MySQL表操作

1.介绍

　　表就相当于文件，表中的一条记录就相当与文件的一行内容，不同的是，表中的一条记录有对应的标题，成为表的字段。

2.创建表

2.1语法

create table 表名(

字段名1 类型[(宽度) 约束条件],

字段名2 类型[(宽度) 约束条件],

字段名3 类型[(宽度) 约束条件],

);

注意：

    1. 必须进入数据库中才能创建表
    2. 标点符号均为英文标点符号

    3. 在同一张表中，字段名是不能相同的

    4. 宽度和约束条件为可选项

    5. 字段名和类型是必须的

2.2范例

1-使用默认格式创建表

mysql> use python25;

Database changed

mysql> show tables;

Empty set (0.00 sec)

mysql> create table test1(id int,

    -> name char(11),

    -> sex enum('male', 'female'),

    -> hobby set('swiming', 'running', 'basketball'));

Query OK, 0 rows affected (0.02 sec)

mysql> desc test1;

+-------+---------------------------------------+------+-----+---------+-------+

| Field | Type                                  | Null | Key | Default | Extra |

+-------+---------------------------------------+------+-----+---------+-------+

| id    | int(11)                               | YES  |     | NULL    |       |

| name  | char(11)                              | YES  |     | NULL    |       |

| sex   | enum('male','female')                 | YES  |     | NULL    |       |

| hobby | set('swiming','running','basketball') | YES  |     | NULL    |       |

+-------+---------------------------------------+------+-----+---------+-------+

4 rows in set (0.00 sec)

2-自定义格式创建表

# 指定字符编码

mysql> create table test3 (

    -> id int,

    -> name char(10),

    -> age int,

    -> sex enum('male', 'female'),

    -> phone char(11),

    -> job char(10)

    -> ) charset=utf8;

Query OK, 0 rows affected (0.03 sec)

#指定存储引擎

mysql> create table test4 (

    -> id int,

    -> name char(10),

    -> age int,

    -> sex enum('male', 'female'),

    -> phone char(11),

    -> job char(10)

    -> ) ENGINE=MyISAM;

Query OK, 0 rows affected (0.01 sec)

3-查看表结构、创建表的语句

# 查看表结构

mysql> show columns from test1;

+-------+---------------------------------------+------+-----+---------+-------+

| Field | Type                                  | Null | Key | Default | Extra |

+-------+---------------------------------------+------+-----+---------+-------+

| id    | int(11)                               | YES  |     | NULL    |       |

| name  | char(11)                              | YES  |     | NULL    |       |

| sex   | enum('male','female')                 | YES  |     | NULL    |       |

| hobby | set('swiming','running','basketball') | YES  |     | NULL    |       |

+-------+---------------------------------------+------+-----+---------+-------+

4 rows in set (0.00 sec)

mysql> desc test1;

+-------+---------------------------------------+------+-----+---------+-------+

| Field | Type                                  | Null | Key | Default | Extra |

+-------+---------------------------------------+------+-----+---------+-------+

| id    | int(11)                               | YES  |     | NULL    |       |

| name  | char(11)                              | YES  |     | NULL    |       |

| sex   | enum('male','female')                 | YES  |     | NULL    |       |

| hobby | set('swiming','running','basketball') | YES  |     | NULL    |       |

+-------+---------------------------------------+------+-----+---------+-------+

4 rows in set (0.00 sec)

# 查看创建表的语句

mysql> show create table test1 \G;

*************************** 1. row ***************************

       Table: test1

Create Table: CREATE TABLE `test1` (

  `id` int(11) DEFAULT NULL,

  `name` char(11) DEFAULT NULL,

  `sex` enum('male','female') DEFAULT NULL,

  `hobby` set('swiming','running','basketball') DEFAULT NULL

) ENGINE=InnoDB DEFAULT CHARSET=utf8

1 row in set (0.00 sec)

2.删除表

语法:

DROP TABLE 表名;

注意：删表要谨慎

mysql> show tables;

+--------------------+

| Tables_in_python25 |

+--------------------+

| test1              |

| test2              |

| test3              |

| test4              |

+--------------------+

4 rows in set (0.00 sec)

mysql> drop table test1;

Query OK, 0 rows affected (0.01 sec)

mysql> drop table test2;

Query OK, 0 rows affected (0.01 sec)

mysql> show tables;

