index on training_data(training_id)

init.sql

@@ -15,4 +15,5 @@ create table if not exists training_data(
     distance float not null,
     kcal int not null,
     constraint fk_training_id foreign key(training_id) references training(id) on delete cascade
-);
+);
+create index if not exists idx_training_data_training_id on training_data(training_id);