From 06315375ce5c6477b7498026177b7e715372a7d1 Mon Sep 17 00:00:00 2001
From: Adrian Holovaty <adrian@holovaty.com>
Date: Mon, 16 Jun 2008 03:15:04 +0000
Subject: [PATCH] Fixed #7420 -- Abstracted some more database options into
 DatabaseFeatures -- supports_usecs, time_field_needs_date,
 interprets_empty_strings_as_nulls and date_field_supports_time_value -- and
 changed various hard-coded 'if DATABASE_BACKEND == oracle' statements to use
 the new options. Thanks to ramiro for the patch

git-svn-id: http://code.djangoproject.com/svn/django/trunk@7643 bcc190cf-cafb-0310-a4f2-bffc1f526a37
---
 django/db/backends/__init__.py       |  9 ++++++++
 django/db/backends/mysql/base.py     |  1 +
 django/db/backends/mysql_old/base.py |  1 +
 django/db/backends/oracle/base.py    |  3 +++
 django/db/models/fields/__init__.py  | 32 ++++++++++++++--------------
 5 files changed, 30 insertions(+), 16 deletions(-)

diff --git a/django/db/backends/__init__.py b/django/db/backends/__init__.py
index b076e290dd..63a6435bdb 100644
--- a/django/db/backends/__init__.py
+++ b/django/db/backends/__init__.py
@@ -52,6 +52,10 @@ class BaseDatabaseFeatures(object):
     uses_custom_query_class = False
     empty_fetchmany_value = []
     update_can_self_select = True
+    supports_usecs = True
+    time_field_needs_date = False
+    interprets_empty_strings_as_nulls = False
+    date_field_supports_time_value = True
 
 class BaseDatabaseOperations(object):
     """
@@ -266,3 +270,8 @@ class BaseDatabaseOperations(object):
         tablespaces.
         """
         return None
+
+    def prep_for_like_query(self, x):
+        """Prepares a value for use in a LIKE query."""
+        from django.utils.encoding import smart_unicode
+        return smart_unicode(x).replace("\\", "\\\\").replace("%", "\%").replace("_", "\_")
diff --git a/django/db/backends/mysql/base.py b/django/db/backends/mysql/base.py
index da57ecbe47..23735a023b 100644
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@@ -64,6 +64,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     inline_fk_references = False
     empty_fetchmany_value = ()
     update_can_self_select = False
+    supports_usecs = False
 
 class DatabaseOperations(BaseDatabaseOperations):
     def date_extract_sql(self, lookup_type, field_name):
diff --git a/django/db/backends/mysql_old/base.py b/django/db/backends/mysql_old/base.py
index 0ae114d176..e57aee6a04 100644
--- a/django/db/backends/mysql_old/base.py
+++ b/django/db/backends/mysql_old/base.py
@@ -68,6 +68,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     inline_fk_references = False
     empty_fetchmany_value = ()
     update_can_self_select = False
+    supports_usecs = False
 
 class DatabaseOperations(BaseDatabaseOperations):
     def date_extract_sql(self, lookup_type, field_name):
diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index 3635acdf2a..a1a9fb1c73 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -31,6 +31,9 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     supports_tablespaces = True
     uses_case_insensitive_names = True
     uses_custom_query_class = True
+    time_field_needs_date = True
+    interprets_empty_strings_as_nulls = True
+    date_field_supports_time_value = False
 
 class DatabaseOperations(BaseDatabaseOperations):
     def autoinc_sql(self, table, column):
diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index 88033756ee..96bb466c7b 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -7,7 +7,7 @@ try:
 except ImportError:
     from django.utils import _decimal as decimal    # for Python 2.3
 
-from django.db import get_creation_module
+from django.db import connection, get_creation_module
 from django.db.models import signals
 from django.db.models.query_utils import QueryWrapper
 from django.dispatch import dispatcher
@@ -33,9 +33,6 @@ HORIZONTAL, VERTICAL = 1, 2
 BLANK_CHOICE_DASH = [("", "---------")]
 BLANK_CHOICE_NONE = [("", "None")]
 
-# prepares a value for use in a LIKE query
-prep_for_like_query = lambda x: smart_unicode(x).replace("\\", "\\\\").replace("%", "\%").replace("_", "\_")
-
 # returns the <ul> class for a given radio_admin value
 get_ul_class = lambda x: 'radiolist%s' % ((x == HORIZONTAL) and ' inline' or '')
 
