+--------------------------+-----------+----------+--------------------------------------------------+
     Indexes:
-     "timeseries_changelog_pkey" PRIMARY KEY, btree (id)
+     "timeseries_changelog_pkey" PRIMARY KEY, btree (datetime)
     Foreign-key constraints:
      "timeseries_changelog_author_id_fk_auth_user_id" FOREIGN KEY (author_id) REFERENCES auth_user(id)
      "timeseries_changelog_timeseries_id_fk_timeseries_id" FOREIGN KEY (timeseries_id) REFERENCES timeseries(id)
@@ -49,8 +46,7 @@ class TimeseriesChangelog(Base):
 
     __tablename__ = 'timeseries_changelog'
 
-    id = Column(BigInteger, TIMESERIES_CHANGELOG_ID_SEQ, primary_key=True, server_default=TIMESERIES_CHANGELOG_ID_SEQ.next_value())
-    datetime = Column(DateTime(True), nullable=False, server_default=text("now()"))
+    datetime = Column(DateTime(True), primary_key=True, nullable=False, server_default=text("now()"))
     description = Column(Text, nullable=False)
     old_value = Column(String(256), nullable=False)
     new_value = Column(String(256), nullable=False)
diff --git a/toardb/timeseries/schemas.py b/toardb/timeseries/schemas.py
index 8abc5f148abb50624199e2d24df212f6c5ed260d..6be64c7c473090e4ac3967763e5414197510ba8d 100644
--- a/toardb/timeseries/schemas.py
+++ b/toardb/timeseries/schemas.py
@@ -201,7 +201,6 @@ class TimeseriesProgramme(TimeseriesProgrammeBase):
 # ======== TimeseriesChangelog =========
 
 class TimeseriesChangelogBase(BaseModel):
-    id: int
     datetime: dt.datetime
     description: str
     old_value: str
@@ -215,7 +214,6 @@ class TimeseriesChangelogBase(BaseModel):
 
 
 class TimeseriesChangelog(TimeseriesChangelogBase):
-    id: int
 
     class Config:
         orm_mode = True