【DB笔试面试382】请编写触发器：每当在EMPLOYEES表中插入一行数据时，相应部门的职工总人数就加1。

EMPLOYEES(EID,NAME,DEPTNO)
DEPARTMENTS(DEPTNO,DEPTNAME,TOTALNUMBER)

CREATE [OR REPLACE] TRIGGER trigger_name
{BEFORE | AFTER }
{INSERT | DELETE | UPDATE [OF column [, column …]]}
ON [schema.] table_name 
[REFERENCING {OLD [AS] old | NEW [AS] new| PARENT as parent}]
[FOR EACH ROW ]
[WHEN condition]
trigger_body; 

CREATE TRIGGER INSERT_TRIGGER
  AFTER INSERT ON EMPLOYEES
BEGIN
  UPDATE DEPARTMENTS T
     SET T.TOTALNUMBER = T.TOTALNUMBER + 1
   WHERE T.DEPTNO = :NEW.DEPTNO;
END;