• 通过disql连接数据库。
• 进入目录DM8/bin目录下[dmdba@localhost /]$ cd DM8/bin
• 启动disql工具[dmdba@localhost bin]$ ./disql

输入用户名SYSDBA,密码SYSDBA,默认连接端口为5236

• 查看数据库状态SQL>  select INSTANCE_NAME,STATUS$ from v$instance;
• 从open状态改为配置模式SQL> alter database mount;
• 从配置模式改为open状态SQL> alter database open;
• 从open状态改为挂起状态SQL> alter database suspend;
• 从挂起状态改为open状态SQL> alter database open;
• 数据库直接关闭SQL> shutdown normal;
• 服务重启

• 服务状态查看[root@localhost system]# systemctl status DmServiceDMSERVER
• 查看日志文件大小SQL> select path,rlog_size/1024/1024 from v$rlogfile;
• 修改日志文件大小：注意所有的日志文件必须同时修改，并且大小一样。达梦要求   至少有两个日志文件。

     SQL> alter database resize logfile '/DM8/data/DAMENG/DAMENG01.log' to 500;

     SQL> alter database resize logfile '/DM8/data/DAMENG/DAMENG02.log' to 500;

• 控制文件备份位置查询SQL> select para_name,para_value from v$dm_ini where para_name='CTL_PATH';
• 共享内存总容量查询SQL> select para_name,para_value from v$dm_ini where para_name='MEMORY_TARGET';
• 共享内存总容量大小修改SQL>  sp_set_para_value(1,'MEMORY_TARGET',1024);
• 公共池查询SQL> select para_name,para_value,para_type from v$dm_ini where para_name='MEMORY_POOL';
• 数据缓冲池查询select para_name,para_value,para_type from v$dm_ini where para_name='BUFFER';
• 字典缓冲区查询SQL> select para_name,para_value,para_type from v$dm_ini where para_name='DICT_BUF_SIZE';
• SQL缓冲区查询SQL> select para_name,para_value,para_type from v$dm_ini where para_name='CACHE_POOL_SIZE';
• 表空间信息查询SQL> select tablespace_name from dba_tablespaces;
• 页大小查询SQL> select page; 注意初始大小必须是页的4096倍。
• 表空间初始大小计算SQL>  select 4096*8/1024;
• 表空间创建SQL> create tablespace tbs datafile '/DM8/data/DAMENG/tbs.dbf' size 32 autoextend on maxsize 1024;
• 一个表空间下有两个数据文件SQL> create tablespace tbs1 datafile '/DM8/data/DAMENG/tbs1_1.dbf' size 32 autoextend on next 1 maxsize 1024,'/DM8/data/DAMENG/tbs1_2.dbf' size 32 autoextend on next 1 maxsize 1024;
• 表空间状态查询SQL>  select tablespace_name,status from dba_tablespaces;
• 临时表空间信息查询SQL> select para_name,para_value from v$dm_ini where para_name like 'TEMP%';
• 修改临时表空间大小SQL>  sp_set_para_value(2,'TEMP_SIZE',100); 修改之后需要重启服务才会生效。
• 删除表空间SQL> drop tablespace tbs1;
• 用户信息查询SQL> select username from dba_users;
• 新建用户SQL> create user user1 identified by "dameng123" default tablespace tbs;
• 查询用户默认权限SQL> select grantee,granted_role from dba_role_privs where grantee='USER1';
• 查询角色权限SQL> select grantee,privilege from dba_sys_privs where grantee='PUBLIC';
• 给用户授权SQL>  grant create table to user1;
• 撤销授权SQL>  revoke create table from user1;
• 创建角色SQL>  create role r1;
• 给角色授权SQL> grant create table to r1;
• 把角色分配给用户SQL> grant r1 to user1;
• 修改用户密码SQL>  alter user user1 identified by "dameng1234";
• 锁定用户SQL>  alter user user1 account lock;
• 解锁用户SQL>  alter user user2 account unlock;
• 级联删除用户SQL>drop user user1 cascade;
• 创建表SQL> create table t1 (id int not null);
• 插入表数据SQL> insert into t1 values (null);
• 查看表创建语句SQL> sp_tabledef('USER1','T1');
• 删除表SQL>drop table test;
• 视图创建SQL> create view v1 as select * from dmhr.city;
• 视图修改重建SQL> create or replace view v1 as select city_name from dmhr.city;
• 视图删除SQL>  drop view v1;
• 新建表SQL> create table emp as select * from dmhr.employee;
• 在emp表上新建索引SQL>  create index ind_emp on emp(employee_id);
• 在线重建索引SQL> alter index ind_emp rebuild online;
• 删除索引SQL>  drop index ind_emp;
• DML数据管理语句查询.insert、delete、update、select

 --查询名字只有两个字的员工信息

 select employee_name from dmhr.employee where

employee_name like '__';

--获得工资在19000到30000之间的员工信息。

select employee_name,salary from dmhr.employee

where salary between 19000 and  30000;

--按照薪水排降序

select employee_name,salary from dmhr.employee

order by 2 desc;

获取工资总和大于200000的部门信息。

select department_id,sum(salary) from

dmhr.employee group by department_id having

sum(salary)>200000;

--交叉链接

select * from dmhr.employee cross join dmhr.department;

--自然链接

select employee_name,department_name from employee natural join department;

--using字句，相当于on

select employee_name,department_name from employee join department using (department_id);

--on字句

select employee_name,department_name from

employee e join department d

on e.department_id=d.department_id;

--hash join链接

select employee_name,department_name from

employee e inner hash join department d on e.department_id=d.department_id;

--自连接

select e.employee_name,m.employee_name from

employee e join employee m on e.manager_id=m.employee_id;

--左外连接

select e.employee_name,d.department_name from

employee e left join department d on e.department_id=d.department_id;

--右外连接

select e.employee_name,d.department_name from

employee e right join department d on e.department_id=d.department_id;

--全外连接

select e.employee_name,d.department_name from

employee e full join department d on e.department_id=d.department_id;