MySQL Database table maintainer

To export table + data

mysqldump  -u root -p  Course > Course.sql

To export table only

mysqldump  -u root -p -d Course > table_only.sql

To export data only

mysqldump  -u root -p --no-create-info  Course  > data_only.sql

To import

mysql -u root -p Course < Course.sql

How to add foreign key

https://www.youtube.com/watch?v=7HTAX0dfJqg
先這一個一般的field int(eg: tId，但如果被參考的foreign key有unsinged attribute，那我的tId也要是unsigned int，不然會無法成功…
ALTER TABLE `Course` ADD CONSTRAINT `TeachForeignKey` FOREIGN KEY (`tId`) REFERENCES `Teacher`(`tId`) ON DELETE RESTRICT ON UPDATE RESTRICT;

mysql> mysql> SELECT Course.*,Teacher.tName FROM Course JOIN Teacher ON Teacher.tId = Course.tId;

+-----+-----+--------------+----------------+---------------------+------+-----+------------+ | cId | tId | cName | cDesc | dateTime | unit | max | tName | +-----+-----+--------------+----------------+---------------------+------+-----+------------+ | 2 | 0 | Internet | Internet | 2022-06-16 00:00:00 | 4 | 25 | 葉問 | | 3 | 0 | DataBase2 | MySQL_Database | 2022-06-16 22:00:34 | 4 | 25 | 葉問 | | 5 | 0 | 我愛紅娘 | 紅娘愛我 | 2022-06-16 00:00:00 | 4 | 25 | 葉問 | | 6 | 6 | 五燈獎 | 三顆星 | 2022-06-16 00:00:00 | 4 | 25 | 大灰狼2 | +-----+-----+--------------+----------------+---------------------+------+-----+------------+