Prefer string interpolation to concatenation

lib/migrate.rb

@@ -14,16 +14,25 @@ module OpenStreetMap
       end
 
       def add_primary_key(table_name, column_name, _options = {})
-        execute "ALTER TABLE #{quote_table_name(table_name)} ADD PRIMARY KEY (#{quote_column_name(column_name)})"
+        table_name = quote_table_name(table_name)
+        column_name = quote_column_name(column_name)
+
+        execute "ALTER TABLE #{table_name} ADD PRIMARY KEY (#{column_name})"
       end
 
       def remove_primary_key(table_name)
-        execute "ALTER TABLE #{quote_table_name(table_name)} DROP PRIMARY KEY"
+        table_name = quote_table_name(table_name)
+
+        execute "ALTER TABLE #{table_name} DROP PRIMARY KEY"
       end
 
       def alter_primary_key(table_name, new_columns)
-        execute "ALTER TABLE #{quote_table_name(table_name)} DROP CONSTRAINT #{quote_table_name(table_name + '_pkey')}"
-        execute "ALTER TABLE #{quote_table_name(table_name)} ADD PRIMARY KEY (#{quote_column_name(new_columns)})"
+        constraint_name = quote_table_name("#{table_name}_pkey")
+        table_name = quote_table_name(table_name)
+        new_columns = quote_column_name(new_columns)
+
+        execute "ALTER TABLE #{table_name} DROP CONSTRAINT #{constraint_name}"
+        execute "ALTER TABLE #{table_name} ADD PRIMARY KEY (#{new_columns})"
       end
 
       def create_enumeration(enumeration_name, values)
@@ -35,7 +44,10 @@ module OpenStreetMap
       end
 
       def rename_enumeration(old_name, new_name)
-        execute "ALTER TYPE #{quote_table_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
+        old_name = quote_table_name(old_name)
+        new_name = quote_table_name(new_name)
+
+        execute "ALTER TYPE #{old_name} RENAME TO #{new_name}"
       end
     end
   end