概述

今天主要介紹一下Oracle資料庫中多表關聯批量插入、多表關聯批量更新和多表關聯批量刪除。下面用實驗來理解下~

一、創建必須的表和序列語句

--創建部門表 dept:CREATE TABLE dept( deptno NUMBER(2) CONSTRAINT PK_DEPT PRIMARY KEY, dname VARCHAR2(14) , loc VARCHAR2(13) ,  CREATEDTIME DATE,  UPDATEDTIME DATE,  CREATEDBY NUMBER(7,0),  UPDATEDBY NUMBER(7,0)) ; --創建員工表 emp:CREATE TABLE emp(  empno NUMBER(4) CONSTRAINT PK_EMP PRIMARY KEY,  ename VARCHAR2(10),  job VARCHAR2(15),  mgr NUMBER(4),  hiredate DATE,  sal NUMBER(7,2),  comm NUMBER(7,2),  deptno NUMBER(2) CONSTRAINT FK_DEPTNO REFERENCES DEPT,   CREATEDTIME DATE,   UPDATEDTIME DATE,   CREATEDBY NUMBER(7,0),   UPDATEDBY NUMBER(7,0)); --創建員工表 emp_copy:CREATE TABLE emp_copy(  empno NUMBER(4),  ename VARCHAR2(10),  job VARCHAR2(15),  mgr NUMBER(4),  hiredate DATE,  sal NUMBER(7,2),  comm NUMBER(7,2),  deptno NUMBER(2),   CREATEDTIME DATE,   UPDATEDTIME DATE,   CREATEDBY NUMBER(7,0),   UPDATEDBY NUMBER(7,0) );--自定義一個序列  create sequence emp_sequence    increment by 1 --每次增加幾個，我這裡是每次增加1     start with 1  --從1開始計數     nomaxvalue   --不設置最大值     nocycle     --一直累加，不循環     nocache    --不建緩衝區  ;--插入dept表數據:INSERT INTO dept VALUES(10,'ACCOUNTING','NEW YORK',sysdate,sysdate,123123,123123);INSERT INTO dept VALUES (20,'RESEARCH','DALLAS',sysdate,sysdate,123123,123123);INSERT INTO dept VALUES(30,'SALES','CHICAGO',SYSDATE,SYSDATE,123123,123123);INSERT INTO dept VALUES(40,'OPERATIONS','BOSTON',sysdate,sysdate,123123,123123); --插入emp表數據:INSERT INTO emp VALUES(7369,'SMITH','CLERK',7902,to_date('17-12-1980','dd-mm-yyyy'),800,NULL,20,sysdate,sysdate,123123,123123);INSERT INTO emp VALUES(7499,'ALLEN','SALESMAN',7698,to_date('20-2-1981','dd-mm-yyyy'),1600,300,30,sysdate,sysdate,123123,123123);INSERT INTO emp VALUES(7521,'WARD','SALESMAN',7698,to_date('22-2-1981','dd-mm-yyyy'),1250,500,30,SYSDATE,SYSDATE,123123,123123);INSERT INTO emp VALUES(7566,'JONES','MANAGER',7839,to_date('2-4-1981','dd-mm-yyyy'),2975,NULL,20,sysdate,sysdate,123123,123123);INSERT INTO emp VALUES(7654,'MARTIN','SALESMAN',7698,to_date('28-9-1981','dd-mm-yyyy'),1250,1400,30,SYSDATE,SYSDATE,123123,123123);INSERT INTO emp VALUES(7698,'BLAKE','MANAGER',7839,to_date('1-5-1981','dd-mm-yyyy'),2850,NULL,30,sysdate,sysdate,123123,123123);INSERT INTO emp VALUES(7782,'CLARK','MANAGER',7839,to_date('9-6-1981','dd-mm-yyyy'),2450,NULL,10,SYSDATE,SYSDATE,123123,123123);INSERT INTO emp VALUES(7788,'SCOTT','ANALYST',7566,to_date('19-4-87','dd-mm-yyyy'),3000,NULL,20,SYSDATE,SYSDATE,123123,123123);INSERT INTO emp VALUES(7839,'KING','PRESIDENT',NULL,to_date('17-11-1981','dd-mm-yyyy'),5000,NULL,10,sysdate,sysdate,123123,123123);INSERT INTO emp VALUES(7844,'TURNER','SALESMAN',7698,to_date('8-9-1981','dd-mm-yyyy'),1500,0,30,SYSDATE,SYSDATE,123123,123123);INSERT INTO emp VALUES(7876,'ADAMS','CLERK',7788,to_date('23-5-87','dd-mm-yyyy'),1100,NULL,20,sysdate,sysdate,123123,123123);INSERT INTO emp VALUES(7900,'JAMES','CLERK',7698,to_date('3-12-1981','dd-mm-yyyy'),950,NULL,30,sysdate,sysdate,123123,123123);INSERT INTO emp VALUES(7902,'FORD','ANALYST',7566,to_date('3-12-1981','dd-mm-yyyy'),3000,NULL,20,SYSDATE,SYSDATE,123123,123123);INSERT INTO emp VALUES(7934,'MILLER','CLERK',7782,to_date('23-1-1982','dd-mm-yyyy'),1300,NULL,10,sysdate,sysdate,123123,123123);

二、多表關聯批量插入

要求:批量複製部門dept表 loc在 CHICAGO的,且工資大於1600的人員信息到emp_copy表,emp_copy的empno需要使用序列emp_sequence

INSERT INTO emp_copy SELECT emp_sequence.nextVal,C.* FROM (  SELECT   e.ename, e.JOB, e.mgr, e.hiredate, e.sal,e.comm,e.deptno,SYSDATE AS CREATEDTIME,SYSDATE AS UPDATEDTIME,  123124 AS CREATEDBY,123124 as UPDATEDBY  FROM emp e, dept d  WHERE e.deptno = d.deptno  AND d.loc='CHICAGO'  and e.sal>=1500 )C;

其中emp_sequence.nextVal保證了C.*的多條數據都能取到不同的序列值

三、多表關聯批量更新

要求:批量更新部門dept表 loc在 CHICAGO的,且職位job為'SALESMAN'的員工,comm在原來基礎上加200

MERGE INTO emp e USING  (  SELECT e1.job, e1.ename,e1.comm FROM emp e1, dept d1  WHERE e1.deptno = d1.deptno  AND d1.loc='CHICAGO'  and e1.job='SALESMAN' )t  ON (  e.job = t.job and e.ename = t.ename ) WHEN MATCHED THEN  UPDATE   set e.comm= t.comm+200;

其中e.job = t.job and e.ename = t.ename只是展示可以關聯多個條件,這裡有一個關鍵點為 USING ( … ) t 中查詢到的是一個list,而merge可以對匹配到的list進行批量更新

四、多表關聯批量刪除

要求:批量刪除部門dept表 loc在 CHICAGO的,且工資小於1500的人員信息

DELETE FROM( SELECT c.* FROM emp c,dept d WHERE d.deptno = c.deptno              AND d.loc = 'CHICAGO' and c.sal < 1500);

覺得有用的朋友多幫忙轉發哦！後面會分享更多devops和DBA方面的內容，感興趣的朋友可以關注下~