Make sure we only create the minimum number of table indexes for MySQL.

This patch simplifies a bunch of code for all backends and removes some
duplicate index creation for MySQL, in particular (versions 4.x and later).
Patch from Nis Jørgensen.

Fixed #5671, #5680, #7170, #7186.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@7790 bcc190cf-cafb-0310-a4f2-bffc1f526a37

AUTHORS

@@ -192,6 +192,7 @@ answer newbie questions, and generally made Django that much better:
     james_027@yahoo.com
     jcrasta@gmail.com
     Zak Johnson <zakj@nox.cx>
+    Nis Jørgensen <nis@superlativ.dk>
     Michael Josephson <http://www.sdjournal.com/>
     jpellerin@gmail.com
     junzhang.jn@gmail.com

django/core/management/commands/createcachetable.py

@@ -21,10 +21,10 @@ class Command(LabelCommand):
         for f in fields:
             field_output = [qn(f.name), f.db_type()]
             field_output.append("%sNULL" % (not f.null and "NOT " or ""))
-            if f.unique:
-                field_output.append("UNIQUE")
             if f.primary_key:
                 field_output.append("PRIMARY KEY")
+            elif f.unique:
+                field_output.append("UNIQUE")
             if f.db_index:
                 unique = f.unique and "UNIQUE " or ""
                 index_output.append("CREATE %sINDEX %s_%s ON %s (%s);" % \

django/core/management/sql.py

@@ -268,11 +268,11 @@ def sql_model_create(model, style, known_models=set()):
         field_output = [style.SQL_FIELD(qn(f.column)),
             style.SQL_COLTYPE(col_type)]
         field_output.append(style.SQL_KEYWORD('%sNULL' % (not f.null and 'NOT ' or '')))
-        if f.unique and (not f.primary_key or connection.features.allows_unique_and_pk):
-            field_output.append(style.SQL_KEYWORD('UNIQUE'))
         if f.primary_key:
             field_output.append(style.SQL_KEYWORD('PRIMARY KEY'))
-        if tablespace and connection.features.supports_tablespaces and (f.unique or f.primary_key) and connection.features.autoindexes_primary_keys:
+        elif f.unique:
+            field_output.append(style.SQL_KEYWORD('UNIQUE'))
+        if tablespace and connection.features.supports_tablespaces and f.unique:
             # We must specify the index tablespace inline, because we
             # won't be generating a CREATE INDEX statement for this field.
             field_output.append(connection.ops.tablespace_sql(tablespace, inline=True))
@@ -355,7 +355,7 @@ def many_to_many_sql_for_model(model, style):
     for f in opts.local_many_to_many:
         if not isinstance(f.rel, generic.GenericRel):
             tablespace = f.db_tablespace or opts.db_tablespace
-            if tablespace and connection.features.supports_tablespaces and connection.features.autoindexes_primary_keys:
+            if tablespace and connection.features.supports_tablespaces: 
                 tablespace_sql = ' ' + connection.ops.tablespace_sql(tablespace, inline=True)
             else:
                 tablespace_sql = ''
@@ -460,15 +460,14 @@ def sql_indexes_for_model(model, style):
 
     qn = connection.ops.quote_name
     for f in model._meta.local_fields:
-        if f.db_index and not ((f.primary_key or f.unique) and connection.features.autoindexes_primary_keys):
+        if f.db_index and not f.unique:
-            unique = f.unique and 'UNIQUE ' or ''
             tablespace = f.db_tablespace or model._meta.db_tablespace
             if tablespace and connection.features.supports_tablespaces:
                 tablespace_sql = ' ' + connection.ops.tablespace_sql(tablespace)
             else:
                 tablespace_sql = ''
             output.append(
-                style.SQL_KEYWORD('CREATE %sINDEX' % unique) + ' ' + \
+                style.SQL_KEYWORD('CREATE INDEX') + ' ' + \
                 style.SQL_TABLE(qn('%s_%s' % (model._meta.db_table, f.column))) + ' ' + \
                 style.SQL_KEYWORD('ON') + ' ' + \
                 style.SQL_TABLE(qn(model._meta.db_table)) + ' ' + \

django/db/backends/__init__.py

@@ -41,8 +41,6 @@ class BaseDatabaseWrapper(local):
 
 class BaseDatabaseFeatures(object):
     allows_group_by_ordinal = True
-    allows_unique_and_pk = True
-    autoindexes_primary_keys = True
     inline_fk_references = True
     needs_datetime_string_cast = True
     supports_constraints = True

django/db/backends/mysql/base.py

@@ -60,7 +60,6 @@ server_version_re = re.compile(r'(\d{1,2})\.(\d{1,2})\.(\d{1,2})')
 # TRADITIONAL will automatically cause most warnings to be treated as errors.
 
 class DatabaseFeatures(BaseDatabaseFeatures):
-    autoindexes_primary_keys = False
     inline_fk_references = False
     empty_fetchmany_value = ()
     update_can_self_select = False

django/db/backends/mysql_old/base.py

@@ -64,7 +64,6 @@ class MysqlDebugWrapper:
             return getattr(self.cursor, attr)
 
 class DatabaseFeatures(BaseDatabaseFeatures):
-    autoindexes_primary_keys = False
     inline_fk_references = False
     empty_fetchmany_value = ()
     update_can_self_select = False

django/db/backends/oracle/base.py

@@ -24,7 +24,6 @@ IntegrityError = Database.IntegrityError
 
 class DatabaseFeatures(BaseDatabaseFeatures):
     allows_group_by_ordinal = False
-    allows_unique_and_pk = False        # Suppress UNIQUE/PK for Oracle (ORA-02259)
     empty_fetchmany_value = ()
     needs_datetime_string_cast = False
     supports_tablespaces = True

django/db/models/fields/__init__.py

@@ -91,7 +91,7 @@ class Field(object):
         self.name = name
         self.verbose_name = verbose_name
         self.primary_key = primary_key
-        self.max_length, self.unique = max_length, unique
+        self.max_length, self._unique = max_length, unique
         self.blank, self.null = blank, null
         # Oracle treats the empty string ('') as null, so coerce the null
         # option whenever '' is a possible value.
@@ -168,6 +168,10 @@ class Field(object):
         except KeyError:
             return None
 
+    def unique(self):
+        return self._unique or self.primary_key
+    unique = property(unique)
+
     def validate_full(self, field_data, all_data):
         """
         Returns a list of errors for this field. This is the main interface,