关于MySQL 事务,视图,索引,数据库备份,恢复

时间:2023-03-08 23:56:34
关于MySQL 事务,视图,索引,数据库备份,恢复
  1.   /*创建数据库*/

CREATE DATABASE `mybank`;
/*创建表*/
USE mybank;
CREATE TABLE `bank`(
    `customerName` CHAR(10),        #用户名
    `currentMoney` DECIMAL(10,2)         #当前余额
);
/*插入数据*/
INSERT INTO `bank` (`customerName`,`currentMoney`) VALUES ('张三',1000);
INSERT INTO `bank` (`customerName`,`currentMoney`) VALUES ('李四',1);

  2. --转账测试:张三希望通过转账,直接汇钱给李四500元

UPDATE `bank` SET `currentMoney` =`currentMoney`-500
    WHERE `customerName` = '张三';
UPDATE `bank` SET `currentMoney` =`currentMoney`+500
    WHERE `customerName` = '李四';

 3. 执行事务 并提交事务

USE mybank;

/*设置结果集以gbk编码格式显示*/
SET NAMES gbk;

/*开始事务*/
BEGIN;
UPDATE `bank` SET `currentMoney` =`currentMoney`-500
    WHERE `customerName` = '张三';
UPDATE `bank` SET `currentMoney` =`currentMoney`+500
    WHERE `customerName` = '李四';
COMMIT;        #提交事务,写入硬盘

 4. 开始事务  回滚事务
BEGIN;
UPDATE `bank` SET `currentMoney` = `currentMoney` -1000 WHERE `customerName` = '张三';
/*回滚*/
ROLLBACK;

5.设置自动提交关闭或开启

/*关闭事务自动提交*/
SET autocommit = 0;

/*转账*/
UPDATE `bank` SET `currentMoney` =`currentMoney`-500
    WHERE `customerName` = '张三';
UPDATE `bank` SET `currentMoney` =`currentMoney`+500
    WHERE `customerName` = '李四';
    /*提交*/
COMMIT;
UPDATE `bank` SET `currentMoney` = `currentMoney` -1000 WHERE `customerName` = '张三';

/*回滚事务*/
ROLLBACK;

 6. 创建视图

/*当前数据库*/
USE myschool;

DROP VIEW IF EXISTS `view_student_result`;

/*创建视图*/
CREATE VIEW `view_student_result`
AS

/*需要创建视图的数据*/
SELECT `studentName` AS 姓名,student.`studentNo` 学号,`studentResult` AS 成绩,`subjectName` AS 课程名称.`examDate` AS 考试日期
FROM `student`
INNER JOIN `result` ON `student`.`studentNo` = `result`.`studentNo`
INNER JOIN `subject` ON `result`.`subjectNo` = `subject`.`studentNo`
WHERE `subject`.`subjectNo`=(
    SELECT `subjectNo` FROM `subject` WHERE `subjectName` = 'Logic Java'
)AND `examDate` =(
    SELECT MAX(`examDate`) FROM `result`.`subject` WHERE `result`.`subjectNo` = `subject`.`subjectNo`
    AND `subjectName` = 'Logic Java'
);

7. 创建索引

USE myschool;

/*创建索引*/
CREATE INDEX `index_student_studentName`
ON `student`(`studentName`);

8. 使用DOS命令备份数据库

mysqldump -u username -h -ppassword

dbname[tbname1 [,tbname2]........] > filename.sql

例:

mysqldump -u root -p myschool student > d:\backup\myschool.sql

EnterPassword:

9. 使用后DOS命令恢复数据库

  1) .恢复数据库前先在MySQL服务器中创建新的数据库.

  2). 执行 mysql -u username -p [dbname]  <filename.sql

例:

mysql -u root -p schoolDB <  d:\backup\myschool.sql

10. 使用source命令恢复数据库

  语法:   source  filename;

例:

/*创建数据库*/
CREATE DATABASE myschoolDB2;
USE myschoolDB2;
/*恢复数据库*/
source 'd:\backup\myschool.sql';

11. 将表数据导出到文本文件

语法: select 列名 from 表名 [where 条件,条件2......]

into outfile 'filename' ;

例:

SELECT * FROM `result` WHERE `subjectNo` =

  (SELECT  `subjectNo` FROM `subject`  WHERE `subjectName` = 'Logic Java')

  INTO OUTFILE 'd: /backup/result.txt';

12. 将文本文件导入到数据表

语法: LOAD DATA INFILE 'filename' INTO TABLE 'tablename ';

  1) . 先创建导入数据的表结构

    USE myschoolDB2;
    /*创建result表结构*/
    CREATE TABLE `result`
    (
    `studentNo` INT(4) NOT NULL COMMENT '学号',
    `subjectNo` INT(4) NOT NULL COMMENT '课程编号',
    `examDate` DATETIME NOT NULL COMMENT '考试日期',
    `studentResult` INT(4) NOT NULL COMMENT '考试成绩',
    PRIMARY KEY (`studentNo`,`subjectNo`,`examDate`)
    )ENGINE = INNODB DEFAULT CHARSET utf8;

  2).导入数据
    LOAD DATA INFILE '路径.txt' INTO TABLE result;
    /*查看result表数据*/
    SELECT * FROM result;