Pushing the hierarchy levels

hI,
i have data which look like below.

Table 1 :

Code   LEAF_node         LEVEL_NUMBER DEPARTMENT

AA      2                     1                001
AA      1                     2                001

B00     2                     2               001
B11     2                     2               001
C11     2                     3               001





step 1)

This step ‘pushes down’ all levels of the hierarchy by one level,
except for level 1, thus opening up level 2 for insertionby the new Fund Focus level.
 The ‘leaf’ node at level 2, however, is left untouched: it is still at level 2.


Code   LEAF_node         LEVEL_NUMBER DEPARTMENT

AA      2                     1                001
AA      1                     2                001

B00     3                     3               001
B11     3                     3               001
C11     3                     4               001


step 2)

Insert two rows into the step 1) table using FUND_FOCUS

FUND_FOCUS
cODE  DEPARTMENT
TT      001
TT1     001

Result should be:

Code   LEAF_node         LEVEL_NUMBER DEPARTMENT

AA      2                     1                001
AA      1                     2                001
TT      2                     2                001
TT1     2                     2                001
B00     3                     3                001
B11     3                     3               001
C11     3                     4               001


There is step 3) but we can discuss that later.

Thanks