From 77239f46bedd1dac48a7f0a60ac20cb4f9784330 Mon Sep 17 00:00:00 2001
From: fabianmenges <fabianmenges@users.noreply.github.com>
Date: Sat, 3 Feb 2018 23:03:02 -0500
Subject: [PATCH] =?UTF-8?q?[BugFix]:=20Creating=20a=20PostgresBaseEngineSp?=
 =?UTF-8?q?ec=20so=20changes=20to=20the=20Postgre=E2=80=A6=20(#4224)?=
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* [BugFix]: Creating a PostgresBaseEngineSpec so changes to the PostgresEngineSpec don't affect every subclass

* Empty engine for abstract Engine
---
 superset/db_engine_specs.py | 75 ++++++++++++++++++-------------------
 1 file changed, 37 insertions(+), 38 deletions(-)

diff --git a/superset/db_engine_specs.py b/superset/db_engine_specs.py
index d26f633bbd266..efd37babfc7e9 100644
--- a/superset/db_engine_specs.py
+++ b/superset/db_engine_specs.py
@@ -280,8 +280,10 @@ def get_configuration_for_impersonation(cls, uri, impersonate_user, username):
         return {}
 
 
-class PostgresEngineSpec(BaseEngineSpec):
-    engine = 'postgresql'
+class PostgresBaseEngineSpec(BaseEngineSpec):
+    """ Abstract class for Postgres 'like' databases """
+
+    engine = ''
 
     time_grains = (
         Grain('Time Column', _('Time Column'), '{col}'),
@@ -311,6 +313,10 @@ def epoch_to_dttm(cls):
     def convert_dttm(cls, target_type, dttm):
         return "'{}'".format(dttm.strftime('%Y-%m-%d %H:%M:%S'))
 
+
+class PostgresEngineSpec(PostgresBaseEngineSpec):
+    engine = 'postgresql'
+
     @classmethod
     def get_table_names(cls, schema, inspector):
         """Need to consider foreign tables for PostgreSQL"""
@@ -319,6 +325,35 @@ def get_table_names(cls, schema, inspector):
         return sorted(tables)
 
 
+class VerticaEngineSpec(PostgresBaseEngineSpec):
+    engine = 'vertica'
+
+
+class RedshiftEngineSpec(PostgresBaseEngineSpec):
+    engine = 'redshift'
+
+
+class OracleEngineSpec(PostgresBaseEngineSpec):
+    engine = 'oracle'
+
+    time_grains = (
+        Grain('Time Column', _('Time Column'), '{col}'),
+        Grain('minute', _('minute'), "TRUNC(TO_DATE({col}), 'MI')"),
+        Grain('hour', _('hour'), "TRUNC(TO_DATE({col}), 'HH')"),
+        Grain('day', _('day'), "TRUNC(TO_DATE({col}), 'DDD')"),
+        Grain('week', _('week'), "TRUNC(TO_DATE({col}), 'WW')"),
+        Grain('month', _('month'), "TRUNC(TO_DATE({col}), 'MONTH')"),
+        Grain('quarter', _('quarter'), "TRUNC(TO_DATE({col}), 'Q')"),
+        Grain('year', _('year'), "TRUNC(TO_DATE({col}), 'YEAR')"),
+    )
+
+    @classmethod
+    def convert_dttm(cls, target_type, dttm):
+        return (
+            """TO_TIMESTAMP('{}', 'YYYY-MM-DD"T"HH24:MI:SS.ff6')"""
+        ).format(dttm.isoformat())
+
+
 class Db2EngineSpec(BaseEngineSpec):
     engine = 'ibm_db_sa'
     time_grains = (
@@ -1046,42 +1081,6 @@ def convert_dttm(cls, target_type, dttm):
         return "CONVERT(DATETIME, '{}', 126)".format(dttm.isoformat())
 
 
-class RedshiftEngineSpec(PostgresEngineSpec):
-    engine = 'redshift'
-
-
-class OracleEngineSpec(PostgresEngineSpec):
-    engine = 'oracle'
-
-    time_grains = (
-        Grain('Time Column', _('Time Column'), '{col}'),
-        Grain('minute', _('minute'),
-              "TRUNC(TO_DATE({col}), 'MI')"),
-        Grain('hour', _('hour'),
-              "TRUNC(TO_DATE({col}), 'HH')"),
-        Grain('day', _('day'),
-              "TRUNC(TO_DATE({col}), 'DDD')"),
-        Grain('week', _('week'),
-              "TRUNC(TO_DATE({col}), 'WW')"),
-        Grain('month', _('month'),
-              "TRUNC(TO_DATE({col}), 'MONTH')"),
-        Grain('quarter', _('quarter'),
-              "TRUNC(TO_DATE({col}), 'Q')"),
-        Grain('year', _('year'),
-              "TRUNC(TO_DATE({col}), 'YEAR')"),
-    )
-
-    @classmethod
-    def convert_dttm(cls, target_type, dttm):
-        return (
-            """TO_TIMESTAMP('{}', 'YYYY-MM-DD"T"HH24:MI:SS.ff6')"""
-        ).format(dttm.isoformat())
-
-
-class VerticaEngineSpec(PostgresEngineSpec):
-    engine = 'vertica'
-
-
 class AthenaEngineSpec(BaseEngineSpec):
     engine = 'awsathena'