Merge pull request #817 from rybaktomasz/ticket_5568

Fixes #5568 -- DROP INDEX subcommand 

4 files changed, 102 insertions, 0 deletions

diff --git a/django/core/management/commands/sqldropindexes.py b/django/core/management/commands/sqldropindexes.py
new file mode 100644
index 0000000000..fce77211fb
--- /dev/null
+++ b/django/core/management/commands/sqldropindexes.py
@@ -0,0 +1,23 @@
+from __future__ import unicode_literals
+
+from optparse import make_option
+
+from django.core.management.base import AppCommand
+from django.core.management.sql import sql_destroy_indexes
+from django.db import connections, DEFAULT_DB_ALIAS
+
+class Command(AppCommand):
+    help = "Prints the DROP INDEX SQL statements for the given model module name(s)."
+
+    option_list = AppCommand.option_list + (
+        make_option('--database', action='store', dest='database',
+            default=DEFAULT_DB_ALIAS, help='Nominates a database to print the '
+                'SQL for.  Defaults to the "default" database.'),
+
+    )
+
+    output_transaction = True
+
+    def handle_app(self, app, **options):
+        return '\n'.join(sql_destroy_indexes(app, self.style, connections[options.get('database')]))
+
diff --git a/django/core/management/sql.py b/django/core/management/sql.py
index 66df43e971..ac60ed470c 100644
--- a/django/core/management/sql.py
+++ b/django/core/management/sql.py
@@ -137,6 +137,13 @@ def sql_indexes(app, style, connection):
         output.extend(connection.creation.sql_indexes_for_model(model, style))
     return output
 
+def sql_destroy_indexes(app, style, connection):
+    "Returns a list of the DROP INDEX SQL statements for all models in the given app."
+    output = []
+    for model in models.get_models(app):
+        output.extend(connection.creation.sql_destroy_indexes_for_model(model, style))
+    return output
+
 
 def sql_all(app, style, connection):
     "Returns a list of CREATE TABLE SQL, initial-data inserts, and CREATE INDEX SQL for the given module."
diff --git a/django/db/backends/creation.py b/django/db/backends/creation.py
index 89ff1170dc..77c9e6c9e6 100644
--- a/django/db/backends/creation.py
+++ b/django/db/backends/creation.py
@@ -259,6 +259,52 @@ class BaseDatabaseCreation(object):
         del references_to_delete[model]
         return output
 
+    def sql_destroy_indexes_for_model(self, model, style):
+        """
+        Returns the DROP INDEX SQL statements for a single model.
+        """
+        if not model._meta.managed or model._meta.proxy or model._meta.swapped:
+            return []
+        output = []
+        for f in model._meta.local_fields:
+            output.extend(self.sql_destroy_indexes_for_field(model, f, style))
+        for fs in model._meta.index_together:
+            fields = [model._meta.get_field_by_name(f)[0] for f in fs]
+            output.extend(self.sql_destroy_indexes_for_fields(model, fields, style))
+        return output
+
+    def sql_destroy_indexes_for_field(self, model, f, style):
+        """
+        Return the DROP INDEX SQL statements for a single model field.
+        """
+        if f.db_index and not f.unique:
+            return self.sql_destroy_indexes_for_fields(model, [f], style)
+        else:
+            return []
+
+    def sql_destroy_indexes_for_fields(self, model, fields, style):
+        if len(fields) == 1 and fields[0].db_tablespace:
+            tablespace_sql = self.connection.ops.tablespace_sql(fields[0].db_tablespace)
+        elif model._meta.db_tablespace:
+            tablespace_sql = self.connection.ops.tablespace_sql(model._meta.db_tablespace)
+        else:
+            tablespace_sql = ""
+        if tablespace_sql:
+            tablespace_sql = " " + tablespace_sql
+
+        field_names = []
+        qn = self.connection.ops.quote_name
+        for f in fields:
+            field_names.append(style.SQL_FIELD(qn(f.column)))
+
+        index_name = "%s_%s" % (model._meta.db_table, self._digest([f.name for f in fields]))
+
+        return [
+            style.SQL_KEYWORD("DROP INDEX") + " " +
+            style.SQL_TABLE(qn(truncate_name(index_name, self.connection.ops.max_name_length()))) + " " +
+            ";",
+        ]
+
     def create_test_db(self, verbosity=1, autoclobber=False):
         """
         Creates a test database, prompting the user for confirmation if the
diff --git a/django/db/backends/mysql/creation.py b/django/db/backends/mysql/creation.py
index 8d72d11921..01efe8d35b 100644
--- a/django/db/backends/mysql/creation.py
+++ b/django/db/backends/mysql/creation.py
@@ -41,3 +41,29 @@ class DatabaseCreation(BaseDatabaseCreation):
     def sql_for_inline_foreign_key_references(self, model, field, known_models, style):
         "All inline references are pending under MySQL"
         return [], True
+
+    def sql_destroy_indexes_for_fields(self, model, fields, style):
+        if len(fields) == 1 and fields[0].db_tablespace:
+            tablespace_sql = self.connection.ops.tablespace_sql(fields[0].db_tablespace)
+        elif model._meta.db_tablespace:
+            tablespace_sql = self.connection.ops.tablespace_sql(model._meta.db_tablespace)
+        else:
+            tablespace_sql = ""
+        if tablespace_sql:
+            tablespace_sql = " " + tablespace_sql
+
+        field_names = []
+        qn = self.connection.ops.quote_name
+        for f in fields:
+            field_names.append(style.SQL_FIELD(qn(f.column)))
+
+        index_name = "%s_%s" % (model._meta.db_table, self._digest([f.name for f in fields]))
+
+        from ..util import truncate_name
+
+        return [
+            style.SQL_KEYWORD("DROP INDEX") + " " +
+            style.SQL_TABLE(qn(truncate_name(index_name, self.connection.ops.max_name_length()))) + " " +
+            style.SQL_KEYWORD("ON") + " " +
+            style.SQL_TABLE(qn(model._meta.db_table)) + ";",
+        ]