func DeleteSubscription(db *pgx.ConnPool, userID, feedID int32) error {
if _, err := db.Prepare("deleteSubscription", deleteSubscriptionSQL); err != nil {
return err
}
if _, err := db.Prepare("deleteFeedIfOrphaned", deleteFeedIfOrphanedSQL); err != nil {
return err
}
tx, err := db.BeginIso(pgx.Serializable)
if err != nil {
return err
}
defer tx.Rollback()
_, err = tx.Exec("deleteSubscription", userID, feedID)
if err != nil {
return err
}
_, err = tx.Exec("deleteFeedIfOrphaned", feedID)
if err != nil {
return err
}
return tx.Commit()
}