SNOW-227101: fix to datetime columns being created without timezone (TIMESTAMP_NTZ).

Commit 28e8031 introduced a bug where all sqlalchemy.DateTime(timezone=True) columns were created as DATETIME in Snowflake which is an alias to TIMESTAMP_NTZ.
This commit reverts datetime logic back so if the timezone is defined in datetime column it will create TIMESTAMP_TZ and TIMESTAMP_NTZ otherwise.

Author: Nazarii

base.py

@@ -419,10 +419,10 @@ def visit_BLOB(self, type_, **kw):
         return "BINARY"
 
     def visit_datetime(self, type_, **kw):
-        return "datetime"
+        return self.visit_TIMESTAMP(type_, **kw)
 
     def visit_DATETIME(self, type_, **kw):
-        return "DATETIME"
+        return self.visit_TIMESTAMP(type_, **kw)
 
     def visit_TIMESTAMP_NTZ(self, type_, **kw):
         return "TIMESTAMP_NTZ"
@@ -434,8 +434,14 @@ def visit_TIMESTAMP_LTZ(self, type_, **kw):
         return "TIMESTAMP_LTZ"
 
     def visit_TIMESTAMP(self, type_, **kw):
-        return "TIMESTAMP"
-
+        is_local = kw.get('is_local', False)
+        timezone = kw.get('timezone', type_.timezone)
+        return "TIMESTAMP %s%s" % (
+            (timezone and "WITH" or "WITHOUT") + (
+                    is_local and " LOCAL" or "") + " TIME ZONE",
+            "(%d)" % type_.precision if getattr(type_, 'precision',
+                                               None) is not None else ""
+        )
 
 construct_arguments = [
     (Table, {

test/test_timestamp.py

@@ -9,7 +9,7 @@
 import pytz
 from parameters import CONNECTION_PARAMETERS
 from snowflake.sqlalchemy import TIMESTAMP_LTZ, TIMESTAMP_NTZ, TIMESTAMP_TZ
-from sqlalchemy import Column, Integer, MetaData, Table
+from sqlalchemy import Column, Integer, MetaData, Table, DateTime
 from sqlalchemy.sql import select
 
 PST_TZ = "America/Los_Angeles"
@@ -33,7 +33,10 @@ def test_create_table_timestamp_datatypes(engine_testaccount):
         Column('id', Integer, primary_key=True),
         Column('tsntz', TIMESTAMP_NTZ),
         Column('tsltz', TIMESTAMP_LTZ),
-        Column('tstz', TIMESTAMP_TZ))
+        Column('tstz', TIMESTAMP_TZ),
+        Column('dttz', DateTime(timezone=True)),
+        Column('dtntz', DateTime(timezone=False))
+    )
     metadata.create_all(engine_testaccount)
     try:
         assert test_timestamp is not None
@@ -53,7 +56,10 @@ def test_inspect_timestamp_datatypes(engine_testaccount):
         Column('id', Integer, primary_key=True),
         Column('tsntz', TIMESTAMP_NTZ),
         Column('tsltz', TIMESTAMP_LTZ),
-        Column('tstz', TIMESTAMP_TZ))
+        Column('tstz', TIMESTAMP_TZ),
+        Column('dttz', DateTime(timezone=True)),
+        Column('dtntz', DateTime(timezone=False)),
+    )
     metadata.create_all(engine_testaccount)
     try:
         current_utctime = datetime.utcnow()
@@ -70,6 +76,8 @@ def test_inspect_timestamp_datatypes(engine_testaccount):
             tsntz=current_utctime,
             tsltz=current_localtime,
             tstz=current_localtime_with_other_tz,
+            dttz=current_localtime_with_other_tz,
+            dtntz=current_utctime,
         )
         results = engine_testaccount.execute(ins)
         results.close()
@@ -84,5 +92,7 @@ def test_inspect_timestamp_datatypes(engine_testaccount):
         assert rows[1] == current_utctime
         assert rows[2] == current_localtime
         assert rows[3] == current_localtime_with_other_tz
+        assert rows[4] == current_localtime_with_other_tz
+        assert rows[5] == current_utctime
     finally:
         test_timestamp.drop(engine_testaccount)