Child table child column count based on pareent table

Question

Hi ,
I have requirement to generate a report .
based on parent table I want find out child table and child key count.
In the below query i will give parenet table name it will give child table details and child key details
"SELECT b.table_name as table_name , d.column_name, b.R_CONSTRAINT_NAME
FROM user_constraints a, user_constraints b, user_ind_columns c, user_cons_columns d
WHERE a.constraint_type = 'P' AND
a.CONSTRAINT_NAME = b.R_CONSTRAINT_NAME AND
b.CONSTRAINT_TYPE = 'R' AND
a.table_name = c.table_name AND
a.constraint_name = c.index_name AND
b.CONSTRAINT_NAME = d.constraint_name AND
a.table_name = 'TABLENAME' "
eg ; here I will give dept table name I want emp table details
Example output
Childtable. Childkey Count
EMP 10 5
EMP 20 10
EMP 30 5
.....etc.
Please any body has solution for my requirement please help me .
Thanks
Edited by: tmadugula on Oct 26, 2012 6:25 AM
Edited by: tmadugula on Oct 26, 2012 6:28 AM
Edited by: tmadugula on 26 Oct, 2012 11:08 AM
Edited by: tmadugula on 26 Oct, 2012 11:21 AM
Edited by: tmadugula on 26 Oct, 2012 11:30 AM

Answer 1

Is what you are really asking is how many FK point to a specific table? If so, then you do not need the join to user_ind_columns or to user_cons_columns. You just join user_constraints to itself on a.r_constraint_name = b.constraint_name and b.table_name = target_table
A FK has to point to the PK or UK of the referenced table so the number of columns pointed to will equal the number of columns in the constraint so I see no need to try to count the individual column references as it will equal the number of FK to the PK or UK constraint.
HTH -- Mark D Powell --