Refactored get_deferrable_sql() to DatabaseOperations.deferrable_sql(). Refs #5106

git-svn-id: http://code.djangoproject.com/svn/django/trunk@5955 bcc190cf-cafb-0310-a4f2-bffc1f526a37

10 files changed, 25 insertions, 28 deletions

diff --git a/django/core/management/sql.py b/django/core/management/sql.py
index 90599b9a4d..766d05129f 100644
--- a/django/core/management/sql.py
+++ b/django/core/management/sql.py
@@ -243,7 +243,7 @@ def sql_model_create(model, style, known_models=set()):
                 field_output.append(style.SQL_KEYWORD('REFERENCES') + ' ' + \
                     style.SQL_TABLE(backend.quote_name(f.rel.to._meta.db_table)) + ' (' + \
                     style.SQL_FIELD(backend.quote_name(f.rel.to._meta.get_field(f.rel.field_name).column)) + ')' +
-                    backend.get_deferrable_sql()
+                    connection.ops.deferrable_sql()
                 )
             else:
                 # We haven't yet created the table to which this field
@@ -280,7 +280,7 @@ def sql_for_pending_references(model, style, pending_references):
     """
     Returns any ALTER TABLE statements to add constraints after the fact.
     """
-    from django.db import backend
+    from django.db import backend, connection
     from django.db.backends.util import truncate_name
 
     final_output = []
@@ -299,12 +299,12 @@ def sql_for_pending_references(model, style, pending_references):
                 final_output.append(style.SQL_KEYWORD('ALTER TABLE') + ' %s ADD CONSTRAINT %s FOREIGN KEY (%s) REFERENCES %s (%s)%s;' % \
                     (backend.quote_name(r_table), truncate_name(r_name, backend.get_max_name_length()),
                     backend.quote_name(r_col), backend.quote_name(table), backend.quote_name(col),
-                    backend.get_deferrable_sql()))
+                    connection.ops.deferrable_sql()))
             del pending_references[model]
     return final_output
 
 def many_to_many_sql_for_model(model, style):
-    from django.db import backend, models
+    from django.db import backend, connection, models
     from django.contrib.contenttypes import generic
 
     opts = model._meta
@@ -329,14 +329,14 @@ def many_to_many_sql_for_model(model, style):
                 style.SQL_KEYWORD('NOT NULL REFERENCES'),
                 style.SQL_TABLE(backend.quote_name(opts.db_table)),
                 style.SQL_FIELD(backend.quote_name(opts.pk.column)),
-                backend.get_deferrable_sql()))
+                connection.ops.deferrable_sql()))
             table_output.append('    %s %s %s %s (%s)%s,' % \
                 (style.SQL_FIELD(backend.quote_name(f.m2m_reverse_name())),
                 style.SQL_COLTYPE(models.ForeignKey(f.rel.to).db_type()),
                 style.SQL_KEYWORD('NOT NULL REFERENCES'),
                 style.SQL_TABLE(backend.quote_name(f.rel.to._meta.db_table)),
                 style.SQL_FIELD(backend.quote_name(f.rel.to._meta.pk.column)),
-                backend.get_deferrable_sql()))
+                connection.ops.deferrable_sql()))
             table_output.append('    %s (%s, %s)%s' % \
                 (style.SQL_KEYWORD('UNIQUE'),
                 style.SQL_FIELD(backend.quote_name(f.m2m_column_name())),
diff --git a/django/db/backends/__init__.py b/django/db/backends/__init__.py
index 41295a15b7..ea75dcf840 100644
--- a/django/db/backends/__init__.py
+++ b/django/db/backends/__init__.py
@@ -78,3 +78,10 @@ class BaseDatabaseOperations(object):
         method should return None if no casting is necessary.
         """
         return None
+
+    def deferrable_sql(self):
+        """
+        Returns the SQL necessary to make a constraint "initially deferred"
+        during a CREATE TABLE statement.
+        """
+        return ''
diff --git a/django/db/backends/ado_mssql/base.py b/django/db/backends/ado_mssql/base.py
index 9d72433208..f97822ebea 100644
--- a/django/db/backends/ado_mssql/base.py
+++ b/django/db/backends/ado_mssql/base.py
@@ -60,6 +60,9 @@ class DatabaseOperations(BaseDatabaseOperations):
         if lookup_type == 'day':
             return "Convert(datetime, Convert(varchar(12), %s))" % field_name
 
+    def deferrable_sql(self):
+        return " DEFERRABLE INITIALLY DEFERRED"
+
 class DatabaseWrapper(BaseDatabaseWrapper):
     ops = DatabaseOperations()
 
@@ -107,9 +110,6 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "RAND()"
 
