magic-removal: Fixed #1373 -- Factored out database-specific 'DROP CONSTRAINT' syntax, to get sqlreset/sqlclear working with MySQL. Thanks, njharman

git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@2732 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/core/management.py

@@ -290,7 +290,7 @@ def get_sql_delete(app):
                     output.append('%s %s %s %s;' % \
                         (style.SQL_KEYWORD('ALTER TABLE'),
                         style.SQL_TABLE(backend.quote_name(table)),
-                        style.SQL_KEYWORD('DROP CONSTRAINT'),
+                        style.SQL_KEYWORD(backend.get_drop_foreignkey_sql()),
                         style.SQL_FIELD(backend.quote_name("%s_referencing_%s_%s" % (col, r_table, r_col)))))
                 del references_to_delete[klass]
 

django/db/backends/ado_mssql/base.py

@@ -121,6 +121,9 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "RAND()"
 
+def get_drop_foreignkey_sql():
+    return "DROP CONSTRAINT"
+
 OPERATOR_MAPPING = {
     'exact': '= %s',
     'iexact': 'LIKE %s',

django/db/backends/dummy/base.py

@@ -33,4 +33,5 @@ get_date_extract_sql = complain
 get_date_trunc_sql = complain
 get_limit_offset_sql = complain
 get_random_function_sql = complain
+get_drop_foreignkey_sql = complain
 OPERATOR_MAPPING = {}

django/db/backends/mysql/base.py

@@ -146,6 +146,9 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "RAND()"
 
+def get_drop_foreignkey_sql():
+    return "DROP FOREIGN KEY"
+
 OPERATOR_MAPPING = {
     'exact': '= %s',
     'iexact': 'LIKE %s',

django/db/backends/postgresql/base.py

@@ -98,6 +98,9 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "RANDOM()"
 
+def get_drop_foreignkey_sql():
+    return "DROP CONSTRAINT"
+
 # 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.

django/db/backends/sqlite3/base.py

@@ -116,6 +116,9 @@ def get_limit_offset_sql(limit, offset=None):
 def get_random_function_sql():
     return "RANDOM()"
 
+def get_drop_foreignkey_sql():
+    return ""
+
 def _sqlite_date_trunc(lookup_type, dt):
     try:
         dt = util.typecast_timestamp(dt)