Tip

Extract CREATE scripts for foreign key constraints

This tip is useful for extracting CREATE scripts for foreign key constraints belonging to the current user. It may come handy in situations such as recreating the database at a different location, while specifying deletion rules, etc. It has been tested on both 8i and 9i. 

set serveroutput on SIZE 50000
set linesize 1000
set head off

declare
mPos Number;
mRefTab varchar2(200);

cursor cCOn is

SELECT
B.table_name table_name , a.constraint_name constraint_name
,B.POSITION POSITION, b.column_name column_name ,
a.r_constraint_name r_constraint_name
from
user_constraints a inner join user_cons_columns b
on a.constraint_name = b.constraint_name
where constraint_type='R'
order by b.constraint_name,b.position;

begin

FOR mCon in cCon Loop

IF mcon.position = 1 then
DBMS_OUTPUT.PUT_LINE( ' ALTER TABLE ' || MCON.table_name );
DBMS_OUTPUT.PUT_LINE( ' ADD CONSTRAINT ' || mcon.constraint_name || '
FOREIGN KEY (' );
END IF;

SELECT MAX(d.POSITION) into
mPos
from user_cons_columns d
WHERE d.constraint_name = mcon.constraint_name;

select table_name
into mRefTab
from user_constraints where
constraint_name=mcon.r_constraint_name;

IF mcon.position < mpos then
DBMS_OUTPUT.PUT_LINE( ' ' || mcon.column_name || ' , ');
ELSE
DBMS_OUTPUT.PUT_LINE( mcon.column_name || ' )  REFERENCES ' ) ;
DBMS_OUTPUT.PUT_LINE( mRefTab ||  ' ON DELETE CASCADE ; ' || CHR(10) ) ;
END IF;

End Loop;

End ;
/

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This was first published in August 2003

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