如何拆分设置值并在触发器PL / SQL中插入每一行？

Question

i have one order table. i need before inserting order table, create and using triggers insert given below format.
example:
question:

id value
1 2,5,8

answer:

id value
1 2
1 5
1 8

Answer 1

Triggers in Oracle have mode "INSTEAD OF" which is exactly what you need, but the problem is that you can't use "INSTEAD OF" trigger on a simple table, it's only available for views. So the only option I see for you is to wrap your table in a view. For example you have a table:

create table my_table(c_id number, c_value varchar2(5))

Rename it and create view with old table' name:

rename my_table to my_table_old;

create view my_table as select * from my_table_old;

All existing queries to my_table should work with this view, including updates and deletes. Now we can create INSTEAD OF trigger:

create or replace trigger t_my_table
instead of insert on my_table
for each row
declare
  qid number;
begin
  insert into my_table_old
  select :new.c_id, regexp_substr (:new.c_value, '[^,]+', 1, level) as part
  from dual  
  connect by level <= length (regexp_replace (:new.c_value, '[^,]+'))  + 1;
end;

This hierarchial query will turn comma-separated string into a table with single value in a row.

OK, let's check if it works:

SQL> insert into my_table values (1, '2,5,8');

1 row created.

SQL> select * from my_table;

      C_ID C_VALUE
---------- ---------------
         1 2
         1 5
         1 8

Simple single-value insert will also work:

SQL> insert into my_table values (2, '100');

1 row created.

SQL> select * from my_table;

      C_ID C_VALUE
---------- ---------------
         1 2
         1 5
         1 8
         2 100

Note that using of trigger will affect performance of insert queries for a bit.

Answer 2

You can amend the regex to suit your exact requirements but the following performs effectively as per your question:

CREATE OR REPLACE TRIGGER XX_ORDER_TRG 
BEFORE INSERT ON XX_ORDER_TBL
FOR EACH ROW
DECLARE 

l_num1 NUMBER;
l_num2 NUMBER;
l_num3 NUMBER;

BEGIN

/* If the whole string in value matches 3 single digits separated by commas */
IF  REGEXP_LIKE(:new.value,'^(\d{1},\d{1},\d{1})$') THEN
    /* Split the value into its 3 separate digits - Capture Groups are not supported natively*/
    l_num1 := REGEXP_SUBSTR(:new.value,'\d{1}',1,1);
    l_num2 := REGEXP_SUBSTR(:new.value,'\d{1}',1,2);
    l_num3 := REGEXP_SUBSTR(:new.value,'\d{1}',1,3);

    :new.value := l_num1;
    INSERT INTO XX_TBL (id, value) VALUES (:new.id, l_num2);
    INSERT INTO XX_TBL (id, value) VALUES (:new.id, l_num3);

END IF;           


END;