MySQL time, time zone, auto fill 0

Database time update problem 2022/4/13

When the database updates user information , The registration time will be updated every time , I'm really confused about this wave .

At first I thought it was mybatis By the way, I updated the registration time , Then I checked the code , No problem found , open mybatis Look at the log ,sql The statements are also correct , I don't see the code that updates the registration time at all .

Think about it. , Maybe it's the database . It is found that the registration time field is checked Update... Based on the current timestamp The option to , Suddenly understand , The original option is that this field will be updated every time the content is updated . Test the code after canceling , Everything is all right .

Database time zone error 2022/4/20

Today, I debugged an interface , Involving time , I am from Java Get the current time and then go to the database （ In fact, I think using the database now It's fine too ）, Then something went wrong , The time saved is several hours slower than the actual time .

I think about it , Will not be new Timestamp(System.currentTimeMillis()); It's a matter of time for this code to get , Tested decisively , Discovery is not its problem , That must be the problem of the database , But I think the time when the database automatically updates the timestamp is correct . Think about it. , Maybe when you turn around , Time zone problem .

Written before yaml When configuring a file , Always follow the teacher's writing , That's what the teacher wrote jdbc:mysql://127.0.0.1:3306/blog?serverTimezone=UTC , It turned out that I was 100 degrees , good heavens , This time zone is the universal time , It's slower than Beijing 8 Hours , Change to serverTimezone=Asia/Shanghai It's settled. .

Database population 0 2022/4/20

stay mysql5.6 in ,int And other digital types can be selected fill 0 .

fill 0 It does not mean that the default value is 0, But to On display , Fill to the left by default 0, namely 20 It will be displayed. 0000000020 , Of course, on the left 0 Not necessarily as much as I wrote , Here I am just making an analogy .

If you don't want to automatically fill so many 0, Cancel... Directly Fill in zero This is the option .