Month: June 2011

Find Foreign Key Relationships

The below query lists all of the foreign keys and the parent table and columns to which they relate.

SELECT a.owner , a.table_name , c.column_name ,
 b.owner , b.table_name , d.column_name 
FROM dba_constraints a, dba_constraints b,
 dba_cons_columns c, dba_cons_columns d
WHERE a.r_constraint_name = b.constraint_name
 AND a.constraint_type = 'R'
 AND b.constraint_type = 'P'
 AND a.r_owner=b.owner
 AND a.constraint_name = c.constraint_name
 AND b.constraint_name=d.constraint_name
 AND a.owner = c.owner
 AND a.table_name=c.table_name
 AND b.owner = d.owner
 AND b.table_name=d.table_name;

Source

 

 

DB_BLOCK_SIZE

This parameter in the init.ora is the most important. This can be done only during creation time. If you have already created the Database you cannot change this value. You will have to re-create the Database with a different size.

show parameter DB_BLOCK_SIZE;
SELECT
 name, value, display_value, description
 FROM
 v$parameter
 WHERE
 name = lower('DB_BLOCK_SIZE');