diff --git a/python/sdssdb/sqlalchemy/archive/__init__.py b/python/sdssdb/sqlalchemy/archive/__init__.py
index d6e60f28..ff260de9 100644
--- a/python/sdssdb/sqlalchemy/archive/__init__.py
+++ b/python/sdssdb/sqlalchemy/archive/__init__.py
@@ -8,20 +8,15 @@
 # @Last modified by: José Sánchez-Gallego (gallegoj@uw.edu)
 # @Last Modified time: 2018-10-10 11:25:13
 
-from __future__ import print_function, division, absolute_import
+from sqlalchemy.ext.declarative import DeferredReflection
+from sqlalchemy.orm import DeclarativeBase
 
 from sdssdb.connection import SQLADatabaseConnection
-from sqlalchemy.ext.declarative import declarative_base, DeferredReflection
 from sdssdb.sqlalchemy import BaseModel
 
 # we need a shared common Base when joining across multiple schema
-ArchiveBase = declarative_base(
-    cls=(
-        DeferredReflection,
-        BaseModel,
-    )
-)
-
+class ArchiveBase(DeferredReflection, BaseModel, DeclarativeBase):
+    pass
 
 class ArchiveDatabaseConnection(SQLADatabaseConnection):
     dbname = "archive"
diff --git a/python/sdssdb/sqlalchemy/archive/sas.py b/python/sdssdb/sqlalchemy/archive/sas.py
index 574e8201..176510fe 100644
--- a/python/sdssdb/sqlalchemy/archive/sas.py
+++ b/python/sdssdb/sqlalchemy/archive/sas.py
@@ -12,15 +12,14 @@
 
 import pathlib
 from sdssdb.sqlalchemy.archive import database, ArchiveBase
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
-from sqlalchemy.orm import relationship, Session
+from sqlalchemy.orm import declared_attr, relationship, Session
 from sqlalchemy.ext.hybrid import hybrid_property
 from sqlalchemy import func
 
 SCHEMA = "sas"
 
 
-class Base(AbstractConcreteBase, ArchiveBase):
+class Base(ArchiveBase):
     __abstract__ = True
     _schema = SCHEMA
     _relations = "define_relations"
diff --git a/python/sdssdb/sqlalchemy/mangadb/__init__.py b/python/sdssdb/sqlalchemy/mangadb/__init__.py
index 6e95ad8d..aff3265a 100644
--- a/python/sdssdb/sqlalchemy/mangadb/__init__.py
+++ b/python/sdssdb/sqlalchemy/mangadb/__init__.py
@@ -8,20 +8,15 @@
 # @Last modified by: José Sánchez-Gallego (gallegoj@uw.edu)
 # @Last Modified time: 2018-10-10 11:25:13
 
-from __future__ import print_function, division, absolute_import
+from sqlalchemy.ext.declarative import DeferredReflection
+from sqlalchemy.orm import DeclarativeBase
 
 from sdssdb.connection import SQLADatabaseConnection
-from sqlalchemy.ext.declarative import declarative_base, DeferredReflection
 from sdssdb.sqlalchemy import BaseModel
 
 # we need a shared common Base when joining across multiple schema
-MangaBase = declarative_base(
-    cls=(
-        DeferredReflection,
-        BaseModel,
-    )
-)
-
+class MangaBase(DeferredReflection, BaseModel, DeclarativeBase):
+    pass
 
 class MANGAdbDatabaseConnection(SQLADatabaseConnection):
     dbname = "manga"
diff --git a/python/sdssdb/sqlalchemy/mangadb/auxdb.py b/python/sdssdb/sqlalchemy/mangadb/auxdb.py
index 5904714e..d27ff0d1 100644
--- a/python/sdssdb/sqlalchemy/mangadb/auxdb.py
+++ b/python/sdssdb/sqlalchemy/mangadb/auxdb.py
@@ -12,13 +12,12 @@
 
 from sdssdb.sqlalchemy.mangadb import MangaBase, database
 from sdssdb.sqlalchemy.mangadb.datadb import Cube
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
-from sqlalchemy.orm import relationship
+from sqlalchemy.orm import declared_attr, relationship
 from sqlalchemy.schema import Column
 from sqlalchemy.types import JSON
 
 
-class Base(AbstractConcreteBase, MangaBase):
+class Base(MangaBase):
     __abstract__ = True
     _schema = "mangaauxdb"
 
diff --git a/python/sdssdb/sqlalchemy/mangadb/dapdb.py b/python/sdssdb/sqlalchemy/mangadb/dapdb.py
index a9d04061..3fa31b33 100644
--- a/python/sdssdb/sqlalchemy/mangadb/dapdb.py
+++ b/python/sdssdb/sqlalchemy/mangadb/dapdb.py
@@ -15,16 +15,15 @@
 from sdssdb.sqlalchemy.mangadb import MangaBase, datadb, database
 from sqlalchemy import Column, Float, and_, case, cast, select
 from sqlalchemy.engine import reflection
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
 from sqlalchemy.ext.hybrid import hybrid_property
-from sqlalchemy.orm import relationship
+from sqlalchemy.orm import declared_attr, relationship
 from sqlalchemy.types import Integer
 
