1. 建立數(shù)據(jù)庫

備注：

1) oracle 不同于mysql 可以直接create database

2) oracle 創(chuàng)建schema時(shí)對(duì)應(yīng)一個(gè)用戶，即該schema的訪問用戶，與用戶一一對(duì)應(yīng)；但可以存在多個(gè)訪問用戶(帶權(quán)限控制)

1.1 創(chuàng)建數(shù)據(jù)庫文件

CREATE TABLESPACE XX LOGGING DATAFILE ‘D:\app\XX\oradata\orcl\XX.dbf‘ SIZE 1000M;

create temporary tablespace XX tempfile ‘D:\app\XX\oradata\orcl\XX.dbf‘ size 1000m;

1.2 創(chuàng)建用戶

CREATE USER XX IDENTIFIED BY XX DEFAULT TABLESPACE XX TEMPORARY TABLESPACE XX;

1.3 授權(quán)

grant connect, resource to XX;

grant create session to XX;

2. 數(shù)據(jù)庫操作(默認(rèn)sccot用戶)：

2.1 create

create table persons(

person_id NUMBER PRIMARY KEY,

first_name VARCHAR2(50) NOT NULL,

last_name VARCHAR2(50) NOT NULL,

score NUMBER,

type VARCHAR2(20)

);

備注：

1) ORA-02000: missing ALWAYS keyword : 在11g版本里不用用GENERATED BY DEFAULT AS IDENTITY ，要用PRIMARY KEY

2) oracle 本來只有number類型，用作number(19,2)，即有小數(shù)位；后為了兼容其他數(shù)據(jù)庫，新增int，只能是整形

2.2 insert

insert into persons values(1, ‘fred‘, ‘xu‘, 0, ‘a(chǎn)‘);

insert into persons values(SEQ_PERSON_ID.NEXTVAL, ‘fred3‘, ‘xu3‘, 0, ‘b‘)

備注：

1)oracle下設(shè)置自增沒有mysql那么簡單，步驟如下：

1.1) CREATE SEQUENCE SEQ_PERSON_ID start with 100; #創(chuàng)建一個(gè)序列

1.2) INSERT INTO persons VALUES(SEQ_PERSON_ID.NEXTVAL, ‘fred1‘, ‘xu1‘, 0, ‘a(chǎn)‘);

#此時(shí)插入persons表記錄的person_id被設(shè)置成了100

1.3)也可以采用觸發(fā)器的形式

CREATE TRIGGER persons_trigger

BEFORE INSERT ON persons

FOR EACH ROW

WHEN (new.person_id is null)

begin

select SEQ_PERSON_ID.nextval into :new.person_id from sys.dual;

end;

備注：sys.dual 是個(gè)虛擬表，oracle保證里面只有一條記錄

:new— 觸發(fā)器執(zhí)行過程中觸發(fā)表作操作的當(dāng)前行的新紀(jì)錄

:old— 觸發(fā)器執(zhí)行過程中觸發(fā)表作操作的當(dāng)前行的舊紀(jì)錄

在有觸發(fā)器之后，插入數(shù)據(jù)時(shí)不需要填寫主鍵 INSERT INTO persons(first_name, last_name, score, person_type) VALUES(‘fred2‘, ‘xu2‘, 0, ‘a(chǎn)‘);

2.3 select

select * from persons where first_name = ‘fred‘ or last_name = ‘xu1‘

select * from persons where first_name like ‘%fred%‘

select * from persons where CONCAT(first_name, last_name) like ‘%1%‘

select * from users where rownum BETWEEN 0 AND 5 #利用rownum關(guān)鍵字分頁

2.4 group by

select AVG(score), person_type from persons group by person_type

select AVG(score), person_type from persons group by person_type having person_type = ‘b‘

備注：

1)ORA-00979: not a GROUP BY expression group by?后的列要能被處理

2.5 in

select * from persons where person_type in (‘a(chǎn)‘,‘b‘);

2.6 insert all

insert all

into persons(first_name, last_name, score, person_type) values(‘test‘, ‘test‘, 1, ‘c‘)

into persons(first_name, last_name, score, person_type) values(‘test1‘, ‘test1‘, 1, ‘c1‘)

into persons(first_name, last_name, score, person_type) values(‘test2‘, ‘test2‘, 1, ‘c2‘)

SELECT 1 FROM dual;

備注：

SELECT 1 FROM dual; 最后一次select必須有

2.7 視圖

create view person_view as select * from persons where first_name like ‘%f%‘

select * from person_view;

備注：

視圖是需表，只是邏輯定義；除非是一種物化視圖，那個(gè)才是有物理占用

2.8 索引

create index person_index on persons (first_name);

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