首先要明白一點,為什么會有批量這一個概念,無非就是數(shù)據(jù)太多了,在java端把數(shù)據(jù)查出來然后在按照100-300的批次進行更新太耗性能了,而且寫出來的代碼會非常的臃腫,所謂好的實現(xiàn)是用最少的,最精簡的代碼實現(xiàn)需求,代碼越少,留給自己犯錯誤的機會更少。
還有一個知識點就是多表關(guān)聯(lián),對于查詢肯定是可以多表關(guān)聯(lián)的,其實對于除了查詢之外也是可以進行多表關(guān)聯(lián)過濾數(shù)據(jù)的,從而達到在Oracle中查到目標數(shù)據(jù)即可更新,從而規(guī)避規(guī)避以往需要單獨查一次數(shù)據(jù)然后在按照100-300的批次做插入,更新,刪除的操作 。
--創(chuàng)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(chuàng)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(chuàng)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,我這里是每次增加1
start with 1 --從1開始計數(shù)
nomaxvalue --不設(shè)置最大值
nocycle --一直累加,不循環(huán)
nocache --不建緩沖區(qū)
--插入dept表數(shù)據(jù):
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(shù)據(jù):
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);
要求:批量復(fù)制部門dept表 loc在 CHICAGO的,且工資大于1600的人員信息到emp_copy表,emp_copy的empno需要使用序列emp_sequence
其中e.job = t.job and e.ename = t.ename只是展示可以關(guān)聯(lián)多個條件,這里有一個關(guān)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
以上所述是小編給大家介紹的Oracle中多表關(guān)聯(lián)批量插入批量更新與批量刪除操作,希望對大家有所幫助,如果大家有任何疑問請給我留言,小編會及時回復(fù)大家的。在此也非常感謝大家對腳本之家網(wǎng)站的支持!
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