Difference between Constraints and Rules in SQL

Question

0.00/5 (No votes)

See more:

What is the difference between using constraints and rules in SQL, preferably SQL server 2008 R2. Can anyone explain and demonstrate with a real time example

Posted 20-Jun-13 18:45pm

Divakar Raj M

Add a Solution

4 solutions

Solution 4

Rules are a backward-compatibility feature that performs some of the same functions as CHECK constraints.
CHECK constraints are the preferred, standard way to restrict the values in a column.
CHECK constraints are also more concise than rules; there can only be one rule applied to a column, but multiple CHECK constraints can be applied. CHECK constraints are specified as part of the CREATE TABLE statement, while rules are created as separate objects and then bound to the column.

Important about RULE:
This feature will be removed in a future version of Microsoft SQL Server. Avoid using this feature in new development work, and plan to modify applications that currently use this feature.
Refer: http://technet.microsoft.com/en-us/library/ms188064(v=sql.105).aspx[^]

Posted 20-Jun-13 21:25pm

Prasad_Kulkarni

Comments

Rajesh Anuhya 21-Jun-13 3:27am

Have my +5 for formatting and Good answer
--RA

Solution 2

Check here,

Contraints_vs_rules.

Posted 20-Jun-13 20:40pm

Alexander andri

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Anh Nguyen Trong · Accepted Answer · 2013-06-20T20:39:00

RULE

1. The first one:
I think that Rule is one of constrains.
2. Rule can assign more than one fields in table, objects

CONSTRAINTS

Constraints allow you to define the way Microsoft® SQL Server™ automatically enforces the integrity of a database. Constraints define rules regarding the values allowed in columns and are the standard mechanism for enforcing integrity.

See link to get more details

http://msdn.microsoft.com/en-us/library/aa174546%28v=sql.80%29.aspx[^]

Hope that is useful.

Trong Anh

Mukesh Ghosh · Accepted Answer · 2013-06-20T21:08:00

The major difference between rule and Check is re usability. Check constraint is associated with columns in a Table. So these can't be re-used. Rules are defined with in a database and can be applied to any number of columns.

Eg.

CREATE TABLE Persons
(
P_Id int NOT NULL CHECK (P_Id>0),
LastName varchar(255) NOT NULL,
FirstName varchar(255),
Address varchar(255),
City varchar(255)
)

Difference between Constraints and Rules in SQL

4 solutions

Solution 4

Solution 1

Solution 2

Solution 3

Add your solution here

Preview 0