+--------------------+

| Tables_in_python25 |

+--------------------+

| test3              |

| test4              |

+--------------------+

2 rows in set (0.00 sec)

3.修改表

3.1 修改表名

语法

ALTER TABLE 表名 RENAME 新表名;

范例

mysql> show tables;

+--------------------+

| Tables_in_python25 |

+--------------------+

| test3              |

| test4              |

+--------------------+

2 rows in set (0.00 sec)

mysql> alter table test3 rename test1;

Query OK, 0 rows affected (0.02 sec)

mysql> show tables;

+--------------------+

| Tables_in_python25 |

+--------------------+

| test1              |

| test4              |

+--------------------+

2 rows in set (0.00 sec)

3.2 增加字段

语法

ALTER TABLE 表名 ADD 字段名数据类型[(宽度) 约束条件], ADD 字段名数据类型[(宽度) 约束条件];

范例

mysql> desc test1;

+-------+-----------------------+------+-----+---------+-------+

| Field | Type                  | Null | Key | Default | Extra |

+-------+-----------------------+------+-----+---------+-------+

| id    | int(11)               | YES  |     | NULL    |       |

| name  | char(10)              | YES  |     | NULL    |       |

| age   | int(11)               | YES  |     | NULL    |       |

| sex   | enum('male','female') | YES  |     | NULL    |       |

| phone | char(11)              | YES  |     | NULL    |       |

| job   | char(10)              | YES  |     | NULL    |       |

+-------+-----------------------+------+-----+---------+-------+

6 rows in set (0.01 sec)

# 增加hobby、home两个字段

mysql> alter table test1 add hobby set('football', 'running'), add home char(10);

Query OK, 0 rows affected (0.04 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test1;

+-------+---------------------------+------+-----+---------+-------+

| Field | Type                      | Null | Key | Default | Extra |

+-------+---------------------------+------+-----+---------+-------+

| id    | int(11)                   | YES  |     | NULL    |       |

| name  | char(10)                  | YES  |     | NULL    |       |

| age   | int(11)                   | YES  |     | NULL    |       |

| sex   | enum('male','female')     | YES  |     | NULL    |       |

| phone | char(11)                  | YES  |     | NULL    |       |

| job   | char(10)                  | YES  |     | NULL    |       |

| hobby | set('football','running') | YES  |     | NULL    |       |

| home  | char(10)                  | YES  |     | NULL    |       |

+-------+---------------------------+------+-----+---------+-------+

8 rows in set (0.00 sec)

3.3 删除字段

语法

ALTER TABLE 表名 DROP 字段名;

范例

mysql> desc test1;

+-------+-----------------------+------+-----+---------+-------+

| Field | Type                  | Null | Key | Default | Extra |

+-------+-----------------------+------+-----+---------+-------+

| id    | int(11)               | YES  |     | NULL    |       |

| name  | char(10)              | YES  |     | NULL    |       |

| age   | int(11)               | YES  |     | NULL    |       |

| sex   | enum('male','female') | YES  |     | NULL    |       |

| phone | char(11)              | YES  |     | NULL    |       |

| job   | char(10)              | YES  |     | NULL    |       |

+-------+-----------------------+------+-----+---------+-------+

6 rows in set (0.01 sec)

# 删除hobby、home字段

mysql> alter table test1 add hobby set('football', 'running'), add home char(10);

Query OK, 0 rows affected (0.04 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test1;

+-------+---------------------------+------+-----+---------+-------+

| Field | Type                      | Null | Key | Default | Extra |

+-------+---------------------------+------+-----+---------+-------+

| id    | int(11)                   | YES  |     | NULL    |       |

| name  | char(10)                  | YES  |     | NULL    |       |

| age   | int(11)                   | YES  |     | NULL    |       |

| sex   | enum('male','female')     | YES  |     | NULL    |       |

| phone | char(11)                  | YES  |     | NULL    |       |

| job   | char(10)                  | YES  |     | NULL    |       |

| hobby | set('football','running') | YES  |     | NULL    |       |

| home  | char(10)                  | YES  |     | NULL    |       |

+-------+---------------------------+------+-----+---------+-------+

8 rows in set (0.00 sec)

3.4 修改字段

语法

ALTER TABLE 表名 MODIFY 字段名数据类型[(宽度) 约束条件];

