In this post, I am sharing a T-SQL script to find a list of all CHECK Constraints of SQL Server Database.

Using CHECK Constraints, we are applying business validations or column level validations. Few DBAs also called CHECK Constraint means hidden validation or rule.

When you are working with your transaction system, you may surprise many times because of CHECK constraints.

Periodically, a DBA should prepare the report on defined CHECK Constraints which makes sure about data validation and further implementation.

SELECT 
	S.name + '.' + CC.name AS CheckContraintName 
	,O.name AS ParentObject 
	,O.type_desc AS ParentType 
	,ISNULL(C.name, N'') AS ColumnName 
	,CC.definition AS ContraintDefinition 
	,CC.is_disabled AS IsDisabled 	
FROM sys.check_constraints AS CC 
INNER JOIN sys.schemas AS S 
    ON CC.schema_id = S.schema_id 
INNER JOIN sys.objects AS O 
    ON CC.parent_object_id = O.object_id 
LEFT JOIN sys.columns AS C 
    ON CC.parent_object_id = C.object_id 
    AND CC.parent_column_id = C.column_id 
ORDER BY ParentObject        
        ,ColumnName

In this post, I am sharing a demonstration on how to validate the range of IP Address in SQL Server.

You can set CHECK CONSTRAINT for each part of IP Address for validating a proper range.

For example,
You require inserting IP Address between 10.20 range. This you can achieve using PARSENAME function of SQL Server.

Below is a full demo on this:

Let’s first create one table and define CHECK Constraint using PARSENAME.

CREATE TABLE tbl_IPAddress
(
 IPAddress VARCHAR(15)
)
GO

ALTER TABLE tbl_IPAddress ADD CONSTRAINT chk_tbl_IPAddress_IPAddress
CHECK 
(
 (ParseName(IPAddress, 4) = 12) 
 AND (ParseName(IPAddress, 3) = 4) 
 AND (ParseName(IPAddress, 2) BETWEEN 8 AND 26) 
 AND (ParseName(IPAddress, 1) BETWEEN 1 AND 255) 
)
GO

You can see different four part validation ,

First two part validation is: only IP Address range start with 12.4

Last two part validation is: 8 to 26 and 1 to 255.

Means valid IP Address are :

12.4.8.125

12.4.15.241

Invalid IP Address are:

10.2.21.52

12.4.7.124

Now insert script for some valid IP Address:

INSERT INTO tbl_IPAddress  (IPAddress) 
VALUES 
        ('12.4.8.34')
        ,('12.4.16.125')
        ,('12.4.22.120')
        ,('12.4.22.120')
        ,('12.4.15.216')
GO

If you tried to insert out of range, then this will show you an error that you cannot violate check constraint.

Script to Select different part of stored IP Address:

SELECT IPAddress
     ,ParseName(IPAddress, 4) As FirstPart
     ,ParseName(IPAddress, 3) As SecondPart
     ,ParseName(IPAddress, 2) As ThirdPart
     ,ParseName(IPAddress, 1) As FourthPart
FROM   tbl_IPAddress

My Suggestion:

In this demo, I stored IP Address into one VARCHAR(15) column which is not effective storage.
Whenever you don’t require any analysis on IP Address, then you can store the IP Address into one column. Otherwise, please visit this page on the effective storage of IP Addresses.