migrator.rb in also_migrate-0.1.1

- old
+ new

@@ -17,10 +17,13 @@
         Object.subclasses_of(ActiveRecord::Base).each do |klass|
           if klass.respond_to?(:also_migrate_config)
             AlsoMigrate.create_tables(klass)
           end
         end
+      rescue Exception => e
+        puts "AlsoMigrate error: #{e.message}"
+        puts e.backtrace.join("\n")
       ensure
         migrate_without_also_migrate
       end
       
       module AlsoMigrate
@@ -30,10 +33,11 @@
             ActiveRecord::Base.connection
           end
         
           def create_tables(klass)
             config = klass.also_migrate_config
+            return unless config
             old_table = klass.table_name
             config.each do |config|
               options = config[:options]
               config[:tables].each do |new_table|
                 if !connection.table_exists?(new_table) && connection.table_exists?(old_table)
@@ -45,61 +49,28 @@
                       'ENGINE=' + connection.select_one(<<-SQL)['Engine']
                         SHOW TABLE STATUS
                         WHERE Name = '#{old_table}'
                       SQL
                     end
-                  connection.execute(<<-SQL)
-                    CREATE TABLE #{new_table} #{engine}
-                    AS SELECT #{columns.join(',')}
-                    FROM #{old_table}
-                    WHERE false;
-                  SQL
                   indexes = options[:indexes]
-                  indexes ||= indexed_columns(old_table)
-                  indexes.each do |column|
-                    connection.add_index(new_table, column)
+                  if indexes
+                    connection.execute(<<-SQL)
+                      CREATE TABLE #{new_table} #{engine}
+                      AS SELECT #{columns.join(',')}
+                      FROM #{old_table}
+                      WHERE false;
+                    SQL
+                    indexes.each do |column|
+                      connection.add_index(new_table, column)
+                    end
+                  else
+                    connection.execute(<<-SQL)
+                      CREATE TABLE #{new_table}
+                      LIKE #{old_table};
+                    SQL
                   end
                 end
               end
-            end
-          end
-
-          def indexed_columns(table_name)
-            # MySQL
-            if connection.class.to_s.include?('Mysql')
-              index_query = "SHOW INDEX FROM #{table_name}"
-              connection.select_all(index_query).collect do |r|
-                r["Column_name"]
-              end
-            # PostgreSQL
-            # http://stackoverflow.com/questions/2204058/show-which-columns-an-index-is-on-in-postgresql/2213199
-            elsif connection.class.to_s.include?('PostgreSQL')
-              index_query = <<-SQL
-                select
-                  t.relname as table_name,
-                  i.relname as index_name,
-                  a.attname as column_name
-                from
-                  pg_class t,
-                  pg_class i,
-                  pg_index ix,
-                  pg_attribute a
-                where
-                  t.oid = ix.indrelid
-                  and i.oid = ix.indexrelid
-                  and a.attrelid = t.oid
-                  and a.attnum = ANY(ix.indkey)
-                  and t.relkind = 'r'
-                  and t.relname = '#{table_name}'
-                order by
-                  t.relname,
-                  i.relname
-              SQL
-              connection.select_all(index_query).collect do |r|
-                r["column_name"]
-              end
-            else
-              raise 'AlsoMigrate does not support this database adapter'
             end
           end
         end
       end
     end
\ No newline at end of file