[OracleSql]DML(Data Manipulation Language) - INSERT, UPDATE

    1.INSERT
        -테이블에 자료를 삽입할 때 사용
        
        (사용형식)
        
    INSERT INTO 테이블명[컬럼명1[,컬럼명2,...])]
        VALUES(값1[,값2,...]);
        
        -'테이블명'은 자료를 삽입할 대상 테이블의 이름
        -'컬럼명1[,컬럼명2,...]': 생략하면 테이블의 모든 컬럼에 순서에 맞는 값을 배정해야함
        일부 컬럼에만 값을 지정할때에는 해당 컬럼명을 기술한다. 단, NOTNULL 항목을 생략 할 수 없다.
        
        - '값1[,값2,...]' : ' 컬럼명1[,컬럼명2,...]'에 저장될 값을 순서,타입,갯수에 맞게 기술 
        
사용예) 사원테이블에 다음 자료를 입력하시오
[자료]
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사원번호 사원명     주소                        전화번호     직위    부서명
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E001    홍길동     대전시 중구 대흥동 500번지                팀장    개발부       -- '공공서버개발부' 같이 20바이트가 넘으면 오류가남
E002    홍길순
E002    박길순     충남 천안시 성정동           123-4567            영업부 
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  INSERT INTO EMPLOYEE
        VALUES('E001','홍길동',' 대전시 중구 대흥동 500번지','','팀장','개발부'); 
        
  SELECT * FROM EMPLOYEE;
  
   INSERT INTO EMPLOYEE(EMP_ID,EMP_POSITION,EMP_NAME)
        VALUES('E002','사원','홍길순'); 
        
    INSERT INTO EMPLOYEE(EMP_ID,EMP_NAME,EMP_ADDR,TEL_NO,EMP_POSITION,DEPT_NAME)
        VALUES('E003','박길','충남 천안시','123-456',NULL,'영업부'); 
        
    UPDATE EMPLOYEE
        SET EMP_NAME = '박길순'
    WHERE EMP_ID = 'E003';
    
      SELECT * FROM EMPLOYEE;