code: func (db *Database) Exec(query string, args ...interface{}) error {
  	defer db.clear()
  	stmt := db.commonRawQuery(query, args...)
  	_, e := stmt.Exec(db.whereValues...)
  	return e
  }
docs: // Exec prepares and execute a raw query and replace placeholders (?) with the one supported by PostgreSQL
  // Exec panics if can't build the query
  // Use Exec instead of Raw when you don't need the results (or there's no result)