MYSQL数据库备份与恢复
数据库常用备份方案
数据库备份方案:
- 全量备份
- 增量备份
- 差异备份
备份方案 | 特点 |
全量备份 | 全量备份就是指对某一个时间点上的所有数据或应用进行的一个完全拷贝。 数据恢复快。 备份时间长 |
增量备份 | 增量备份是指在一次全备份或上一次增量备份后,以后每次的备份只需备份 与前一次相比增加和者被修改的文件。这就意味着,第一次增量备份的对象 是进行全备后所产生的增加和修改的文件;第二次增量备份的对象是进行第一次增量 备份后所产生的增加和修改的文件,如此类推。 没有重复的备份数据 备份时间短 恢复数据时必须按一定的顺序进行 |
差异备份 | 备份上一次的完全备份后发生变化的所有文件。 差异备份是指在一次全备份后到进行差异备份的这段时间内 对那些增加或者修改文件的备份。在进行恢复时,我们只需对第一次全量备份和最后一次差异备份进行恢复。 |
mysql备份工具mysqldump
语法:
- mysqldump [OPTIONS] database [tables …]
- mysqldump [OPTIONS] --all-databases [OPTIONS] - mysqldump [OPTIONS] --databases [OPTIONS] DB1 [DB2 DB3…]
常用的OPTIONS:
- uUSERNAME //指定数据库用户名
- hHOST //指定服务器主机,请使用ip地址
- pPASSWORD //指定数据库用户的密码
- P# //指定数据库监听的端口,这里的#需用实际的端口号代替,如-P3307
全量备份
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| student |
+--------------------+
4 rows in set (0.000 sec)
MariaDB [(none)]>
MariaDB [student]> select * from bzm;
+----+-------------+------+
| id | name | age |
+----+-------------+------+
| 1 | tom | 20 |
| 2 | jerry | 23 |
| 3 | wangqing | 25 |
| 4 | sean | 28 |
| 5 | zhangsan | 26 |
| 6 | zhangsan | 20 |
| 7 | lisi | 50 |
| 8 | chenshuo | 10 |
| 9 | wangwu | 3 |
| 10 | qiuyi | 15 |
| 11 | qiuxiaotian | 20 |
+----+-------------+------+
11 rows in set (0.000 sec)
MariaDB [student]>
[root@centos8-1 ~]# mkdir mysqldump
[root@centos8-1 ~]# cd mysqldump/
[root@centos8-1 mysqldump]# ls
[root@centos8-1 mysqldump]# mysqldump -u root -p1 --all-databases > all-13174897.sql
[root@centos8-1 mysqldump]# ls
all-13174897.sql
[root@centos8-1 mysqldump]#
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| student |
+--------------------+
4 rows in set (0.000 sec)
MariaDB [(none)]>
MariaDB [(none)]> drop database student;
Query OK, 1 row affected (0.004 sec)
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
+--------------------+
3 rows in set (0.000 sec)
MariaDB [(none)]>
[root@centos8-1 mysqldump]# mysql -u root -p1 < all-13174897.sql
[root@centos8-1 mysqldump]#
MariaDB [(none)]> show databases;
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| student |
+--------------------+
4 rows in set (0.000 sec)
MariaDB [(none)]> use student
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
MariaDB [student]> select * from bzm;
+----+-------------+------+
| id | name | age |
+----+-------------+------+
| 1 | tom | 20 |
| 2 | jerry | 23 |
| 3 | wangqing | 25 |
| 4 | sean | 28 |
| 5 | zhangsan | 26 |
| 6 | zhangsan | 20 |
| 7 | lisi | 50 |
| 8 | chenshuo | 10 |
| 9 | wangwu | 3 |
| 10 | qiuyi | 15 |
| 11 | qiuxiaotian | 20 |
+----+-------------+------+
11 rows in set (0.000 sec)
MariaDB [student]>
差异备份
MariaDB [student]> select * from bzm;
+----+-------------+------+
| id | name | age |
+----+-------------+------+
| 1 | tom | 20 |
| 2 | jerry | 23 |
| 3 | wangqing | 25 |
| 4 | sean | 28 |
| 5 | zhangsan | 26 |
| 6 | zhangsan | 20 |
| 7 | lisi | 50 |
| 8 | chenshuo | 10 |
| 9 | wangwu | 3 |
| 10 | qiuyi | 15 |
| 11 | qiuxiaotian | 20 |
+----+-------------+------+
11 rows in set (0.000 sec)
MariaDB [student]>
[root@centos8-1 mysqldump]# ls
all-13174897.sql
[root@centos8-1 mysqldump]# mysqldump -u root -p student bzm > size-14366767.sql
[root@centos8-1 mysqldump]# ls
all-13174897.sql size-14366767.sql
[root@centos8-1 mysqldump]#
MariaDB [student]> show tables;
+-------------------+
| Tables_in_student |
+-------------------+
| bzm |
+-------------------+
1 row in set (0.000 sec)
MariaDB [student]>
MariaDB [student]> drop table bzm;
Query OK, 0 rows affected (0.003 sec)
MariaDB [student]> show tables;
Empty set (0.001 sec)
MariaDB [student]>
[root@centos8-1 mysqldump]# mysql -u root -p1 student < size-14366767.sql
