我有两个表，一个叫做emp\u info的父表和一个叫做emp\u attention的子表，它们由empid连接。
目前，我使用两个不同的序列，每个表一个序列来创建empid。对于empèu考勤表，我创建了一个具有空值的记录，然后使用随机日期时间字段插入或更新。ses代码如下。
我想去掉emp\u attention seq序列和合并代码，执行嵌套插入或使用emp\u info表中的empid来填充emp\u attention表。
你能为我的要求提供解决办法吗。
投放序列emp\ U info\ seq；删除表emp\u info；投放顺序emp\ U seq；员工考勤表；

Create sequence  emp_info_seq;

CREATE TABLE emp_info(
   empid INTEGER,
 empname VARCHAR2(50)
);

INSERT INTO  emp_info 
SELECT emp_info_seq.NEXTVAL,
DBMS_RANDOM.string('U', 
  DBMS_RANDOM.value(3,15))
FROM    dual
CONNECT BY  LEVEL  <=3;

Create sequence
emp_attendance_seq;

CREATE TABLE  emp_attendance    
(empid INTEGER,
 start_date DATE,
 end_date DATE );

INSERT INTO  emp_attendance
(empid)
SELECT
emp_attendance_seq.NEXTVAL
FROM    dual
CONNECT BY  LEVEL  <= 3   ;

MERGE INTO  emp_attendance  dst
USING  (
           WITH    cntr (n)  AS
           (
               SELECT  LEVEL  AS n
               FROM    dual
               CONNECT BY  LEVEL <=5

       )
       ,    got_start_date (rid, empid, start_date)   AS
       (
           SELECT  CASE
                       WHEN  cntr.n  = 1
                       THEN  e.ROWID
                   END
    ,       e.empid
           ,       trunc(sysdate)
                       + dbms_random.value (1, 30)
           FROM    emp_attendance  e
           CROSS JOIN              cntr
           WHERE   e.start_date  IS NULL
       )
       SELECT  rid
       ,       empid
       ,       start_date
       ,       start_date + dbms_random.value (0, .75)  AS end_date
       FROM    got_start_date
   )  src
ON  (dst.ROWID  = src.rid)
WHEN MATCHED THEN UPDATE
    SET  dst.start_date = src.start_date
    ,    dst.end_date   = src.end_date
WHEN NOT MATCHED THEN.   
INSERT (dst.empid, dst.start_date, dst.end_date)
       VALUES (src.empid,  src.start_date, src.end_date)
;

/

EMPID    START_DATE     END_DATE
1    20200603 20:06:47    20200603 21:51:02
1    20200611 08:07:12    20200611 20:34:13
1    20200614 10:24:01    20200614 17:16:12
2    20200616 04:50:04    20200616 19:08:22
2    20200608 19:39:52    20200608 21:01:01
2    20200613 00:56:53    20200613 08:23:10
3    20200615 13:46:58    20200616 01:30:50
3    20200621 03:15:32    20200621 07:54:38
3    20200613 04:13:58    20200613 06:38:28