Mairadb数据库基本操作之数据管理

Posted 2022-04-22 jks212454

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Mairadb数据库基本操作之数据管理

一、检查环境状态
二、mariadb的数据库增删改查
三、数据库表的增删改查
四、数据表的字段增删查改
五、数据表内容的增删查改

一、检查环境状态

[root@mster-k8s ~]# systemctl status mariadb
● mariadb.service - MariaDB 10.6.7 database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/mariadb.service.d
           └─migrated-from-my.cnf-settings.conf
   Active: active (running) since Wed 2022-04-20 11:50:35 CST; 12min ago
     Docs: man:mariadbd(8)
           https://mariadb.com/kb/en/library/systemd/
  Process: 11187 ExecStartPost=/bin/sh -c systemctl unset-environment _WSREP_START_POSITION (code=exited, status=0/SUCCESS)
  Process: 7810 ExecStartPre=/bin/sh -c [ ! -e /usr/bin/galera_recovery ] && VAR= ||   VAR=`cd /usr/bin/..; /usr/bin/galera_recovery`; [ $? -eq 0 ]   && systemctl set-environment _WSREP_START_POSITION=$VAR || exit 1 (code=exited, status=0/SUCCESS)
  Process: 7778 ExecStartPre=/bin/sh -c systemctl unset-environment _WSREP_START_POSITION (code=exited, status=0/SUCCESS)
 Main PID: 8024 (mariadbd)
   Status: "Taking your SQL requests now..."
    Tasks: 9
   Memory: 90.5M
   CGroup: /system.slice/mariadb.service
           └─8024 /usr/sbin/mariadbd

二、mariadb的数据库增删改查

1.本地进入mariadb

[root@mster-k8s ~]# mysql
Welcome to the MariaDB monitor.  Commands end with ; or \\g.
Your MariaDB connection id is 4
Server version: 10.6.7-MariaDB MariaDB Server
Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.
Type 'help;' or '\\h' for help. Type '\\c' to clear the current input statement.
MariaDB [(none)]>

2.增——创建一个数据库

MariaDB [(none)]> create database huawei;
Query OK, 1 row affected (0.000 sec)

3.查——查看数据库

MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| huawei             |
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| test               |
+--------------------+
6 rows in set (0.000 sec)

4.改——修改数据库名称

①查看数据库列表

MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| huawei_reduction   |
| information_schema |
| mysql              |
| performance_schema |
| redhat             |
| sys                |
+--------------------+

②新建空数据库

MariaDB [(none)]> create database mall;
Query OK, 1 row affected (0.000 sec)

③备份数据库

mysqldump -uroot -p123  huawei_reduction  > /backup/mariadb/huawei.sql

④恢复到空数据库

mysqld -uroot -p123  mall  < ./huawei.sql

⑤检查恢复后的数据库

MariaDB [(none)]> use mall
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 [mall]> 
MariaDB [mall]> show tables;
+----------------+
| Tables_in_mall |
+----------------+
| student        |
+----------------+
1 row in set (0.000 sec)

MariaDB [mall]> select * from student;
+----+--------+--------+------+-------+--------+-------+
| id | name   | gender | age  | class | course | grade |
+----+--------+--------+------+-------+--------+-------+
|  1 | 张三   |      0 |   18 |     3 | 语文   |    98 |
|  2 | 李四   |      0 |   17 |     3 | 数学   |    95 |
|  3 | 王五   |      1 |   16 |     2 | 物理   |    88 |
|  4 | 高峰   |      0 |   22 |     4 | 英语   |   100 |
|  5 | 陈林   |      1 |   15 |     5 | 化学   |    99 |
+----+--------+--------+------+-------+--------+-------+
5 rows in set (0.000 sec)

三、数据库表的增删改查

1.增——创建一张数据表

①进入某个空数据库

MariaDB [(none)]> create database test;
Query OK, 1 row affected (0.000 sec)

MariaDB [(none)]> use test;
Database changed
MariaDB [test]>

②创建数据表及其字段

CREATE TABLE IF NOT EXISTS `student`(
   `id` INT UNSIGNED AUTO_INCREMENT,
   `name` VARCHAR(100) NOT NULL,
   `gender` TINYINT NOT NULL,
   `age` INT UNSIGNED,
   `class` INT UNSIGNED,
   PRIMARY KEY ( `id` )
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

2查——查看数据表信息

①查看创建的表

MariaDB [test]> show tables;
+----------------+
| Tables_in_test |
+----------------+
| student        |
+----------------+
1 row in set (0.000 sec)

②查看表的字段

MariaDB [test]> show columns from student;
+--------+------------------+------+-----+---------+----------------+
| Field  | Type             | Null | Key | Default | Extra          |
+--------+------------------+------+-----+---------+----------------+
| id     | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| name   | varchar(100)     | NO   |     | NULL    |                |
| gender | tinyint(4)       | NO   |     | NULL    |                |
| age    | int(10) unsigned | YES  |     | NULL    |                |
| class  | int(10) unsigned | YES  |     | NULL    |                |
+--------+------------------+------+-----+---------+----------------+
5 rows in set (0.001 sec)

