Manage Learn to apply best practices and optimize your operations.

Enable the referential integrity constraint

Enable the foreign key constraints when you enable the primary key constraints.

In Oracle, there is an option to disable a primary key constraint with the cascade option in the ALTER TABLE command. This option disables the primary key constraint as well as the foreign key constraints of all the tables that reference this table. But when you enable the primary key constraint then the foreign key constraints of all those tables will not be enabled because there is no option like we have in the disable (ie, the cascade option). I think that the following query will do the trick:

select 'Alter table ' || table_name || ' enable constraint ' || constraint_name || ';' 
from user_constraints where constraint_type='R' and r_constraint_name=(select constraint_name 
from user_constraints where constraint_type='P' and table_name='the parent table name goes here');

Reader Feedback

Kim R. writes: If you disable a unique or primary key constraint that is using a unique index, Oracle drops the unique index. That can be a gotcha if one isn't aware of it.

For More Information

  • Feedback: E-mail the editor with your thoughts about this tip.
  • More tips: Hundreds of free Oracle tips and scripts.
  • Tip contest: Have an Oracle tip to offer your fellow DBAs and developers? The best tips submitted will receive a cool prize -- submit your tip today!
  • Ask the Experts: Our SQL, database design, Oracle, SQL Server, DB2, metadata, and data warehousing gurus are waiting to answer your toughest questions.
  • Forums: Ask your technical Oracle questions--or help out your peers by answering them--in our active forums.
  • Best Web Links: Oracle tips, tutorials, and scripts from around the Web.

Dig Deeper on Oracle and SQL

Start the conversation

Send me notifications when other members comment.

Please create a username to comment.