# SQL 複合主鍵
https://www.itread01.com/content/1547717253.html

https://www.itread01.com/content/1549211792.html

指令

ALTER TABLE LESSION_FLA
ADD CONSTRAINT FLA PRIMARY KEY (STU_NO, COUR_NO);


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 SELECT * FROM LESSION_TIME;
 
 SELECT * FROM LESSION_COURSE JOIN LESSION_TIME ON LESSION_COURSE.COUR_NO=LESSION_TIME.COUR_NO;
 
  SELECT * FROM LESSION_COURSE JOIN LESSION_TIME ON LESSION_COURSE.COUR_NO=LESSION_TIME.COUR_NO;
 
  SELECT * FROM LESSION_COURSE JOIN LESSION_DETAIL ON LESSION_DETAIL.COUR_NO=LESSION_COURSE.COUR_NO 
  JOIN LESSION_TIME  ON LESSION_TIME.LESSION_TIME_NO=LESSION_DETAIL.LESSION_TIME_NO;

我們要違反正規化~

不違反 照著er做

ALTER SESSION SET NLS_DATE_FORMAT = 'yyyy-mm-dd HH24:MI:SS';

SELECT * FROM LESSON 
JOIN LESSON_DETAIL ON LESSON_DETAIL.LESSNO=LESSON.LESSNO
JOIN LESSON_TIME  ON LESSON_TIME.LTIME_NO=LESSON_DETAIL.LTIME_NO
WHERE LESSON_DETAIL.LESSNO=LESSON.LESSNO and LESSON_TIME.LTIME_NO=LESSON_DETAIL.LTIME_NO;

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# 教練

ALTER TABLE activity
ADD FOREIGN KEY (c_no) REFERENCES coach(coach_no);
----
教練修改 活動狀態
UPDATE activity
SET A_STATUS=1
WHERE A_no=01;