diff --git a/test/test_core.py b/test/test_core.py
index 3f7d808..ab8db17 100644
--- a/test/test_core.py
+++ b/test/test_core.py
@@ -15,11 +15,9 @@
 from ydb_sqlalchemy.sqlalchemy import types
 
 if sa.__version__ >= "2.":
-    from sqlalchemy import NullPool
-    from sqlalchemy import QueuePool
+    from sqlalchemy import NullPool, QueuePool
 else:
-    from sqlalchemy.pool import NullPool
-    from sqlalchemy.pool import QueuePool
+    from sqlalchemy.pool import NullPool, QueuePool
 
 
 def clear_sql(stm):
diff --git a/test/test_suite.py b/test/test_suite.py
index 0ffa6df..e67af8a 100644
--- a/test/test_suite.py
+++ b/test/test_suite.py
@@ -68,7 +68,6 @@
 from sqlalchemy.testing.suite.test_types import DateTimeTest as _DateTimeTest
 from sqlalchemy.testing.suite.test_types import IntegerTest as _IntegerTest
 from sqlalchemy.testing.suite.test_types import JSONTest as _JSONTest
-
 from sqlalchemy.testing.suite.test_types import NumericTest as _NumericTest
 from sqlalchemy.testing.suite.test_types import StringTest as _StringTest
 from sqlalchemy.testing.suite.test_types import (
diff --git a/ydb_sqlalchemy/__init__.py b/ydb_sqlalchemy/__init__.py
index 55ade24..62f8b58 100644
--- a/ydb_sqlalchemy/__init__.py
+++ b/ydb_sqlalchemy/__init__.py
@@ -1,4 +1,5 @@
-from ._version import VERSION  # noqa: F401
+import ydb_dbapi as dbapi
 from ydb_dbapi import IsolationLevel  # noqa: F401
+
+from ._version import VERSION  # noqa: F401
 from .sqlalchemy import Upsert, types, upsert  # noqa: F401
-import ydb_dbapi as dbapi
diff --git a/ydb_sqlalchemy/sqlalchemy/__init__.py b/ydb_sqlalchemy/sqlalchemy/__init__.py
index 7bdf8f8..d68a009 100644
--- a/ydb_sqlalchemy/sqlalchemy/__init__.py
+++ b/ydb_sqlalchemy/sqlalchemy/__init__.py
@@ -9,23 +9,25 @@
 
 import sqlalchemy as sa
 import ydb
+import ydb_dbapi
 from sqlalchemy import util
 from sqlalchemy.engine import characteristics, reflection
 from sqlalchemy.engine.default import DefaultExecutionContext, StrCompileDialect
 from sqlalchemy.exc import NoSuchTableError
 from sqlalchemy.sql import functions
-
 from sqlalchemy.sql.elements import ClauseList
 
-import ydb_dbapi
+from ydb_sqlalchemy.sqlalchemy.compiler import (
+    YqlCompiler,
+    YqlDDLCompiler,
+    YqlIdentifierPreparer,
+    YqlTypeCompiler,
+)
 from ydb_sqlalchemy.sqlalchemy.dbapi_adapter import AdaptedAsyncConnection
 from ydb_sqlalchemy.sqlalchemy.dml import Upsert
 
-from ydb_sqlalchemy.sqlalchemy.compiler import YqlCompiler, YqlDDLCompiler, YqlIdentifierPreparer, YqlTypeCompiler
-
 from . import types
 
-
 OLD_SA = sa.__version__ < "2."
 
 
diff --git a/ydb_sqlalchemy/sqlalchemy/compiler/__init__.py b/ydb_sqlalchemy/sqlalchemy/compiler/__init__.py
index 31affdd..7e7316e 100644
--- a/ydb_sqlalchemy/sqlalchemy/compiler/__init__.py
+++ b/ydb_sqlalchemy/sqlalchemy/compiler/__init__.py
@@ -3,14 +3,18 @@
 sa_version = sa.__version__
 