ALTER TABLE 表名 CHANGE 旧字段名新字段名旧数据类型[(宽度) 约束条件];

ALTER TABLE 表名 CHANGE 旧字段名新字段名新数据类型[(宽度) 约束条件];

范例

mysql> desc test1;

+-------+-----------------------+------+-----+---------+-------+

| Field | Type                  | Null | Key | Default | Extra |

+-------+-----------------------+------+-----+---------+-------+

| id    | int(11)               | YES  |     | NULL    |       |

| name  | char(10)              | YES  |     | NULL    |       |

| age   | int(11)               | YES  |     | NULL    |       |

| sex   | enum('male','female') | YES  |     | NULL    |       |

| phone | char(11)              | YES  |     | NULL    |       |

| job   | char(10)              | YES  |     | NULL    |       |

+-------+-----------------------+------+-----+---------+-------+

6 rows in set (0.00 sec)

# 修改job字段的数据类型

mysql> alter table test1 modify job varchar(11);

Query OK, 0 rows affected (0.06 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test1;

+-------+-----------------------+------+-----+---------+-------+

| Field | Type                  | Null | Key | Default | Extra |

+-------+-----------------------+------+-----+---------+-------+

| id    | int(11)               | YES  |     | NULL    |       |

| name  | char(10)              | YES  |     | NULL    |       |

| age   | int(11)               | YES  |     | NULL    |       |

| sex   | enum('male','female') | YES  |     | NULL    |       |

| phone | char(11)              | YES  |     | NULL    |       |

| job   | varchar(11)           | YES  |     | NULL    |       |

+-------+-----------------------+------+-----+---------+-------+

6 rows in set (0.01 sec)

# 修改job字段为hobby字段

mysql> alter table test1 change job hobby varchar(11);

Query OK, 0 rows affected (0.02 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test1;

+-------+-----------------------+------+-----+---------+-------+

| Field | Type                  | Null | Key | Default | Extra |

+-------+-----------------------+------+-----+---------+-------+

| id    | int(11)               | YES  |     | NULL    |       |

| name  | char(10)              | YES  |     | NULL    |       |

| age   | int(11)                   | YES  |     | NULL    |       |

| sex   | enum('male','female') | YES  |     | NULL    |       |

| phone | char(11)              | YES  |     | NULL    |       |

| hobby | varchar(11)           | YES  |     | NULL    |       |

+-------+-----------------------+------+-----+---------+-------+

6 rows in set (0.00 sec)

# 修改hobby字段为job字段，且数据类型改为char

mysql> alter table test1 change hobby job char(11);

Query OK, 0 rows affected (0.06 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test1;

+-------+-----------------------+------+-----+---------+-------+

| Field | Type                  | Null | Key | Default | Extra |

+-------+-----------------------+------+-----+---------+-------+

| id    | int(11)               | YES  |     | NULL    |       |

| name  | char(10)              | YES  |     | NULL    |       |

| age   | int(11)               | YES  |     | NULL    |       |

| sex   | enum('male','female') | YES  |     | NULL    |       |

| phone | char(11)              | YES  |     | NULL    |       |

| job   | char(11)              | YES  |     | NULL    |       |

+-------+-----------------------+------+-----+---------+-------+

6 rows in set (0.01 sec)

3.5 修改字段排列顺序、在增加的时候指定字段位置

语法

ALTER TABLE 表名 ADD 字段名数据类型 [(宽度) 约束条件] FIRST;

ALTER TABLE 表名 ADD 字段名数据类型 [(宽度) 约束条件] AFTER 字段名;

ALTER TABLE 表名 CHANGE 字段名旧字段名新字段名新数据类型 [(宽度) 约束条件] FIRST;

ALTER TABLE 表名 MODIFY 字段名数据类型 [(宽度) 约束条件] AFTER 字段名;

范例

mysql> desc test1;

+-------+-----------------------+------+-----+---------+-------+

| Field | Type                  | Null | Key | Default | Extra |

+-------+-----------------------+------+-----+---------+-------+

| id    | int(11)               | YES  |     | NULL    |       |

| name  | char(10)              | YES  |     | NULL    |       |

| age   | int(11)               | YES  |     | NULL    |       |

| sex   | enum('male','female') | YES  |     | NULL    |       |

| phone | char(11)              | YES  |     | NULL    |       |

| job   | char(11)              | YES  |     | NULL    |       |

+-------+-----------------------+------+-----+---------+-------+

6 rows in set (0.01 sec)