[root@centos8-1 mysqldump]#
MariaDB [(none)]> use student
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
MariaDB [student]> show tables;
+-------------------+
| Tables_in_student |
+-------------------+
| shenlongfei |
+-------------------+
1 row in set (0.001 sec)
MariaDB [student]>
MariaDB [student]> select * from bzm;
+----+-------------+------+
| id | name | age |
+----+-------------+------+
| 1 | tom | 20 |
| 2 | jerry | 23 |
| 3 | wangqing | 25 |
| 4 | sean | 28 |
| 5 | zhangsan | 26 |
| 6 | zhangsan | 20 |
| 7 | lisi | 50 |
| 8 | chenshuo | 10 |
| 9 | wangwu | 3 |
| 10 | qiuyi | 15 |
| 11 | qiuxiaotian | 20 |
+----+-------------+------+
11 rows in set (0.001 sec)
MariaDB [student]>
sql语句
group by
GROUP BY 语句用于结合聚合函数,根据一个或多个列对结果集进行分组。
SQL GROUP BY 语法
SELECT column_name, aggregate_function(column_name)
FROM table_name
WHERE column_name operator value
GROUP BY column_name;
test 表:
MariaDB [cha]> select *from test;
+----------+------+
| name | age |
+----------+------+
| xiaoming | 10 |
| xiaofang | 20 |
| xiaowu | 25 |
| xiaohu | 14 |
| xiaoming | 11 |
| xiaohu | 15 |
+----------+------+
inner join
sql语句如下:
select * from A
innerjoin B
on A.aID = B.aID
MariaDB [cha]> select *from A inner join B on A.aID = B.aID;
+-----+-----------+-----+----------+
| aID | aNum | aID | aNum |
+-----+-----------+-----+----------+
| 1 | a20050111 | 1 | 20050111 |
| 2 | a20050112 | 2 | 20050112 |
| 3 | a20050113 | 3 | 20050113 |
| 4 | a20050114 | 4 | 20050114 |
+-----+-----------+-----+----------+
4 rows in set (0.00 sec)
inner join、left join、right join
内连接只返回满足连接条件的数据行,外连接不只列出与连接条件相匹配的行,而是列出左表(左外连接时)、右表(右外连接时)或两个表(全外连接时)中所有符合搜索条件的数据行。
外连接分为左外连接、右外链接、全外连接三种。
1)LEFT JOIN或LEFT OUTER JOIN
左向外联接的结果集包括 LEFT OUTER子句中指定的左表的所有行,而不仅仅是联接列所匹配的行。如果左表的某行在右表中没有匹配行,则在相关联的结果集行中右表的所有选择列表列均为空值。
2)RIGHT JOIN 或 RIGHT OUTER JOIN
右向外联接是左向外联接的反向联接。将返回右表的所有行。如果右表的某行在左表中没有匹配行,则将为左表返回空值。
inner join(等值联接)
MariaDB [student]> select shenlongfei1.*,shenlongfei.* from shenlongfei1 inner join shenlongfei on shenlongfei1.age=shenlongfei.age;
+----+------+------+----+-------+------+
| id | name | age | id | name | age |
+----+------+------+----+-------+------+
| 3 | fei | 23 | 2 | jerry | 23 |
+----+------+------+----+-------+------+
1 row in set (0.000 sec)
MariaDB [student]>
left join(左联接)
MariaDB [student]> select shenlongfei1.*,shenlongfei.* from shenlongfei1 left join shenlongfei on shenlongfei1.age=shenlongfei.age;
+----+------+------+------+-------+------+
| id | name | age | id | name | age |
+----+------+------+------+-------+------+
| 3 | fei | 23 | 2 | jerry | 23 |
| 1 | shen | 12 | NULL | NULL | NULL |
| 2 | long | 53 | NULL | NULL | NULL |
+----+------+------+------+-------+------+
3 rows in set (0.001 sec)
MariaDB [student]>
right join(右联接)
MariaDB [student]> select shenlongfei1.*,shenlongfei.* from shenlongfei1 right join shenlongfei on shenlongfei1.age=shenlongfei.age;
+------+------+------+----+-------------+------+
| id | name | age | id | name | age |
+------+------+------+----+-------------+------+
| 3 | fei | 23 | 2 | jerry | 23 |
| NULL | NULL | NULL | 1 | tom | 20 |
| NULL | NULL | NULL | 3 | wangqing | 25 |
| NULL | NULL | NULL | 4 | sean | 28 |
| NULL | NULL | NULL | 5 | zhangsan | 26 |
| NULL | NULL | NULL | 6 | zhangsan | 20 |
| NULL | NULL | NULL | 7 | lisi | 50 |
| NULL | NULL | NULL | 8 | chenshuo | 10 |
| NULL | NULL | NULL | 9 | wangwu | 3 |
| NULL | NULL | NULL | 10 | qiuyi | 15 |
| NULL | NULL | NULL | 11 | qiuxiaotian | 20 |
+------+------+------+----+-------------+------+
11 rows in set (0.000 sec)
MariaDB [student]>