@@ -97,7 +94,7 @@ class Field(object):
         self.blank, self.null = blank, null
         # Oracle treats the empty string ('') as null, so coerce the null
         # option whenever '' is a possible value.
-        if self.empty_strings_allowed and settings.DATABASE_ENGINE == 'oracle':
+        if self.empty_strings_allowed and connection.features.interprets_empty_strings_as_nulls:
             self.null = True
         self.core, self.rel, self.default = core, rel, default
         self.editable = editable
@@ -235,13 +232,13 @@ class Field(object):
         elif lookup_type in ('range', 'in'):
             return value
         elif lookup_type in ('contains', 'icontains'):
-            return ["%%%s%%" % prep_for_like_query(value)]
+            return ["%%%s%%" % connection.ops.prep_for_like_query(value)]
         elif lookup_type == 'iexact':
-            return [prep_for_like_query(value)]
+            return [connection.ops.prep_for_like_query(value)]
         elif lookup_type in ('startswith', 'istartswith'):
-            return ["%s%%" % prep_for_like_query(value)]
+            return ["%s%%" % connection.ops.prep_for_like_query(value)]
         elif lookup_type in ('endswith', 'iendswith'):
-            return ["%%%s" % prep_for_like_query(value)]
+            return ["%%%s" % connection.ops.prep_for_like_query(value)]
         elif lookup_type == 'isnull':
             return []
         elif lookup_type == 'year':
@@ -252,9 +249,12 @@ class Field(object):
             if settings.DATABASE_ENGINE == 'sqlite3':
                 first = '%s-01-01'
                 second = '%s-12-31 23:59:59.999999'
-            elif settings.DATABASE_ENGINE == 'oracle' and self.get_internal_type() == 'DateField':
+            elif not connection.features.date_field_supports_time_value and self.get_internal_type() == 'DateField':
                 first = '%s-01-01'
                 second = '%s-12-31'
+            elif not connection.features.supports_usecs:
+                first = '%s-01-01 00:00:00'
+                second = '%s-12-31 23:59:59.99'
             else:
                 first = '%s-01-01 00:00:00'
                 second = '%s-12-31 23:59:59.999999'
@@ -271,7 +271,7 @@ class Field(object):
             if callable(self.default):
                 return self.default()
             return force_unicode(self.default, strings_only=True)
-        if not self.empty_strings_allowed or (self.null and settings.DATABASE_ENGINE != 'oracle'):
+        if not self.empty_strings_allowed or (self.null and not connection.features.interprets_empty_strings_as_nulls):
             return None
         return ""
 
@@ -629,7 +629,7 @@ class DateTimeField(DateField):
         if value is not None:
             # MySQL will throw a warning if microseconds are given, because it
             # doesn't support microseconds.
-            if settings.DATABASE_ENGINE == 'mysql' and hasattr(value, 'microsecond'):
+            if not connection.features.supports_usecs and hasattr(value, 'microsecond'):
                 value = value.replace(microsecond=0)
             value = smart_unicode(value)
         return Field.get_db_prep_save(self, value)
@@ -863,7 +863,7 @@ class FilePathField(Field):
         self.path, self.match, self.recursive = path, match, recursive
         kwargs['max_length'] = kwargs.get('max_length', 100)
         Field.__init__(self, verbose_name, name, **kwargs)
-    
+
     def formfield(self, **kwargs):
         defaults = {
             'path': self.path,
@@ -1071,7 +1071,7 @@ class TimeField(Field):
         return "TimeField"
 
     def get_db_prep_lookup(self, lookup_type, value):
-        if settings.DATABASE_ENGINE == 'oracle':
+        if connection.features.time_field_needs_date:
             # Oracle requires a date in order to parse.
             def prep(value):
                 if isinstance(value, datetime.time):
@@ -1098,9 +1098,9 @@ class TimeField(Field):
         if value is not None:
             # MySQL will throw a warning if microseconds are given, because it
             # doesn't support microseconds.
-            if settings.DATABASE_ENGINE == 'mysql' and hasattr(value, 'microsecond'):
+            if not connection.features.supports_usecs and hasattr(value, 'microsecond'):
                 value = value.replace(microsecond=0)
-            if settings.DATABASE_ENGINE == 'oracle':
+            if connection.features.time_field_needs_date:
                 # cx_Oracle expects a datetime.datetime to persist into TIMESTAMP field.
                 if isinstance(value, datetime.time):
                     value = datetime.datetime(1900, 1, 1, value.hour, value.minute,