# 在表的开头添加hobby字段

mysql> alter table test1 add hobby char(10) first;

Query OK, 0 rows affected (0.05 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test1;

+-------+-----------------------+------+-----+---------+-------+

| Field | Type                  | Null | Key | Default | Extra |

+-------+-----------------------+------+-----+---------+-------+

| hobby | char(10)              | YES  |     | NULL    |       |

| id    | int(11)               | YES  |     | NULL    |       |

| name  | char(10)              | YES  |     | NULL    |       |

| age   | int(11)               | YES  |     | NULL    |       |

| sex   | enum('male','female') | YES  |     | NULL    |       |

| phone | char(11)              | YES  |     | NULL    |       |

| job   | char(11)              | YES  |     | NULL    |       |

+-------+-----------------------+------+-----+---------+-------+

7 rows in set (0.00 sec)

# 在job字段后面添加salary字段

mysql> alter table test1 add salary int after job;

Query OK, 0 rows affected (0.05 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test1;

+--------+-----------------------+------+-----+---------+-------+

| Field  | Type                  | Null | Key | Default | Extra |

+--------+-----------------------+------+-----+---------+-------+

| hobby  | char(10)              | YES  |     | NULL    |       |

| id     | int(11)               | YES  |     | NULL    |       |

| name   | char(10)              | YES  |     | NULL    |       |

| age    | int(11)               | YES  |     | NULL    |       |

| sex    | enum('male','female') | YES  |     | NULL    |       |

| phone  | char(11)              | YES  |     | NULL    |       |

| job    | char(11)              | YES  |     | NULL    |       |

| salary | int(11)               | YES  |     | NULL    |       |

+--------+-----------------------+------+-----+---------+-------+

8 rows in set (0.00 sec)

# 修改hobby字段名为aihao

mysql> alter table test1 change hobby aihao char(10) first;

Query OK, 0 rows affected (0.02 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test1;

+--------+-----------------------+------+-----+---------+-------+

| Field  | Type                  | Null | Key | Default | Extra |

+--------+-----------------------+------+-----+---------+-------+

| aihao  | char(10)              | YES  |     | NULL    |       |

| id     | int(11)               | YES  |     | NULL    |       |

| name   | char(10)              | YES  |     | NULL    |       |

| age    | int(11)               | YES  |     | NULL    |       |

| sex    | enum('male','female') | YES  |     | NULL    |       |

| phone  | char(11)              | YES  |     | NULL    |       |

| job    | char(11)              | YES  |     | NULL    |       |

| salary | int(11)               | YES  |     | NULL    |       |

+--------+-----------------------+------+-----+---------+-------+

8 rows in set (0.00 sec)

# 把aihao字段放到salary字段后面

mysql> alter table test1 modify aihao char(10) after salary;

Query OK, 0 rows affected (0.04 sec)

Records: 0  Duplicates: 0  Warnings: 0

mysql> desc test1;

+--------+-----------------------+------+-----+---------+-------+

| Field  | Type                  | Null | Key | Default | Extra |

+--------+-----------------------+------+-----+---------+-------+

| id     | int(11)               | YES  |     | NULL    |       |

| name   | char(10)              | YES  |     | NULL    |       |

| age    | int(11)               | YES  |     | NULL    |       |

| sex    | enum('male','female') | YES  |     | NULL    |       |

| phone  | char(11)              | YES  |     | NULL    |       |

| job    | char(11)              | YES  |     | NULL    |       |

| salary | int(11)               | YES  |     | NULL    |       |

| aihao  | char(10)              | YES  |     | NULL    |       |

+--------+-----------------------+------+-----+---------+-------+

8 rows in set (0.00 sec)

4.数据操作

创建表

# 创建语句

create table teacher(

id int primary key,

name char(10) not null,

age int,

hire_date datetime,

sex enum('male', 'female') not null default 'male',

phone char(11) unique,

salary float(8, 2),

hobby set('running', 'football', 'basketball'),

comment varchar(255)

);

# 查看表结构

mysql> desc teacher;

+-----------+----------------------------------------+------+-----+---------+-------+

| Field     | Type                                   | Null | Key | Default | Extra |

