Oracle-常用语句

--管理语句
--当前用户权限
select * from user_role_privs;
--当前用户表空间
select username,default_tablespace from user_users;
--查看哪些用户有sysdba或sysoper系统权限(查询时需要相应权限)s
select * from V$PWFILE_USERS;


--查询语句
SELECT TO_CHAR(SYSDATE,'yyyy-MM-dd HH24:mi:ss') AS NOW FROM DUAL;

select count(*) from v$process; --当前的连接数
select value from v$parameter where name = 'processes'; --数据库允许的最大连接数
select sid,serial#,username,program,machine,status from v$session WHERE PROGRAM='plsqldev.exe';
alter system kill session 'sid,serial#' ;
alter system kill session '22,13377' ; 

--建表语句
create table DM_SYS_USER
(
  id            VARCHAR2(32) not null,
  login_account VARCHAR2(100),
  login_pwd     VARCHAR2(50),
  user_code     VARCHAR2(100),
  user_name     VARCHAR2(100),
  user_alias    VARCHAR2(100),
  sex           VARCHAR2(10),
  email         VARCHAR2(100),
  user_state    VARCHAR2(10),
  user_type     VARCHAR2(100),
  memo          VARCHAR2(500),
  disp_num      NUMBER(10),
  update_user   VARCHAR2(32),
  update_date   DATE
)


comment on table DM_SYS_USER
  is '系统用户表';
-- Add comments to the columns 
comment on column DM_SYS_USER.login_account
  is '登录账号';
comment on column DM_SYS_USER.user_code
  is '用户编码,类似于学生的学号';
comment on column DM_SYS_USER.user_name
  is '用户姓名';
comment on column DM_SYS_USER.user_alias
  is '用户别名，昵称';
comment on column DM_SYS_USER.sex
  is '性别  0 男  1女';
comment on column DM_SYS_USER.user_state
  is '用户状态:R:已注册 U:已审批 L:锁定 D:删除';
comment on column DM_SYS_USER.user_type
  is '用户类型';
comment on column DM_SYS_USER.memo
  is '描述,说明';
comment on column DM_SYS_USER.disp_num
  is '排序';
comment on column DM_SYS_USER.update_user
  is '更新人';
comment on column DM_SYS_USER.update_date
  is '更新时间';
-- Create/Recreate primary, unique and foreign key constraints 
alter table DM_SYS_USER
  add constraint DM_SYS_USER primary key (ID)

--查看表占用空间大小
analyze table T_LOGSRV_SERVICE compute statistics; 

select num_rows * avg_row_len / 1024 / 1024 as "实际占用大小（M）"
  from user_tables
 where table_name = 'T_LOGSRV_SERVICE';

select sum(bytes) / (1024 * 1024) as "分配大小（M）"
  from user_segments
 where segment_name = 'T_LOGSRV_SERVICE';

--时间处理
select to_date(t.update_time,'yyyymmddhh24miss'),to_date(t.update_time,'yyyymmddhh24miss')+rownum/24/60 as cudate,rownum  from t_uaac_user t;

--添加字段
ALTER TABLE T_SMC_SERVICE_CATEGORY   ADD DELETE_FLAG  VARCHAR2(1);
ALTER TABLE T_SMC_SERVICE_CATEGORY   ADD SORT  NUMBER;

--查看当前用户下表以及表的注释信息
SELECT a.TABLE_NAME, b.COMMENTS
  FROM user_tables a, user_tab_comments b
 WHERE a.TABLE_NAME = b.TABLE_NAME
 ORDER by TABLE_NAME;

--查看数据库版本号
select * from product_component_version;