This time i started to learn about firebase Database. Different from sql databse, firebase does not have a “where” query to simply find a data with a certain keyword. While sql many people refer to as a query database, firebase is more like a hierarchy database. Knowing this means that everything that i learn from previous semester’s  is useless. Every plan that i thinking has failed before the project even began. this simply demoralized me to the extend that every motivation i have vanished in an instant.