建张表

--建表
create table interview_20190405(
       id varchar(5),
       number_of_times varchar(2)  not null, 
       company_name varchar(48) not null,
       channel varchar(32) ,
       interview_time date,
       address varchar(48),
       interview_question varchar(20),
       interview_result varchar(500)
)

--修改表名
rename interview_20190405 to interview;

--增加字段
alter table interview add create_time date;
alter table interview add update_time date;

select * from interview;

--Oracle不能直接在建表的时候写注释，而是以comment on 的形式在建好表之后加上注释
comment on table interview is ‘面试记录‘;
comment on column interview.number_of_times is ‘第几次面试‘;
comment on column interview.company_name is ‘公司名称‘;
comment on column interview.channel is ‘面试来源渠道‘;
comment on column interview.interview_time is ‘面试时间‘;
comment on column interview.address is ‘面试地址‘;
comment on column interview.interview_question is ‘面试中提到的问题‘;
comment on column interview.interview_result is ‘面试结果‘;

--看一下上面加的注释
select * from user_col_comments t where t.TABLE_NAME like ‘%INTERVIEW%‘;
select * from user_tab_comments t where t.TABLE_NAME like ‘%INTERVIEW%‘;

--增加约束，设置主键
alter table interview add constraints interview_pk primary key (id);

--新建一个sequence，用来设置主键自增长
create sequence interview_seq minvalue 1 maxvalue 999 start with 1 increment by 1;

--正式用之前得先取一下值，相当于宣告一下我要用这个序列了，给一个初始值
select  interview_seq.nextval from dual;

--修改字段
alter table interview modify (interview_question varchar(500));

--新增一条数据
insert into interview
values
  (interview_seq.currval,
   ‘1‘,
   ‘深圳市XXX科技有限公司‘,
   ‘智联‘,
   to_date(‘2019-04-02 10:00:00‘, ‘yyyy-mm-dd hh24:mi:ss‘),
   ‘深圳市XX区‘,
   ‘学了啥啊‘,
   ‘不去‘,
   sysdate,
   sysdate);
   
select * from interview t where t.id = ‘1‘;
  
update interview t  set t.update_time = sysdate where t.id = ‘1‘;