概述

今天主要介紹一下Oracle數據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~