ORACLE: Creating unique values without using sequence while multi-inserts - sql

Question

There is a parent table (MAIN_TABLE) and need to do multi-inserts into a child table(CHILD_TABLE)
for various types (TYPE_1/TYPE_2/TYPE_3 etc).
That is for single parent record I will have three childs if there are three types.
WITH MAIN_TABLE AS
(
SELECT 100 AS ID,'RICK' AS NAME,5 AS LINE FROM DUAL
UNION ALL
SELECT 101 AS ID,'TOM' AS NAME,6 AS LINE FROM DUAL
)
SELECT * FROM MAIN_TABLE;
ID NAME LINE
---------- -------------------- ----------
100 RICK 5
101 TOM 6
2 rows selected.
Need to insert parent record into the child table where for the line column it has to be populated in the increasing order.
INSERT ALL
INTO CHILD_TABLE(ID, NAME, LINE, TYPE)
VALUES (ID, NAME, LINE, 'TYPE_1')
INTO CHILD_TABLE(ID, NAME, LINE, TYPE)
VALUES (ID, NAME, LINE, 'TYPE_2')
INTO CHILD_TABLE(ID, NAME, LINE, TYPE)
VALUES (ID, NAME, LINE, 'TYPE_3')
INTO CHILD_TABLE(ID, NAME, LINE, TYPE)
VALUES (ID, NAME, LINE, 'TYPE_4')
SELECT ID, NAME, LINE
FROM MAIN_TABLE;
SQL> SELECT * FROM CHILD_TABLE
100 RICK 5 TYPE_1
101 TOM 6 TYPE_1
100 RICK 5 TYPE_2
101 TOM 6 TYPE_2
100 RICK 5 TYPE_3
101 TOM 6 TYPE_3
100 RICK 5 TYPE_4
101 TOM 6 TYPE_4
8 rows selected.
Here, instead of 5,6 as the line, I need to have 5,6,7,8,9,10,11,12.
How to go about this?
Note: 1. I cannot create sequence 2. No multiple separate inserts statements if possible.

Answer 1

I certainly hope this is a homework assignment:
INSERT INTO CHILD_TABLE
SELECT m.ID,
m.NAME,
o.MIN_LINE + ROWNUM - 1 AS LINE,
t.TYPE
FROM MAIN_TABLE m
CROSS JOIN (SELECT MIN(LINE) AS MIN_LINE FROM MAIN_TABLE) o
CROSS JOIN (SELECT 'TYPE_1' AS TYPE FROM DUAL UNION ALL
SELECT 'TYPE_2' AS TYPE FROM DUAL UNION ALL
SELECT 'TYPE_3' AS TYPE FROM DUAL UNION ALL
SELECT 'TYPE_4' AS TYPE FROM DUAL) t;
dbfiddle here

Answer 2

I would strongly recommend using an Oracle sequence whenever its possible to. If you still feel the strong need for not using a sequence then try building pseudo-sequence tables and write some PLSQL functions to perform the inserts by choosing the available sequence + 1.
Or you could do something like
creating a variable for your current max value and try to use ROW_NUMBER() OVER (ORDER BY column_name)+#your_var where #your_var= SELECT MAX(column_name) FROM child