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  • MySQL数据库

    【注" "】命名

    使用命令窗口链接MySQL数据库:

      Window+R打开运行输入cmd;

      mysql -u用户名 -p  回车后填写密码; 【注意:空格区分】

    数据库服务器、数据库和表的关系:

      所谓数据库服务器, 是指在机器上装了一个数据库管理程序,这个管理程序可以管理多个数据库,一般开发人员会针对每一个应用创建一个数据库。

      为保存应用中实体的数据,一般会在数据库创建多个表,以保存程序中实体的数据。 

    数据库的管理:

      查询所有数据库 show databases;

    mysql> show databases;
    +--------------------+
    | Database           |
    +--------------------+
    | information_schema |
    | java0512           |
    | mysb1              |
    | mysql              |
    | performance_schema |
    | test               |
    +--------------------+
    6 rows in set (0.00 sec)

      创建数据库 create database " "    " " 自定义名称;

           character set " "    指定数据库采用的字符集;

    mysql> create database mysb2 character set utf8;
    Query OK, 1 row affected (0.00 sec)

      显示数据库创建:show create database " ";

    mysql> show create database mysb2;
    +----------+----------------------------------------------------------------+
    | Database | Create Database                                                |
    +----------+----------------------------------------------------------------+
    | mysb2    | CREATE DATABASE `mysb2` /*!40100 DEFAULT CHARACTER SET utf8 */ |
    +----------+----------------------------------------------------------------+
    1 row in set (0.00 sec)

      数据库删除:drop database " ";

    mysql> drop database mysb2;
    Query OK, 0 rows affected (0.00 sec)

      修改数据库:alter database " " character set utf8;

    mysql> alter database mysb1 character set utf8;
    Query OK, 1 row affected (0.00 sec)

    表管理:

      选择数据库: use " ";

      查看所有表:show tables;

    mysql> use mysb1;
    Database changed
    mysql> show tables;
    +-----------------+
    | Tables_in_mysb1 |
    +-----------------+
    | yuangong        |
    +-----------------+
    1 row in set (0.00 sec)

      创建表:create table " "(指定数据类型);  创建表前,要先使用use  语句使用库

    mysql> create table student(id varchar(20),sage int);
    Query OK, 0 rows affected (0.00 sec)

      查看表结构:desc " ";

    mysql> desc student;
    +-------+-------------+------+-----+---------+-------+
    | Field | Type        | Null | Key | Default | Extra |
    +-------+-------------+------+-----+---------+-------+
    | id    | varchar(20) | YES  |     | NULL    |       |
    | sage  | int(11)     | YES  |     | NULL    |       |
    +-------+-------------+------+-----+---------+-------+
    2 rows in set (0.00 sec)

      删除表:drop table " ";

    mysql> drop table student;
    Query OK, 0 rows affected (0.01 sec)

      修改表:

        1.)添加字段 alert table " " add column " " varchar();

    mysql> alter table student add column sgender varchar(20);
    Query OK, 0 rows affected (0.01 sec)
    Records: 0  Duplicates: 0  Warnings: 0

        2.)删除字段alter table " " drop column " ";

    mysql> alter table student drop column sgender;
    Query OK, 0 rows affected (0.01 sec)
    Records: 0  Duplicates: 0  Warnings: 0

        3.)修改字段类型 alter table " " modify column id varchar(50);

    mysql> alter table student modify column id varchar(50);
    Query OK, 0 rows affected (0.01 sec)
    Records: 0  Duplicates: 0  Warnings: 0

        4.)修改字段昵称 alter table " " change column id name varchar(50);

    mysql> alter table student change column id name varchar(50);
    Query OK, 0 rows affected (0.01 sec)
    Records: 0  Duplicates: 0  Warnings: 0

        5.)修改表名称 alter table " " rename to teacher;

    mysql> alter table student rename to teacher;
    Query OK, 0 rows affected (0.01 sec)

      

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  • 原文地址:https://www.cnblogs.com/wode007/p/13141538.html
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