 
 SCHEMA = "mangadapdb"
 
 
-class Base(AbstractConcreteBase, MangaBase):
+class Base(MangaBase):
     __abstract__ = True
     _schema = SCHEMA
     _relations = "define_relations"
diff --git a/python/sdssdb/sqlalchemy/mangadb/datadb.py b/python/sdssdb/sqlalchemy/mangadb/datadb.py
index a19726bf..4d46578b 100644
--- a/python/sdssdb/sqlalchemy/mangadb/datadb.py
+++ b/python/sdssdb/sqlalchemy/mangadb/datadb.py
@@ -21,9 +21,8 @@
 from sqlalchemy import and_, func, select
 from sqlalchemy.dialects.postgresql import ARRAY
 from sqlalchemy.engine import reflection
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
 from sqlalchemy.ext.hybrid import hybrid_method, hybrid_property
-from sqlalchemy.orm import deferred, relationship
+from sqlalchemy.orm import declared_attr, deferred, relationship
 from sqlalchemy.schema import Column
 from sqlalchemy.sql import column
 from sqlalchemy.types import Float, Integer, String
@@ -32,7 +31,7 @@
 SCHEMA = "mangadatadb"
 
 
-class Base(AbstractConcreteBase, MangaBase):
+class Base(MangaBase):
     __abstract__ = True
     _schema = SCHEMA
     _relations = "define_relations"
diff --git a/python/sdssdb/sqlalchemy/mangadb/sampledb.py b/python/sdssdb/sqlalchemy/mangadb/sampledb.py
index ab9d2cf1..a9c80648 100644
--- a/python/sdssdb/sqlalchemy/mangadb/sampledb.py
+++ b/python/sdssdb/sqlalchemy/mangadb/sampledb.py
@@ -17,10 +17,9 @@
 import numpy as np
 from sdssdb.sqlalchemy.mangadb import MangaBase, database
 from sqlalchemy import Float, ForeignKey, ForeignKeyConstraint, case, cast, func
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
 from sqlalchemy.ext.hybrid import hybrid_method, hybrid_property
 from sqlalchemy.inspection import inspect as sa_inspect
-from sqlalchemy.orm import backref, relationship
+from sqlalchemy.orm import backref, declared_attr, relationship
 from sqlalchemy.schema import Column
 from sqlalchemy.types import Integer
 
@@ -34,7 +33,7 @@
 SCHEMA = "mangasampledb"
 
 
-class Base(AbstractConcreteBase, MangaBase):
+class Base(MangaBase):
     __abstract__ = True
     _schema = SCHEMA
     _relations = "define_relations"
diff --git a/python/sdssdb/sqlalchemy/operationsdb/__init__.py b/python/sdssdb/sqlalchemy/operationsdb/__init__.py
index 61e0e21a..f1ef23a9 100644
--- a/python/sdssdb/sqlalchemy/operationsdb/__init__.py
+++ b/python/sdssdb/sqlalchemy/operationsdb/__init__.py
@@ -1,16 +1,13 @@
+from sqlalchemy.ext.declarative import DeferredReflection
+from sqlalchemy.orm import DeclarativeBase
+
 from sdssdb.connection import SQLADatabaseConnection
-from sqlalchemy.ext.declarative import declarative_base, DeferredReflection
 from sdssdb.sqlalchemy import BaseModel
 
 
 # we need a shared common Base when joining across multiple schema
-OperationsBase = declarative_base(
-    cls=(
-        DeferredReflection,
-        BaseModel,
-    )
-)
-
+class OperationsBase(DeferredReflection, BaseModel, DeclarativeBase):
+    pass
 
 class OperationsDBConnection(SQLADatabaseConnection):
     base = OperationsBase
diff --git a/python/sdssdb/sqlalchemy/operationsdb/apogeeqldb.py b/python/sdssdb/sqlalchemy/operationsdb/apogeeqldb.py
index 135421cf..4b7a6be2 100644
--- a/python/sdssdb/sqlalchemy/operationsdb/apogeeqldb.py
+++ b/python/sdssdb/sqlalchemy/operationsdb/apogeeqldb.py
@@ -7,15 +7,14 @@
 # @License: BSD 3-clause (http://www.opensource.org/licenses/BSD-3-Clause)
 
 from sqlalchemy import Column, ForeignKey, Integer
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
-from sqlalchemy.orm import relationship
+from sqlalchemy.orm import declared_attr, relationship
 
 from sdssdb.sqlalchemy.operationsdb import OperationsBase, database
 
 from . import platedb
 
 
-class Base(AbstractConcreteBase, OperationsBase):
+class Base(OperationsBase):
     __abstract__ = True
     _schema = "apogeeqldb"
     _relations = "define_relations"
diff --git a/python/sdssdb/sqlalchemy/operationsdb/mangadb.py b/python/sdssdb/sqlalchemy/operationsdb/mangadb.py
index 70ad5eaa..7be06436 100644
--- a/python/sdssdb/sqlalchemy/operationsdb/mangadb.py
+++ b/python/sdssdb/sqlalchemy/operationsdb/mangadb.py
@@ -10,15 +10,14 @@
 from decimal import Decimal
 
