oracle的序列与同义词

一.序列

1.格式：

create sequence 序列名

start with n

increment by n

maxvalue n|nomaxvalue 

minvalue n|nominvalue

cache n|nocache (把n个连续的序列号保存在内存中)

cycle n|nocycle|cycle 20 (是否循环)

2.创建一个序列

create sequence t_se

start with 2000

increment by 10

maxvalue 100000

nocache

nocycle

3.删除一个序列

 drop sequence t_se;

4.查询一个序列属性

（1）select sequence_name,min_value,max_value,increment_by,

cycle_flag,cache_size,last_number

from user_sequences

（2）

select object_name,object_type,created,status

from user_objects

where object_type!='TABLE'

and object_type!='INDEX'

5.查询序列值

select t_se.nextval from dual;（查询下一个值）

select t_se.currval from dual;（查询当前值）

6.向表中插入序列值

insert into test(id) values(t_se.nextval);

7.修改序列

alter sequence t_se

increment by 11

maxvalue 999999

cache 50

二.同义词

1.创建同义词

create   synonym zgk.t for zgk.test;

create public synonym t for zgk.test;（共有的，所有用户都可以查询）

2.删除同义词

drop synonym t;

drop public synonym t;

3.查询同义词

select * from zgk.t;

4.查询序列属性信息

select object_name,object_type from

user_objects

where object_type like 'SYN%'

5.查询序列信息

select synonym_name,table_owner,table_name

from user_synonyms