+-----------+----------------------------------------+------+-----+---------+-------+

| id        | int(11)                                | NO   | PRI | NULL    |       |

| name      | char(10)                               | NO   |     | NULL    |       |

| age       | int(11)                                | YES  |     | NULL    |       |

| hire_date | datetime                               | YES  |     | NULL    |       |

| sex       | enum('male','female')                  | NO   |     | male    |       |

| phone     | char(11)                               | YES  | UNI | NULL    |       |

| salary    | float(8,2)                             | YES  |     | NULL    |       |

| hobby     | set('running','football','basketball') | YES  |     | NULL    |       |

| comment   | varchar(255)                           | YES  |     | NULL    |       |

+-----------+----------------------------------------+------+-----+---------+-------+

9 rows in set (0.00 sec)

4.1 插入数据

语法

插入单行数据，

INSERT INTO 表名 (字段1，字段2，字段3...) value (值1, 值2, 值3);

如果不添加字段名称，插入的数据需要与表里的字段一一对应

INSERT INTO 表名 value (值1, 值2, 值3);

插入多行数据

INSERT INTO 表名 values (值1, 值2, 值3),(值1, 值2, 值3),(值1, 值2, 值3);

范例

#  插入单条数据，注意float类型会进行四舍五入

mysql> insert into teacher (id, name, hobby) value (1, 'zhangsan', 'running');

Query OK, 1 row affected (0.42 sec)

mysql> select * from teacher;

+----+----------+------+-----------+------+-------+--------+---------+---------+

| id | name     | age  | hire_date | sex  | phone | salary | hobby   | comment |

+----+----------+------+-----------+------+-------+--------+---------+---------+

|  1 | zhangsan | NULL | NULL      | male | NULL  |   NULL | running | NULL    |

+----+----------+------+-----------+------+-------+--------+---------+---------+

1 row in set (0.00 sec)

mysql> insert into teacher value (2, 'lisi', 30, '2017-10-20', 'male', '13069948980', 2000, 'basketball', 'haha');

Query OK, 1 row affected (0.15 sec)

mysql> select * from teacher;

+----+----------+------+---------------------+------+-------------+---------+------------+---------+

| id | name     | age  | hire_date           | sex  | phone       | salary  | hobby      | comment |

+----+----------+------+---------------------+------+-------------+---------+------------+---------+

|  1 | zhangsan | NULL | NULL                | male | NULL        |    NULL | running    | NULL    |

|  2 | lisi     |   30 | 2017-10-20 00:00:00 | male | 13069948980 | 2000.00 | basketball | haha    |

+----+----------+------+---------------------+------+-------------+---------+------------+---------+

2 rows in set (0.03 sec)

# 插入多条数据

mysql> insert into teacher values (3, 'wangwu', 28, '2016-11-20', 'male', '1382333333', 20000, 'football', 'wowo'),

    ->  (4, 'xiaoli', 28, '2015-11-20', 'female', '13823333333', 20000, 'football', 'wowo');

Query OK, 2 rows affected (0.40 sec)

Records: 2  Duplicates: 0  Warnings: 0

mysql> select * from teacher;

+----+----------+------+---------------------+--------+-------------+----------+------------+---------+

| id | name     | age  | hire_date           | sex    | phone       | salary   | hobby      | comment |

+----+----------+------+---------------------+--------+-------------+----------+------------+---------+

|  1 | zhangsan | NULL | NULL                | male   | NULL        |     NULL | running    | NULL    |

|  2 | lisi     |   30 | 2017-10-20 00:00:00 | male   | 13069948980 |  2000.00 | basketball | haha    |

|  3 | wangwu   |   28 | 2016-11-20 00:00:00 | male   | 1382333333  | 20000.00 | football   | wowo    |

|  4 | xiaoli   |   28 | 2015-11-20 00:00:00 | female | 13823333333 | 20000.00 | football   | wowo    |

+----+----------+------+---------------------+--------+-------------+----------+------------+---------+

4 rows in set (0.00 sec)

4.2 删除数据

语法

DELETE FROM 表名 WHERE ....;

范例

mysql> select * from teacher;

+----+----------+------+---------------------+--------+-------------+----------+------------+---------+

| id | name     | age  | hire_date           | sex    | phone       | salary   | hobby      | comment |