MariaDB [test]>

③查询创建student字段的语句

MariaDB [test]> show create table student;
+---------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table   | Create Table                                                                                                                                                                                                                                                                           |
+---------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| student | CREATE TABLE `student` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  `gender` tinyint(4) NOT NULL,
  `age` int(10) unsigned DEFAULT NULL,
  `class` int(10) unsigned DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb3 |
+---------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.000 sec)

MariaDB [test]>

④查看当前表所在数据库

MariaDB [test]> select database();
+------------+
| database() |
+------------+
| test       |
+------------+
1 row in set (0.000 sec)

⑤查询当前表的字段

MariaDB [test]> describe student;
+--------+------------------+------+-----+---------+----------------+
| Field  | Type             | Null | Key | Default | Extra          |
+--------+------------------+------+-----+---------+----------------+
| id     | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| name   | varchar(100)     | NO   |     | NULL    |                |
| gender | tinyint(4)       | NO   |     | NULL    |                |
| age    | int(10) unsigned | YES  |     | NULL    |                |
| class  | int(10) unsigned | YES  |     | NULL    |                |
+--------+------------------+------+-----+---------+----------------+
5 rows in set (0.001 sec)

MariaDB [test]>

3.改——改数据表的名称

MariaDB [test]> alter table student rename student01;
Query OK, 0 rows affected (0.008 sec)

4.删——删除表

MariaDB [test]> drop table student;
Query OK, 0 rows affected (0.055 sec)

MariaDB [test]>

四、数据表的字段增删查改

1.查——查询表中字段

①查询字段方法1

MariaDB [test]> show create table student;
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table   | Create Table                                                                                                                                                                                                                                                                        |
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| student | CREATE TABLE `student` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  `gender` tinyint(4) NOT NULL,
  `age` int(10) unsigned DEFAULT NULL,
  `class` int(10) unsigned DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.000 sec)

MariaDB [test]>

②查询字段方法2

MariaDB [test]> show create table student;
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Table   | Create Table                                                                                                                                                                                                                                                                        |
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| student | CREATE TABLE `student` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  `gender` tinyint(4) NOT NULL,
  `age` int(10) unsigned DEFAULT NULL,
  `class` int(10) unsigned DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
1 row in set (0.000 sec)

2.增——添加字段

MariaDB [test]>  alter table student add course tinyint;
Query OK, 0 rows affected (0.003 sec)
Records: 0  Duplicates: 0  Warnings: 0

3.改——修改字段

①修改字段类型

MariaDB [test]> alter table student modify   course VARCHAR(100);
Query OK, 0 rows affected (0.037 sec)              
Records: 0  Duplicates: 0  Warnings: 0

②修改字段名称

MariaDB [test]> alter table student change course Course VARCHAR(100) after name;
Query OK, 0 rows affected (0.026 sec)
Records: 0  Duplicates: 0  Warnings: 0

4.删——删除字段

MariaDB [test]>  alter table student drop Course;

五、数据表内容的增删查改

1.增——插入数据

①单条插入数据

insert into student ( name, gender, age, class, Course, grade ) values ( "张三", "0", "18", "3", "语文", "98" );
insert into student (name, gender, age, class, Course, grade) values ("李四", "0", "17", "3", "数学", "95");
insert into student (name, gender, age, class, Course, grade) values ( "王五", "1", "16", "2", "物理", "88");

②批量插入数据

insert into student ( name, gender, age, class, Course, grade ) values ( "高峰", "0", "22", "4", "英语", "100"), ( "陈林", "1", "15", "5", "化学", "99" );

2.改——修改数据

update student set gender=0 where name="王五" and id=5;

3.查——查询数据

①查询表内全部内容

MariaDB [test]> select * from student;
+----+--------+--------+--------+------+-------+-------+
| id | name   | Course | gender | age  | class | grade |
+----+--------+--------+--------+------+-------+-------+
|  1 | 张三   | 语文   |      0 |   18 |     3 |    98 |
|  2 | 高峰   | 英语   |      0 |   22 |     4 |   100 |
|  3 | 陈林   | 化学   |      1 |   15 |     5 |    99 |
|  4 | 李四   | 数学   |      0 |   17 |     3 |    95 |
|  5 | 王五   | 物理   |      0 |   16 |     2 |    88 |
+----+--------+--------+--------+------+-------+-------+
5 rows in set (0.000 sec)

②查询指定内容

MariaDB [test]> select name,age from student;
+--------+------+
| name   | age  |
+--------+------+
| 张三   |   18 |
| 高峰   |   22 |
| 陈林   |   15 |
| 李四   |   17 |
| 王五   |   16 |
+--------+------+
5 rows in set (0.000 sec)

MariaDB [test]>

4.删——删除数据

delete from student where name="王五";

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