Browse DevX
Sign up for e-mail newsletters from DevX

Tip of the Day
Language: SQL
Expertise: Intermediate
Jul 12, 2005



Building the Right Environment to Support AI, Machine Learning and Deep Learning

Improve Performance by Disabling and Enabling Constraints

For most of us, working with large databases is a day-to-day activity. All too often, backup and restoration are considerably slow—usually because of the constraints imposed on the tables. Take a look at the following code:

CREATE TABLE Contractors 
 contractor_id numeric(5) not null, 
 contractor_name varchar2(50) not null, 
 CONSTRAINT contractor_pk PRIMARY KEY (contractor_id) 
In this code, PRIMARY KEY is the constraint. On creation, the constraints remain enabled. Now, assuming that it has a few million records, backing up this table is going to take a long time.

In cases like this, you can boost performance by disabling the constraint, running the backup, and then re-enabling the constraint. Here's the syntax for disabling the constraint:

ALTER TABLE table_name DISABLE constraint constraint_name
For enabling:

ALTER TABLE table_name ENABLE constraint constraint_name.
Using this code with the example, the table_name is Contractors and the constraint_name is contractor_pk.

MS Sridhar
Comment and Contribute






(Maximum characters: 1200). You have 1200 characters left.



Thanks for your registration, follow us on our social networks to keep up-to-date