 from astropy.time import Time
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
-from sqlalchemy.orm import backref, relationship
+from sqlalchemy.orm import backref, declared_attr, relationship
 
 from sdssdb.sqlalchemy.operationsdb import OperationsBase, database, platedb
 
 from .tools import dateObs2HA as ha
 
 
-class MangaDBBase(AbstractConcreteBase, OperationsBase):
+class MangaDBBase(OperationsBase):
     __abstract__ = True
     _schema = "mangadb"
     _relations = "define_relations"
diff --git a/python/sdssdb/sqlalchemy/operationsdb/platedb.py b/python/sdssdb/sqlalchemy/operationsdb/platedb.py
index 6334b609..0b4b8096 100644
--- a/python/sdssdb/sqlalchemy/operationsdb/platedb.py
+++ b/python/sdssdb/sqlalchemy/operationsdb/platedb.py
@@ -13,8 +13,7 @@
 
 import sqlalchemy
 from sqlalchemy import func
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
-from sqlalchemy.orm import relationship
+from sqlalchemy.orm import declared_attr, relationship
 from sqlalchemy.orm.exc import MultipleResultsFound, NoResultFound
 from sqlalchemy.orm.session import Session
 
@@ -32,7 +31,7 @@
 warnings.filterwarnings("ignore", ".*Did not recognize type*")
 
 
-class Base(AbstractConcreteBase, OperationsBase):
+class Base(OperationsBase):
     __abstract__ = True
     _schema = "platedb"
     _relations = "define_relations"
diff --git a/python/sdssdb/sqlalchemy/sdss5db/astradb.py b/python/sdssdb/sqlalchemy/sdss5db/astradb.py
index f42220f2..9ecb2fae 100644
--- a/python/sdssdb/sqlalchemy/sdss5db/astradb.py
+++ b/python/sdssdb/sqlalchemy/sdss5db/astradb.py
@@ -3,7 +3,6 @@
 # this file was autogenerated with sqlacodegen and then adapted for sdssdb
 # flake8: noqa: E501,E741
 
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
 from sqlalchemy import (
     ARRAY,
     BigInteger,
@@ -18,7 +17,7 @@
     Text,
     text,
 )
-from sqlalchemy.orm import relationship
+from sqlalchemy.orm import declared_attr, relationship
 
 from sdssdb.sqlalchemy.sdss5db import SDSS5dbBase, database
 
@@ -26,7 +25,7 @@
 SCHEMA = "astra_050"
 
 
-class Base(AbstractConcreteBase, SDSS5dbBase):
+class Base(SDSS5dbBase):
     __abstract__ = True
     _schema = SCHEMA
     _relations = "define_relations"
diff --git a/python/sdssdb/sqlalchemy/sdss5db/opsdb.py b/python/sdssdb/sqlalchemy/sdss5db/opsdb.py
index 3776183e..a6a3f74a 100644
--- a/python/sdssdb/sqlalchemy/sdss5db/opsdb.py
+++ b/python/sdssdb/sqlalchemy/sdss5db/opsdb.py
@@ -20,13 +20,12 @@
     Text,
     text,
 )
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
-from sqlalchemy.orm import relationship
+from sqlalchemy.orm import declared_attr, relationship
 
 from sdssdb.sqlalchemy.sdss5db import SDSS5dbBase, database
 
 
-class Base(AbstractConcreteBase, SDSS5dbBase):
+class Base(SDSS5dbBase):
     __abstract__ = True
     _schema = "opsdb_apo" if os.getenv("OBSERVATORY") == "APO" else "opsdb_lco"
     _relations = "define_relations"
diff --git a/python/sdssdb/sqlalchemy/sdss5db/targetdb.py b/python/sdssdb/sqlalchemy/sdss5db/targetdb.py
index f852a2bb..2e9c4764 100644
--- a/python/sdssdb/sqlalchemy/sdss5db/targetdb.py
+++ b/python/sdssdb/sqlalchemy/sdss5db/targetdb.py
@@ -21,8 +21,7 @@
     text,
 )
 from sqlalchemy.dialects.postgresql import UUID
-from sqlalchemy.ext.declarative import AbstractConcreteBase, declared_attr
-from sqlalchemy.orm import relationship
+from sqlalchemy.orm import declared_attr, relationship
 
 from sdssdb.sqlalchemy.sdss5db import SDSS5dbBase, database
 
@@ -30,7 +29,7 @@
 SCHEMA = "targetdb"
 
 
-class Base(AbstractConcreteBase, SDSS5dbBase):
+class Base(SDSS5dbBase):
     __abstract__ = True
     _schema = SCHEMA
     _relations = "define_relations"