How to Get the Parent - Child Relationship

Question

Hi ,
In my application having 100 tables with parent - child releation ship without using casecade constraints
i want to delete the parent with child and sub child records
Example
Table - 1
parent1
child 2
Table - 2
Child 1 - Parent 1
Parent 2
Table - 3
Child 1 - Parent 2
Parent 3
Table - 4
Child 1 - Parent 3
How to delete the parent table ? Is it any scripts available ?
Regards
Sudhakar P.

Answer 1

Hi,
1) Firstly identify the parent tables using
SELECT a.table_name, 0
FROM user_tables a, user_tab_columns b
WHERE a.table_name = b.table_name
store these in one table say ID_table
2) Identify dependent tables and sore in table say table_dependency using
SELECT LEVEL, parenttable, parentcol, childtable, childcol
FROM (SELECT UNIQUE parenttable, parentcol, childtable,
b.column_name childcol
FROM (SELECT p.table_name parenttable,
k.column_name parentcol,
k.POSITION pos,
c.table_name childtable,
c.constraint_name CONSTRAINT
FROM all_constraints p,
all_constraints c,
all_cons_columns k
WHERE p.constraint_name =
c.r_constraint_name
AND c.r_constraint_name =
k.constraint_name
AND p.constraint_type IN ('P', 'U')
AND c.constraint_type = 'R'
AND p.table_name != c.table_name
ORDER BY p.table_name,
c.constraint_name,
k.POSITION) a,
all_cons_columns b
WHERE a.CONSTRAINT = b.constraint_name
AND a.pos = b.POSITION)     
3)Now using these details find tables without cascade rule as below
SELECT *
FROM table_dependency
WHERE child_table IN (
SELECT DISTINCT table_name
FROM user_constraints
WHERE constraint_type = 'R'
AND delete_rule <> 'CASCADE'
AND table_name IN (SELECT child_table
FROM table_dependency)
AND r_constraint_name IN (
SELECT constraint_name
FROM user_constraints
WHERE table_name IN (
SELECT table_name
FROM id_table
UNION
SELECT child_table
FROM table_dependency))
AND table_name NOT IN (
SELECT table_name
FROM id_table));