目錄一、簡單建表二、查看表結(jié)構(gòu)(在Xshell中輸入才能夠執(zhí)行)三、設(shè)置自增序列(一)普通自增序列(二)復雜序列四、修改表中的數(shù)據(jù)總結(jié)一、簡單建表CREATE TABLE teacher1( id number, name varchar2(32), primary key (id)); select * from teacher1; -- 插入數(shù)據(jù)insert into teacher1(id, name) VALUES (7, 'zhangsan'); -- 插入數(shù)據(jù)后確認無誤一定要提交，否則不會保存commit ; -- 修改表名alter table teacher rename to teacher1; -- 刪除表drop table teacher1; -- 提交事務(wù)commit;二、查看表結(jié)構(gòu)(在Xshell中輸入才能夠執(zhí)行)

desc 表名

三、設(shè)置自增序列

序列是 Oracle 提供的用于產(chǎn)生一系列 唯一數(shù)字 的數(shù)據(jù)庫對象。

(一)普通自增序列

1.創(chuàng)建序列，oracle中沒有自增，創(chuàng)建序列相當于等差數(shù)列自增

通過序列的偽列訪問序列值說明NEXTVAL返回序列的下一個值CURRVAL返回序列的當前值

注意：在剛建立序列后，無法提取當前值，只有先提取下一個值時才能再次提取當前值。ORA-08002: sequence SEQ_TEST.CURRVAL is not yet defined in this session

創(chuàng)建默認序列規(guī)則是從1開始，每次+1

-- 創(chuàng)建序列名稱create sequence teacher_seq; -- 提取下一個值select teacher_seq.nextval from DUAL; -- 提取當前值select teacher_seq.currval from DUAL;

2.刪除序列

drop sequence 序列名;

3.建表的同時設(shè)置主鍵自增的步驟

-- 先創(chuàng)建表create table teacher( id number, name varchar2(32), pwd varchar2(32), primary key (id)); -- 再創(chuàng)建序列create sequence teacher_seq; -- 插入三條數(shù)據(jù)，將主鍵id設(shè)置為序列的下一個值，這個就相當于自增insert into teacher values (teacher_seq.nextval,'zs','123');insert into teacher values (teacher_seq.nextval, 'lx', '456');insert into teacher(id, name, pwd) values (teacher_seq.nextval, 'ww', '123'); -- 插入數(shù)據(jù)后確認無誤一定要提交，否則不會保存commit ; select * from teacher;

(二)復雜序列

1.復雜序列模板

-- 創(chuàng)建序列名稱CREATE SEQUENCE 'sequence_name'-- 遞增`n`的序列（默認：`1`）-- 如果`n`是正數(shù)就遞增-- 如果`n`是負數(shù)就遞減[INCREMENT BY 'n']-- 開始值（遞增默認是`minvalue`，遞減默認是`maxvalue`）[START WITH 'n'] -- 最大值[{MAXVALUE 'n' | NOMAXVALUE}]-- 最小值[{MINVALUE 'n' | NOMINVALUE}]-- 循環(huán) | 不循環(huán)（默認：`NOCYCLE`）[{CYCLE | 'NOCYCLE'}] -- 分配并存入到內(nèi)存中（默認：`CACHE`）[{'CACHE' 'n' | NOCACHE}];

2.復雜序列案例

-- 創(chuàng)建序列規(guī)則是：從100開始，每次+1create sequence teacher_seq2 start with 100;select teacher_seq2.nextval from DUAL; -- 創(chuàng)建序列規(guī)則是：從5開始到100，超出最大值后無法創(chuàng)建create sequence teacher_seq3 minvalue 5 maxvalue 100;select teacher_seq3.nextval from DUAL; -- 創(chuàng)建序列規(guī)則是：從1開始，步長為3的方式遞增create sequence teacher_seq4 increment by 3;select teacher_seq4.nextval from DUAL; -- 創(chuàng)建復雜序列create sequence teacher_seq5 increment by 4 start with -2 minvalue -2 maxvalue 10;select teacher_seq5.nextval from DUAL; -- 刪除其中一個序列drop sequence teacher_seq5;四、修改表中的數(shù)據(jù)update teacher set pwd='123456' where id = 2;update teacher set pwd='654321',name='lss' where id = 3;總結(jié)

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