Ticket #1373: fix_drop_foreignkey.diff

db/backends/ado_mssql/base.py

@@ -114 +114 @@
 def get_random_function_sql():
     return "RAND()"
 
+def get_foreignkey_drop(table, name):
+    return "ALTER TABLE %s DROP CONSTRAINT %s;" % \
+        (quote_name(table),quote_name(name))
+
 OPERATOR_MAPPING = {
     'exact': '= %s',
     'iexact': 'LIKE %s',

db/backends/postgresql/base.py

@@ -91 +91 @@
 def get_random_function_sql():
     return "RANDOM()"
 
+def get_foreignkey_drop(table, name):
+    return "ALTER TABLE %s DROP CONSTRAINT %s;" % \
+        (quote_name(table),quote_name(name))
+
 # Register these custom typecasts, because Django expects dates/times to be
 # in Python's native (standard-library) datetime/time format, whereas psycopg
 # use mx.DateTime by default.

db/backends/sqlite3/base.py

@@ -110 +110 @@
 def get_random_function_sql():
     return "RANDOM()"
 
+def get_foreignkey_drop(table, name):
+    return ""
+
 def _sqlite_date_trunc(lookup_type, dt):
     try:
         dt = util.typecast_timestamp(dt)

db/backends/mysql/base.py

@@ -130 +130 @@
 def get_random_function_sql():
     return "RAND()"
 
+def get_foreignkey_drop(table, name):
+    return "ALTER TABLE %s DROP FOREIGN KEY %s;" % \
+        (quote_name(table),quote_name(name))
+
 OPERATOR_MAPPING = {
     'exact': '= %s',
     'iexact': 'LIKE %s',

core/management.py

@@ -252 +252 @@
                     col = f.column
                     r_table = klass._meta.db_table
                     r_col = klass._meta.get_field(f.rel.field_name).column
-                    output.append('ALTER TABLE %s DROP CONSTRAINT %s;' % \
-                       (backend.quote_name(table),
-                        backend.quote_name("%s_referencing_%s_%s" % (col, r_table, r_col))))
+                    output.append(backend.get_foreignkey_drop(table,
+                        "%s_referencing_%s_%s" % (col, r_table, r_col)))
                 del references_to_delete[klass]
 
     # Output DROP TABLE statements for many-to-many tables.