[1.7.x] Adjusted refactoring of vendor checks.

Thanks Shai for the thorough review.

Backport of fb90b7c from master

3 files changed, 6 insertions, 5 deletions

diff --git a/django/db/backends/__init__.py b/django/db/backends/__init__.py
index 1f223ed8a3..3ad1440bda 100644
--- a/django/db/backends/__init__.py
+++ b/django/db/backends/__init__.py
@@ -616,8 +616,6 @@ class BaseDatabaseFeatures(object):
     supports_subqueries_in_group_by = True
     supports_bitwise_or = True
 
-    supports_boolean_type = True
-
     supports_binary_field = True
 
     # Do time/datetime fields have microsecond precision?
@@ -679,6 +677,9 @@ class BaseDatabaseFeatures(object):
     # Can the backend introspect an BinaryField, instead of an TextField?
     can_introspect_binary_field = True
 
+    # Can the backend introspect an BooleanField, instead of an IntegerField?
+    can_introspect_boolean_field = True
+
     # Can the backend introspect an IPAddressField, instead of an CharField?
     can_introspect_ip_address_field = False
 
@@ -737,7 +738,7 @@ class BaseDatabaseFeatures(object):
     # Suffix for backends that don't support "SELECT xxx;" queries.
     bare_select_suffix = ''
 
-    lowercases_column_names = False
+    uppercases_column_names = True
 
     def __init__(self, connection):
         self.connection = connection
diff --git a/django/db/backends/mysql/base.py b/django/db/backends/mysql/base.py
index 3c71c5792c..9172d7069a 100644
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@@ -172,13 +172,13 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     has_select_for_update_nowait = False
     supports_forward_references = False
     supports_long_model_names = False
-    supports_boolean_type = False
     # XXX MySQL DB-API drivers currently fail on binary data on Python 3.
     supports_binary_field = six.PY2
     supports_microsecond_precision = False
     supports_regex_backreferencing = False
     supports_date_lookup_using_string = False
     can_introspect_binary_field = False
+    can_introspect_boolean_field = False
     supports_timezones = False
     requires_explicit_null_ordering_when_grouping = True
     allows_auto_pk_0 = False
diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index 312eb7e40b..f945b26101 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -120,7 +120,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     connection_persists_old_columns = True
     closed_cursor_error_class = InterfaceError
     bare_select_suffix = " FROM DUAL"
-    lowercases_column_names = True
+    uppercases_column_names = False
 
 
 class DatabaseOperations(BaseDatabaseOperations):