[18-03-09] I studied JDBC

I learnt JDBC today. I didn't use this function for long times because i used spring framework until now. However, i used this one again to study the basic of DB in Java. when i used it, i was so tired to use it because it repeats many times for adding functions. 

when i studied alone, i felt i need to study more about Database. Learning computer science makes me learn more. but i will do my best for it.