我建议你不要把这些东西存放起来 SEQ 价值观。你为什么要这么做？无论何时需要都很容易计算。怎样？像这样，使用 row_number 分析函数：

SQL> with b (id, name) as
  2    (select 1, 'TRI'   from dual union all
  3     select 1, 'TRI'   from dual union all
  4     select 1, 'TRI'   from dual union all
  5     select 2, 'ROHIT' from dual union all
  6     select 2, 'ROHIT' from dual union all
  7     select 3, 'RAVI'  from dual
  8    )
  9  select id,
 10    name,
 11    row_number() over (partition by id order by null) seq
 12  from b;
        ID NAME         SEQ
---------- ----- ----------
         1 TRI            1
         1 TRI            2
         1 TRI            3
         2 ROHIT          1
         2 ROHIT          2
         3 RAVI           1
6 rows selected.
SQL>

如果你还想储存它，现在你知道怎么储存了。

没有多个序列。只需在b表中使用一个序列，并接受每个序列都有间隙 ID 如果需要顺序值，可以根据需要使用 ROW_NUMBER() 分析函数，如果需要的话，把它放到一个视图中。另外，不要从表中复制名称 A 在表中 B ; 保持数据正常化。

CREATE TABLE A (
  id   NUMBER(8,0)
       GENERATED ALWAYS AS IDENTITY
       CONSTRAINT A__id__pk PRIMARY KEY,
  name VARCHAR2(20)
);
CREATE TABLE B (
  id   NUMBER(8,0)
       CONSTRAINT B__id__nn NOT NULL
       CONSTRAINT B__id__fk REFERENCES A(id),
  seq  NUMBER(8,0)
       GENERATED ALWAYS AS IDENTITY
       CONSTRAINT B__seq__pk PRIMARY KEY
);

然后可以创建示例数据：

INSERT INTO A ( name )
SELECT 'TRI' FROM DUAL UNION ALL
SELECT 'ROHIT' FROM DUAL UNION ALL
SELECT 'RAVI' FROM DUAL;
INSERT INTO B ( id )
SELECT 1 FROM DUAL UNION ALL
SELECT 1 FROM DUAL UNION ALL
SELECT 2 FROM DUAL UNION ALL
SELECT 3 FROM DUAL UNION ALL
SELECT 2 FROM DUAL UNION ALL
SELECT 1 FROM DUAL;

以及：

SELECT *
FROM   B

输出：

ID | SEQ
-: | --:
 1 |   1
 1 |   2
 2 |   3
 3 |   4
 2 |   5
 1 |   6

如果需要输出，请创建一个视图：

CREATE VIEW B_view ( id, name, seq ) AS
SELECT b.id,
       a.name,
       ROW_NUMBER() OVER ( PARTITION BY b.id ORDER BY seq )
FROM   B
       INNER JOIN A
       ON ( B.id = A.id )

然后：

SELECT *
FROM   b_view

输出：

ID | NAME  | SEQ
-: | :---- | --:
 1 | TRI   |   1
 1 | TRI   |   2
 1 | TRI   |   3
 2 | ROHIT |   1
 2 | ROHIT |   2
 3 | RAVI  |   1

db<>在这里摆弄