Make to primary key instead of an unique index for internal tables

2 files changed, 4 insertions, 15 deletions

diff --git a/activerecord/lib/active_record/internal_metadata.rb b/activerecord/lib/active_record/internal_metadata.rb
index 10fee4dca2..641b137851 100644
--- a/activerecord/lib/active_record/internal_metadata.rb
+++ b/activerecord/lib/active_record/internal_metadata.rb
@@ -18,10 +18,6 @@ module ActiveRecord
         "#{table_name_prefix}#{ActiveRecord::Base.internal_metadata_table_name}#{table_name_suffix}"
       end
 
-      def index_name
-        "#{table_name_prefix}unique_#{ActiveRecord::Base.internal_metadata_table_name}#{table_name_suffix}"
-      end
-
       def []=(key, value)
         first_or_initialize(key: key).update_attributes!(value: value)
       end
@@ -38,10 +34,8 @@ module ActiveRecord
       def create_table
         unless table_exists?
           connection.create_table(table_name, id: false) do |t|
-            t.column :key,   :string, null: false, limit: KEY_LIMIT
-            t.column :value, :string
-            t.index  :key, unique: true, name: index_name
-
+            t.string :key, primary_key: true, limit: KEY_LIMIT
+            t.string :value
             t.timestamps
           end
         end
diff --git a/activerecord/lib/active_record/schema_migration.rb b/activerecord/lib/active_record/schema_migration.rb
index 8f0ab2b55b..a5b693c349 100644
--- a/activerecord/lib/active_record/schema_migration.rb
+++ b/activerecord/lib/active_record/schema_migration.rb
@@ -16,22 +16,17 @@ module ActiveRecord
         "#{table_name_prefix}#{ActiveRecord::Base.schema_migrations_table_name}#{table_name_suffix}"
       end
 
-      def index_name
-        "#{table_name_prefix}unique_#{ActiveRecord::Base.schema_migrations_table_name}#{table_name_suffix}"
-      end
-
       def table_exists?
         ActiveSupport::Deprecation.silence { connection.table_exists?(table_name) }
       end
 
       def create_table(limit=nil)
         unless table_exists?
-          version_options = {null: false}
+          version_options = { primary_key: true }
           version_options[:limit] = limit if limit
 
           connection.create_table(table_name, id: false) do |t|
-            t.column :version, :string, version_options
-            t.index  :version, unique: true, name: index_name
+            t.string :version, version_options
           end
         end
       end