-def get_deferrable_sql():
-    return " DEFERRABLE INITIALLY DEFERRED"
-
 def get_fulltext_search_sql(field_name):
     raise NotImplementedError
 
diff --git a/django/db/backends/dummy/base.py b/django/db/backends/dummy/base.py
index 95650ffbf7..21a0bb6a5f 100644
--- a/django/db/backends/dummy/base.py
+++ b/django/db/backends/dummy/base.py
@@ -46,7 +46,6 @@ dictfetchall = complain
 get_last_insert_id = complain
 get_limit_offset_sql = complain
 get_random_function_sql = complain
-get_deferrable_sql = complain
 get_fulltext_search_sql = complain
 get_drop_foreignkey_sql = complain
 get_pk_default_value = complain
diff --git a/django/db/backends/mysql/base.py b/django/db/backends/mysql/base.py
index 56976b77cc..d00829f502 100644
--- a/django/db/backends/mysql/base.py
+++ b/django/db/backends/mysql/base.py
@@ -161,9 +161,6 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "RAND()"
 
-def get_deferrable_sql():
-    return ""
-
 def get_fulltext_search_sql(field_name):
     return 'MATCH (%s) AGAINST (%%s IN BOOLEAN MODE)' % field_name
 
diff --git a/django/db/backends/mysql_old/base.py b/django/db/backends/mysql_old/base.py
index c7eea74b6d..a3dfcf0e76 100644
--- a/django/db/backends/mysql_old/base.py
+++ b/django/db/backends/mysql_old/base.py
@@ -180,9 +180,6 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "RAND()"
 
-def get_deferrable_sql():
-    return ""
-
 def get_fulltext_search_sql(field_name):
     return 'MATCH (%s) AGAINST (%%s IN BOOLEAN MODE)' % field_name
 
diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index 8847368cee..6198ee8030 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -54,6 +54,9 @@ class DatabaseOperations(BaseDatabaseOperations):
     def datetime_cast_sql(self):
         return "TO_TIMESTAMP(%s, 'YYYY-MM-DD HH24:MI:SS.FF')"
 
+    def deferrable_sql(self):
+        return " DEFERRABLE INITIALLY DEFERRED"
+
 class DatabaseWrapper(BaseDatabaseWrapper):
     ops = DatabaseOperations()
 
@@ -183,9 +186,6 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "DBMS_RANDOM.RANDOM"
 
-def get_deferrable_sql():
-    return " DEFERRABLE INITIALLY DEFERRED"
-
 def get_fulltext_search_sql(field_name):
     raise NotImplementedError
 
diff --git a/django/db/backends/postgresql/base.py b/django/db/backends/postgresql/base.py
index 8c06bb494e..4fec530b5b 100644
--- a/django/db/backends/postgresql/base.py
+++ b/django/db/backends/postgresql/base.py
@@ -66,6 +66,9 @@ class DatabaseOperations(BaseDatabaseOperations):
         # http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
         return "DATE_TRUNC('%s', %s)" % (lookup_type, field_name)
 
+    def deferrable_sql(self):
+        return " DEFERRABLE INITIALLY DEFERRED"
+
 class DatabaseWrapper(BaseDatabaseWrapper):
     ops = DatabaseOperations()
 
@@ -137,9 +140,6 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "RANDOM()"
 
-def get_deferrable_sql():
-    return " DEFERRABLE INITIALLY DEFERRED"
-
 def get_fulltext_search_sql(field_name):
     raise NotImplementedError
 
diff --git a/django/db/backends/postgresql_psycopg2/base.py b/django/db/backends/postgresql_psycopg2/base.py
index 6a471a4f04..56cb53e3bc 100644
--- a/django/db/backends/postgresql_psycopg2/base.py
+++ b/django/db/backends/postgresql_psycopg2/base.py
@@ -28,6 +28,9 @@ class DatabaseOperations(BaseDatabaseOperations):
         # http://www.postgresql.org/docs/8.0/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC
         return "DATE_TRUNC('%s', %s)" % (lookup_type, field_name)
 
+    def deferrable_sql(self):
+        return " DEFERRABLE INITIALLY DEFERRED"
+
 class DatabaseWrapper(BaseDatabaseWrapper):
     ops = DatabaseOperations()
 
@@ -91,9 +94,6 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "RANDOM()"
 
-def get_deferrable_sql():
-    return " DEFERRABLE INITIALLY DEFERRED"
-
 def get_fulltext_search_sql(field_name):
     raise NotImplementedError
 
diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index 3e99ac72c7..88df473f52 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -124,9 +124,6 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "RANDOM()"
 
-def get_deferrable_sql():
-    return ""
-
 def get_fulltext_search_sql(field_name):
     raise NotImplementedError