Oracle数据库学习-Day2

1.创建表

CREATE TABLE TBL_BOOK(

ID INT NOT NULL,

TITLE VARCHAR2(100) NOT NULL,

AUTHER VARCHAR2(20),

PRICE NUMBER

);

2.插入项

INSERT INTO TBL_BOOK VALUES(1,’thurder,‘java’,200

);

INSERT INTO TBL_BOOK VALUES(1,’kitble’,‘bbbb’,100

);

commit;

3.修改项

UPDATE TBL_BOOK SET ID=2 WHERE TITLE=’SQL’;

commit;

4.查表

SELECT * FROM TBL_BOOK;

6增加列数

alter tableTBL_BOOK add pagenum int;

7删除列

alter table drop column pagenum;

8.增加主键值

alter table TBL_BOOK add constraintpk_tbl_book_id primary key (id);

9唯一索引

create unique index uni_isbn onbooks(isbn);

10，引用外键

userid int not null,

foreign key (userid) REFERENCES tbl_user(id),

一条语句插入多行数句

insertinto t1 (col1,col2,col3,…)

select ’’,’’,’’ from dualunion

select ’’,’’,’’ from dualunion

select ’’,’’,’’from dual

创建序列

-- Create sequence

create sequence STUDENT_SEQ

min value 0

max value 9999999999

start with 0

increment by 1

cache 2

cycle;

 

 

创建触发器，自动生成主键列值

create or replace trigger tablename_t before inserton tablename

for each row

begin

if inserting then

select table name_seq.nextval into :new.id fromdual;

end if;

end;