 if sa_version.startswith("2."):
-    from .sa20 import YqlCompiler
-    from .sa20 import YqlDDLCompiler
-    from .sa20 import YqlTypeCompiler
-    from .sa20 import YqlIdentifierPreparer
+    from .sa20 import (
+        YqlCompiler,
+        YqlDDLCompiler,
+        YqlIdentifierPreparer,
+        YqlTypeCompiler,
+    )
 elif sa_version.startswith("1.4."):
-    from .sa14 import YqlCompiler
-    from .sa14 import YqlDDLCompiler
-    from .sa14 import YqlTypeCompiler
-    from .sa14 import YqlIdentifierPreparer
+    from .sa14 import (
+        YqlCompiler,
+        YqlDDLCompiler,
+        YqlIdentifierPreparer,
+        YqlTypeCompiler,
+    )
 else:
     raise RuntimeError("Unsupported SQLAlchemy version.")
diff --git a/ydb_sqlalchemy/sqlalchemy/compiler/base.py b/ydb_sqlalchemy/sqlalchemy/compiler/base.py
index c522765..e0d7088 100644
--- a/ydb_sqlalchemy/sqlalchemy/compiler/base.py
+++ b/ydb_sqlalchemy/sqlalchemy/compiler/base.py
@@ -1,8 +1,8 @@
 import collections
+from typing import Any, Dict, List, Mapping, Optional, Sequence, Tuple, Type, Union
+
 import sqlalchemy as sa
 import ydb
-from ydb_dbapi import NotSupportedError
-
 from sqlalchemy.exc import CompileError
 from sqlalchemy.sql import ddl
 from sqlalchemy.sql.compiler import (
@@ -12,22 +12,10 @@
     StrSQLTypeCompiler,
     selectable,
 )
-from typing import (
-    Any,
-    Dict,
-    List,
-    Mapping,
-    Sequence,
-    Optional,
-    Tuple,
-    Type,
-    Union,
-)
-
+from ydb_dbapi import NotSupportedError
 
 from .. import types
 
-
 OLD_SA = sa.__version__ < "2."
 if OLD_SA:
     from sqlalchemy import bindparam as _bindparam
diff --git a/ydb_sqlalchemy/sqlalchemy/compiler/sa14.py b/ydb_sqlalchemy/sqlalchemy/compiler/sa14.py
index 598fc29..a6ad1d4 100644
--- a/ydb_sqlalchemy/sqlalchemy/compiler/sa14.py
+++ b/ydb_sqlalchemy/sqlalchemy/compiler/sa14.py
@@ -1,4 +1,5 @@
 from typing import Union
+
 import sqlalchemy as sa
 import ydb
 
diff --git a/ydb_sqlalchemy/sqlalchemy/compiler/sa20.py b/ydb_sqlalchemy/sqlalchemy/compiler/sa20.py
index 702d7aa..a838ad7 100644
--- a/ydb_sqlalchemy/sqlalchemy/compiler/sa20.py
+++ b/ydb_sqlalchemy/sqlalchemy/compiler/sa20.py
@@ -1,6 +1,7 @@
+from typing import Union
+
 import sqlalchemy as sa
 import ydb
-
 from sqlalchemy.exc import CompileError
 from sqlalchemy.sql import literal_column
 from sqlalchemy.util.compat import inspect_getfullargspec
@@ -11,7 +12,6 @@
     BaseYqlIdentifierPreparer,
     BaseYqlTypeCompiler,
 )
-from typing import Union
 
 
 class YqlTypeCompiler(BaseYqlTypeCompiler):
@@ -89,4 +89,17 @@ def visit_upsert(self, insert_stmt, visited_bindparam=None, **kw):
 
 
 class YqlDDLCompiler(BaseYqlDDLCompiler):
-    ...
+    def visit_foreign_key_constraint(self, constraint, **kwargs):
+        return None
+
+    def visit_primary_key_constraint(self, constraint, **kwargs):
+        if len(constraint) == 0:
+            return ""
+        text = ""
+        text += "PRIMARY KEY "
+        text += "(%s)" % ", ".join(
+            self.preparer.quote(c.name)
+            for c in (constraint.columns_autoinc_first if constraint._implicit_generated else constraint.columns)
+        )
+        text += self.define_constraint_deferrability(constraint)
+        return text
diff --git a/ydb_sqlalchemy/sqlalchemy/dbapi_adapter.py b/ydb_sqlalchemy/sqlalchemy/dbapi_adapter.py
index 66f72ae..6972954 100644
--- a/ydb_sqlalchemy/sqlalchemy/dbapi_adapter.py
+++ b/ydb_sqlalchemy/sqlalchemy/dbapi_adapter.py
@@ -1,8 +1,7 @@
+import ydb
 from sqlalchemy.engine.interfaces import AdaptedConnection
-
 from sqlalchemy.util.concurrency import await_only
 from ydb_dbapi import AsyncConnection, AsyncCursor
-import ydb
 
 
 class AdaptedAsyncConnection(AdaptedConnection):