实现功能：导入excel，如果数据存在则更新，不存在测插入数据库，
问题：因数据量过多时，select count（1） from table;这个语句会执行很多次，效率太低。

在网上找到的方法使用存储过程解决：

/由于要导入多个excel，所以表名和列名都是动态的/
table_name /表名/
col_sql /列名/
condition_list /查询条件数组/
val_list in /值数组/
user_name /操作人/
today_time /操作时间/

先创建两个数组：
CREATE TYPE val_array AS TABLE OF VARCHAR2(50);
CREATE TYPE condition_array AS TABLE OF VARCHAR2(50);
如下是存储过程：
create or replace procedure insert_exists_device(table_name in VARCHAR2, col_sql in VARCHAR2, condition_list in condition_array, val_list in val_array, user_name in VARCHAR2, today_time in VARCHAR2)
is recordnum NUMBER;
BEGIN
for i in 1 .. condition_list.count loop
select count(1) into recordnum FROM table_name WHERE condition_list(i);
IF recordnum = 0 THEN
insert into table_name (id,col_sql,CREATE_PRSN,CREATE_TIME) values(sys_guid(),val_list(i),user_name,to_date(today_time,'yyyy-MM-dd hh24:mi:ss'));
ELSE
update table_name set (col_sql,MDFY_PRSON,MDFY_TIME) = (select val_list(i),user_name,to_date(today_time,'yyyy-MM-dd hh24:mi:ss') from dual) where condition_list(i);
END IF;
commit;
end loop;
END insert_exists_device;