小问题 初学
DECLARE
v_Majorstudents.major%TYPE;
v_CreditIncreaseNUMBER := 3;
BEGIN
v_Major := 'History';
UPDATE students
SET current_credits = current_credits + v_CreditIncrease
WHERE major = v_Major;
END;
/
2．
DECLARE
v_StudentIDstudents.id%TYPE;
BEGIN
SELECT student_sequence.NEXTVAL
INTO v_StudentID
FROM dual;
INSERT INTO students (id, first_name, last_name)
VALUES (v_StudentID, 'Timothy', 'Taller');
INSERT INTO students (id, first_name, last_name)
VALUES (student_sequence.NEXTVAL, 'Patrick', 'Poll');
END
请帮忙分析一下这两段代码分别完成什么工作 谢谢哈

------解决方案--------------------
第一段代码：
更新students表，

第二段代码：
先取出student_sequence.NEXTVAL，存到变量v_StudentID中；
再往students 写入数据。
------解决方案--------------------
你不会把空格写写好？定义变量能这么连着写吗？
------解决方案--------------------
DECLARE
v_Majorstudents.major%TYPE;
v_CreditIncreaseNUMBER := 3;
BEGIN
v_Major := 'History';
UPDATE students
SET current_credits = current_credits + v_CreditIncrease
WHERE major = v_Major;
END;

--UPDATE students
SET current_credits = current_credits + 3
WHERE major = 'History';
更新 students major = 'History' 将current_credits = current_credits + 3

DECLARE
v_StudentIDstudents.id%TYPE;
BEGIN
SELECT student_sequence.NEXTVAL
INTO v_StudentID
FROM dual;
INSERT INTO students (id, first_name, last_name)
VALUES (v_StudentID, 'Timothy', 'Taller');
INSERT INTO students (id, first_name, last_name)
VALUES (student_sequence.NEXTVAL, 'Patrick', 'Poll');
END
--INSERT INTO students (id, first_name, last_name)
VALUES (student_sequence.NEXTVAL, 'Timothy', 'Taller');

INSERT INTO students (id, first_name, last_name)
VALUES (student_sequence.NEXTVAL, 'Patrick', 'Poll');

students 插入二条记录


------解决方案--------------------
DECLARE
v_Majorstudents.major%TYPE;
v_CreditIncreaseNUMBER := 3;
BEGIN
v_Major := 'History';
UPDATE students
SET current_credits = current_credits + v_CreditIncrease
WHERE major = v_Major;
END;

--UPDATE students
SET current_credits = current_credits + 3
WHERE major = 'History';
更新 students major = 'History' 将current_credits = current_credits + 3

DECLARE
v_StudentIDstudents.id%TYPE;
BEGIN
SELECT student_sequence.NEXTVAL
INTO v_StudentID
FROM dual;
INSERT INTO students (id, first_name, last_name)
VALUES (v_StudentID, 'Timothy', 'Taller');
INSERT INTO students (id, first_name, last_name)
VALUES (student_sequence.NEXTVAL, 'Patrick', 'Poll');
END
--INSERT INTO students (id, first_name, last_name)
VALUES (student_sequence.NEXTVAL, 'Timothy', 'Taller');

INSERT INTO students (id, first_name, last_name)
VALUES (student_sequence.NEXTVAL, 'Patrick', 'Poll');

students 插入二条记录


------解决方案--------------------
DECLARE
v_Majorstudents.major%TYPE;
v_CreditIncreaseNUMBER := 3;
BEGIN
v_Major := 'History';
UPDATE students
SET current_credits = current_credits + v_CreditIncrease
WHERE major = v_Major;
END;

--UPDATE students
SET current_credits = current_credits + 3
WHERE major = 'History';
更新 students major = 'History' 将current_credits = current_credits + 3

DECLARE
v_StudentIDstudents.id%TYPE;
BEGIN
SELECT student_sequence.NEXTVAL
INTO v_StudentID
FROM dual;
INSERT INTO students (id, first_name, last_name)
VALUES (v_StudentID, 'Timothy', 'Taller');
INSERT INTO students (id, first_name, last_name)