-
端口：3306
-
密码：. . . . .
-
什么是表？ 数据库的基本组成单元，所有的数据都以表格的形式组织，目的是可读性强。
一个表包括行和列：
行：被称为数据/记录（data）
列：字段（column）
每一个字段应该包括哪些属性？
字段名，数据类型，相关的约束
- SQL语句，包括增删改查，怎么分类？
DQL（数据查询语言）:查询语句，凡是select语句都是DQL
DML（数据操作语言）：insert，delete，update，对表当中的数据进行增删改
DDL（数据定义语言）:creat, drop, alter 对表结构的增删改
TCL（事务控制语言）：commit提交事务，rollback回滚事务
DCL（数据控制语言）：grant授权，revoke撤销权限等
- 导入数据
- 登录-dos命令窗口 mysql -u root -p 密码
- 查看有哪些数据库：show databases;（mysql命令，不是SQL语句）
+--------------------+
| Database |
+--------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
+--------------------+
-
创建自己的数据库bjpowernode : create database bjpowernode;
-
使用数据库：use bjpowernode;
-
**显示当前数据库里有哪些表格：mysql> show tables; **
+---------------------------+
| Tables_in_mysql |
+---------------------------+
| columns_priv |
| db |
| engine_cost |
| event |
| func |
| general_log |
| gtid_executed |
| help_category |
| help_keyword |
| help_relation |
| help_topic |
| innodb_index_stats |
| innodb_table_stats |
| ndb_binlog_index |
| plugin |
| proc |
| procs_priv |
| proxies_priv |
| server_cost |
| servers |
| slave_master_info |
| slave_relay_log_info |
| slave_worker_info |
| slow_log |
| tables_priv |
| time_zone |
| time_zone_leap_second |
| time_zone_name |
| time_zone_transition |
| time_zone_transition_type |
| user |
+---------------------------+
6.初始化数据：source +(文件地址 .sql)
当一个文件为sql结尾，这样的文件叫做“sql脚本”，什么是sql脚本？
当一个文件的拓展名是.sql，并且该文件中编写了大量的sql语句，成为sql脚本可以用source打开初始化
-
删除数据库show database bjpowernode；
-
查看表结构:desc+表名字
+-----------------------+
| Tables_in_bjpowernode |
+-----------------------+
| dept | 部门表
| emp |员工表
| salgrade |工资等级表
+-----------------------+
mysql> desc dept;
+--------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| DEPTNO | int(2) | NO | PRI | NULL | |部门编号
| DNAME | varchar(14) | YES | | NULL | |名称
| LOC | varchar(13) | YES | | NULL | |位置
+--------+-------------+------+-----+---------+-------+
mysql> desc emp;
+----------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| EMPNO | int(4) | NO | PRI | NULL | |员工编号
| ENAME | varchar(10) | YES | | NULL | |姓名
| JOB | varchar(9) | YES | | NULL | |工作岗位
| MGR | int(4) | YES | | NULL | |上级领导编号
| HIREDATE | date | YES | | NULL | |入职日期
| SAL | double(7,2) | YES | | NULL | |月薪
| COMM | double(7,2) | YES | | NULL | |补助
| DEPTNO | int(2) | YES | | NULL | |部门编号
+----------+-------------+------+-----+---------+-------+
mysql> desc salgrade;
+-------+---------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+---------+------+-----+---------+-------+
| GRADE | int(11) | YES | | NULL | |等级
| LOSAL | int(11) | YES | | NULL | |最低
| HISAL | int(11) | YES | | NULL | |最高
+-------+---------+------+-----+---------+-------+
9. 表格中的数据？（真正的SQL语句）
mysql> select * from dept;
+--------+------------+----------+
| DEPTNO | DNAME | LOC |
+--------+------------+----------+
| 10 | ACCOUNTING | NEW YORK |
| 20 | RESEARCH | DALLAS |
| 30 | SALES | CHICAGO |
| 40 | OPERATIONS | BOSTON |
+--------+------------+----------+
mysql> select * from emp;
+-------+--------+-----------+------+------------+---------+---------+--------+
| EMPNO | ENAME | JOB | MGR | HIREDATE | SAL | COMM | DEPTNO |
+-------+--------+-----------+------+------------+---------+---------+--------+
| 7369 | SMITH | CLERK | 7902 | 1980-12-17 | 800.00 | NULL | 20 |
| 7499 | ALLEN | SALESMAN | 7698 | 1981-02-20 | 1600.00 | 300.00 | 30 |
| 7521 | WARD | SALESMAN | 7698 | 1981-02-22 | 1250.00 | 500.00 | 30 |
| 7566 | JONES | MANAGER | 7839 | 1981-04-02 | 2975.00 | NULL | 20 |
| 7654 | MARTIN | SALESMAN | 7698 | 1981-09-28 | 1250.00 | 1400.00 | 30 |
| 7698 | BLAKE | MANAGER | 7839 | 1981-05-01 | 2850.00 | NULL | 30 |
| 7782 | CLARK | MANAGER | 7839 | 1981-06-09 | 2450.00 | NULL | 10 |
| 7788 | SCOTT | ANALYST | 7566 | 1987-04-19 | 3000.00 | NULL | 20 |
| 7839 | KING | PRESIDENT | NULL | 1981-11-17 | 5000.00 | NULL | 10 |
| 7844 | TURNER | SALESMAN | 7698 | 1981-09-08 | 1500.00 | 0.00 | 30 |
| 7876 | ADAMS | CLERK | 7788 | 1987-05-23 | 1100.00 | NULL | 20 |
| 7900 | JAMES | CLERK | 7698 | 1981-12-03 | 950.00 | NULL | 30 |
| 7902 | FORD | ANALYST | 7566 | 1981-12-03 | 3000.00 | NULL | 20 |
| 7934 | MILLER | CLERK | 7782 | 1982-01-23 | 1300.00 | NULL | 10 |
+-------+--------+-----------+------+------------+---------+---------+--------+
mysql> select * from salgrade;
+-------+-------+-------+
| GRADE | LOSAL | HISAL |
+-------+-------+-------+
| 1 | 700 | 1200 |
| 2 | 1201 | 1400 |
| 3 | 1401 | 2000 |
| 4 | 2001 | 3000 |
| 5 | 3001 | 9999 |
+-------+-------+-------+
10.常用命令：
mysql> select database(); 查看正在使用哪个数据库
+-------------+
| database() |
+-------------+
| bjpowernode |
+-------------+
1 row in set (0.00 sec)
mysql> select version();查看数据库版本号
+------------+
| version() |
+------------+
| 5.7.37-log |
+------------+
\c 结束一个语句
exit 退出
