視圖 單表數據備份 多表整庫備份

# --視圖:單表+多表

# create view my_v1 as

# select * from my_student;

# create view my_v2 as

# select * from my_student;

# create view my_v3 as

# select * from my_student as s

# left join my_class as c on s.c_id

# =c.id;--id修復

# --多表視圖

# create view my_v3 as

# select s.*,c.c_name,c.room

# from my_student as s

# left join my_class as c

# on s.c_id=c.id;

# --查看視圖創建語句

# show create view my_v3\G

# --視圖使用

# select * from my_v1;

# select * from my_v2;

# select * from my_v3;

# --修改視圖

# alter view my_v1 as

# select id,name,age,sex,height,

# c_id

# from my_student;

# --創建視圖

# create view my_v4 as select *

# from my_student;

# --刪除視圖

# drop view my_v4;

# --多表視圖插入數據

# insert into my_v3

# values(null,'bc2019006','張三豐','男',150,180,1,'Python1907','B407');

# 將學生表的學號字段設置成不允許為空

# alter table my_student modify

# number char(10) not null unique;

# --單表視圖插入數據:視圖不包括所有不允許為空的字段

# insert into my_v1

# values(null,'張三豐',150,'男',180,1);--失敗(學號不允許為空)

# --單表視圖插入數據

# insert into my_v2

# values(2,'Python1811','B410');

# --多表視圖刪除數據

# delete from my_v3 where id=1;

# --單表視圖刪除數據

# delete from my_v2 where id=4;

# --多表視圖更新數據

# update my_v3 set c_id=3 where id=5;

# --視圖:age字段限制更新

# create view my_v4 as

# select * from my_student where

# age>30 with check option;

# 表示視圖的數據來源都是年齡大于30歲,是由where age>30決定的

# --with check

# option決定通過視圖更新的時候,不能將已經的到的數據age>30的改成<30的

# --將視圖可以查到數據改成年齡小于30的

# update my_v4 set age=29 where id=3;

# --可以修改數據:可以改,但是視圖查不到

# update my_v4 set age=32 where id=2;

# --獲取所有班級中最高的一個學生

# create view my_v5 as

# select * from my_v5 group by c_id;

# select * from my_student group by c_id order by height desc;

# --指定算法為臨時表算法

# create algorithm=temptable view

# my_v6 as select * from my_student order by height desc;

# select * from my_v6 group by c_id;

# --查看MySQL的版本

# select @@version;

# --創建myisam表

# create table my_myisam(

# id int

# )charset utf8 engine=myisam;

# --向my_myisam表插入幾條記錄

# insert into my_myisam values(1),(2),(3);

# --單表數據備份

# select * into outfile

# 'D:/1907/web/student.txt'

# --還原數據

# load data infile

# 'D:/1907/web/student.txt'

# into table my_class

# --字段處理

# fields

# enclosed by '""'

# 數據使用雙引號包裹

# terminated by'|'

# 使用數顯分隔字段數據

# --行處理

# lines

# starting by 'START'

# --SQL備份

# mysqldump -uroot -p123456

# mydatabase my_student > D:/1907/web/student.sql

# --整庫備份

# mysqldump -uroot -p123456

# mydatabase my_student > D:/1907/web/student.sql

# --還原數據:mysql客戶端還原

# mysql -uroot -p123456 mydatabase < D:/1907/web/student/sql

# --SQL指令還原SQL備份

# source D:/1907/web/student.sql;

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