SQL & PL/SQL :: Insert Using Column Name To Indicate Inserted Value

I have the following tables:

CREATE TABLE test_abc(id NUMBER PRIMARY KEY, col1 NUMBER(10), col2 NUMBER(10), col3 NUMBER(10));

INSERT ALL
INTO test_abc VALUES (1,12345,34567,87654)
INTO test_abc VALUES (2,17345,37567,87754)
INTO test_abc VALUES (3,12745,34767,87674)
INTO test_abc VALUES (4,17045,30567,80754)
INTO test_abc VALUES (5,12740,34067,87604)
SELECT * FROM dual;

CREATE TABLE test_b (id NUMBER, col VARCHAR2(10), coltype_id NUMBER);

What I need to do is to convert the columns col1, clo2, col3 in test_abs into rows in test_b. but I need to do this so that the column name is what determines the value of colytype_id.So in test_b values will look like:

id col coltype
1 12345 1
1 34567 2
1 87654 3

and so on.