+----+----------+------+---------------------+--------+-------------+----------+------------+---------+

|  1 | zhangsan | NULL | NULL                | male   | NULL        |     NULL | running    | NULL    |

|  2 | lisi     |   30 | 2017-10-20 00:00:00 | male   | 13069948980 |  2000.00 | basketball | haha    |

|  3 | wangwu   |   28 | 2016-11-20 00:00:00 | male   | 1382333333  | 20000.00 | football   | wowo    |

|  4 | xiaoli   |   28 | 2015-11-20 00:00:00 | female | 13823333333 | 20000.00 | football   | wowo    |

+----+----------+------+---------------------+--------+-------------+----------+------------+---------+

4 rows in set (0.00 sec)

mysql> delete from teacher where id=1;

Query OK, 1 row affected (0.48 sec)

mysql> select * from teacher;

+----+--------+------+---------------------+--------+-------------+----------+------------+---------+

| id | name   | age  | hire_date           | sex    | phone       | salary   | hobby      | comment |

+----+--------+------+---------------------+--------+-------------+----------+------------+---------+

|  2 | lisi   |   30 | 2017-10-20 00:00:00 | male   | 13069948980 |  2000.00 | basketball | haha    |

|  3 | wangwu |   28 | 2016-11-20 00:00:00 | male   | 1382333333  | 20000.00 | football   | wowo    |

|  4 | xiaoli |   28 | 2015-11-20 00:00:00 | female | 13823333333 | 20000.00 | football   | wowo    |

+----+--------+------+---------------------+--------+-------------+----------+------------+---------+

3 rows in set (0.00 sec)

4.3 更新数据

语法

UPDATE 表名 SET 字段1=值1, 字段2=值2 WHERE ...;

范例

mysql> select * from teacher;

+----+--------+------+---------------------+--------+-------------+----------+------------+---------+

| id | name   | age  | hire_date           | sex    | phone       | salary   | hobby      | comment |

+----+--------+------+---------------------+--------+-------------+----------+------------+---------+

|  2 | lisi   |   30 | 2017-10-20 00:00:00 | male   | 13069948980 |  2000.00 | basketball | haha    |

|  3 | wangwu |   28 | 2016-11-20 00:00:00 | male   | 1382333333  | 20000.00 | football   | wowo    |

|  4 | xiaoli |   28 | 2015-11-20 00:00:00 | female | 13823333333 | 20000.00 | football   | wowo    |

+----+--------+------+---------------------+--------+-------------+----------+------------+---------+

3 rows in set (0.00 sec)

mysql> update teacher set age=40 where id=2;

Query OK, 1 row affected (0.46 sec)

Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from teacher;

+----+--------+------+---------------------+--------+-------------+----------+------------+---------+

| id | name   | age  | hire_date           | sex    | phone       | salary   | hobby      | comment |

+----+--------+------+---------------------+--------+-------------+----------+------------+---------+

|  2 | lisi   |   40 | 2017-10-20 00:00:00 | male   | 13069948980 |  2000.00 | basketball | haha    |

|  3 | wangwu |   28 | 2016-11-20 00:00:00 | male   | 1382333333  | 20000.00 | football   | wowo    |

|  4 | xiaoli |   28 | 2015-11-20 00:00:00 | female | 13823333333 | 20000.00 | football   | wowo    |

+----+--------+------+---------------------+--------+-------------+----------+------------+---------+

3 rows in set (0.00 sec)

4.4 查询数据

单表查询

多表查询

03-MySQL表操作的更多相关文章

Python 3 mysql 表操作
Python 3 mysql 表操作表相当于文件,表中的一条记录就相当于文件的一行内容,不同的是,表中的一条记录有对应的标题,称为表的字段 id,name,qq,age称为字段,其余的,一行内容称为 ...
8.3 mysql 表操作
库操作一系统数据库 information_schema: 虚拟库,不占用磁盘空间,存储的是数据库启动后的一些参数,如用户表信息.列信息.权限信息.字符信息等 performance_sch ...
数据库 -- mysql表操作
一,存储引擎介绍存储引擎即表类型,mysql根据不同的表类型会有不同的处理机制详见:https://www.cnblogs.com/peng104/p/9751738.html 二,表介绍表相当 ...
MySQL表操作及数据操作
表操作表相当于一个文件,其形式与现实中的表格相同.表中的每条记录都有相应的字段,字段就类似于表格的表头. 表操作详细: #对表进行操作(文件) #首先要切换到指定库(即文件夹)下:use db1; ...
细说MySQL表操作
目录语法查看表结构查看所有的表删除表查看创建表的语句修改表的字符集和校验规则修改表名在表中添加新字段修改表的字段名修改表中字段的属性删除表中的某个字段设置某个字段为主键把某个 ...
mysql表操作与权限操作
修改表ALTER TABLE 语法: . 修改表名 ALTER TABLE 表名 RENAME 新表名; . 增加字段 ALTER TABLE 表名 ADD 字段名数据类型 [完整性约束条件…], ...
mysql数据库从删库到跑路之mysql表操作
表介绍表相当于文件,表中的一条记录就相当于文件的一行内容,不同的是,表中的一条记录有对应的标题,称为表的字段 id,name,qq,age称为字段,其余的,一行内容称为一条记录内容: 1 创建表 ...
MySQL 表操作（Day40）
阅读目录一.表介绍二.创建表三.查看表四.修改表五.删除表六.操作表中的记录一.表介绍表相当于文件,表中的一条记录就相当于文件的一行内容,不同的是,表中的一条记录有对应的标题,则称为表 ...
Mysql表操作
查看表结构: 可以使用describe或show create table语句查看表的结构: describe表名; Show create table 表名; 修改表名: Alter table 旧 ...
mysql 表操作
创建表简单的方式 CREATE TABLE person ( number INT(11), name VARCHAR(255), birthday DATE ); 或者是 CREATE TABLE ...

随机推荐

将Python 程序打包成 .exe格式入门
PyInstaller PyInstaller 是一个十分有用的第三方库,可以用来打包 python 应用程序,打包完的程序就可以在没有安装 Python 解释器的机器上运行了. 它能够在 Windo ...
[Vue] karme/jasmine/webpack/vue搭建测试环境
karma 和 jasmine karma 是 google 开源的一个基于 Node.js 的 JavaScript 前端测试运行框架,前身叫 Testacular. jasmine 是一个 jav ...
PMBook - 6.项目进度管理
6.3 排列活动顺序 6.3.1 排列活动顺序:输入 6.3.1.1 项目管理计划 6.3.1.2 项目文件 6.3.1.3 事业环境因素 6.3.1.4 组织过程资产 6.3.2 排列活动顺序: ...
ASP.NET Core Web API 版本控制
在nuget.org上,您可以找到 Microsoft.AspNetCore.Mvc.Versioning包,它提供了有关如何对Web API端点进行版本化的更多选项.这个包的好处是允许你直接在控制 ...
带着新人简单看看servlet到springmvc
好久都没有写博客了,不是因为自己懒了,而是总感觉自己知道的只是太少了,每次想写博客的时候都不知道怎么下手,不过最近看到一篇博客说的是springmvc,给了我比较大的兴趣,感觉一下子对整个spring ...
Python3+unitest自动化测试初探（下篇）
目录 9.用例结果校验 10.跳过用例 11.Test Discovery 12.加载用例 unittest官方文档本篇随笔承接: Python3+unitest自动化测试初探(中篇) Python ...
C++与Lua交互之配置&交互原理&示例
|Lua 简介 Lua 是一种轻量小巧的脚本语言,也是号称性能最高的脚本语言,它用C语言编写并以源代码形式开放. 某些程序常常需要修改内容,而修改的内容不仅仅是数据,更要修改很多函数的行为. 而修改函 ...
SQLServer低版本附加高版本的数据库常用处理方法
SqlServer低版本数据库不能直接还原或附加Sql高版本数据库或备份文件,我们常用DTS互导的方式,如果不同版本数据库不可访问,可以使用高版本数据库的DTS导出整个库的相应低版本建库脚本与数据,然 ...
[翻译]Mock 在 Python 中的使用介绍
目录 Mock 在 Python 中的使用介绍原文链接与说明恐惧系统调用一个简单的删除函数使用 Mock 重构潜在陷阱向 'rm' 中加入验证将文件删除作为服务方法 1:模拟实例的方法 ...
cocos creator主程入门教程（六）—— 消息分发
五邑隐侠,本名关健昌,10年游戏生涯,现隐居五邑.本系列文章以TypeScript为介绍语言. 本篇开始介绍游戏业务架构相关的内容.在游戏业务层,所有需要隔离的系统和模块间通信都可以通过消息分发解耦. ...

03-MySQL表操作