.NET Tutorials, Forums, Interview Questions And Answers
Welcome :Guest
Sign In
Win Surprise Gifts!!!

Top 5 Contributors of the Month
david stephan
Gaurav Pal

Home >> Interview Question >> Sql Server >> Post New Question Subscribe to Interview Questions

What is NOT NULL Constraint?

Posted By :Syed Shakeer Hussain     Posted Date :November 28, 2009    Points :10   Category :Sql Server 
A NOT NULL Constraint enforces that the column will not accept NULL values.The NOT NULL constraint are used to enforce domain integrity as the check constraint.

You can also find related Interview Question to What is NOT NULL Constraint?  below: 

What are NOT NULL Constraint

? A NOT NULL constraint enforces that the column will not accept null values.
? The not null constraints are used to enforce domain integrity, as the check constraints.

what is not null constraint?

It enforces thata column will not accept null value. (More...)

What is NOT NULL Constraint

A NOT NULL constraint enforces that the column will not accept null values. The not null constraints are used to enforce domain integrity, as the check constraints. (More...)

What is the difference between NULL AND VOID pointer?

NULL can be value for pointer type variables.
VOID is a type identifier which has not size.
NULL and void are not same. Example: void* ptr = NULL; (More...)

What is a Null object?

It is an object of some class whose purpose is to indicate that a real object of that class does not exist. One common use for a null object is a return value from a member function that is supposed to return an object with some specified properties but cannot find such an object. (More...)

What is Check Constraint?

Check constraint specifies a condition that is enforced for each row of the table on which the constraint is defined. Once constraint is defined, insert or update to the data within the tables is checked against the defined constraint

What is the difference between RULE and Check Constraint?

The major difference between rule and Check is reusability. 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. (More...)

Unique Key constraint

1) UNIQUE constraints are to make sure that no duplicate values are entered in specific columns that do not participate in a primary key.
2) When you are placing an unique constraint it will automatically create Unique Index to maintain the integrity.
3) Unique Allows one Null value per column where as Primary key doesn't allow null values.
4) There is no limit on having number of unqiue constraints on a table.
5) Unique Key constraint can be referenced in Foreign Key Column. (More...)

Can you control concatenation of string values with null values?

Concatenation of string values with null values results either null value or string value.
We can control that by setting CONCAT_NULL_YIELDS_NULL on or off.
When it is set to ON, the concatenation will result null and when it is set to OFF, it will result the string.
Setting it ON,
print 'testing' + NULL; --results NULL and prints nothing

Setting it OFF,

print 'testing' + NULL; -- results testing and prints the same (More...)

DateTime variables can be null (True / False )


The DateTime type is a non-nullable value type, and just like an integer, it cannot be assigned to null. (More...)

can we assign Null value to Struct variable.

No , We cannot assign null to a struct variable, since structs are value type. (More...)

Quick Links For Interview Questions Categories:
ASP.Net Windows Application   .NET Framework   C#   VB.Net   ADO.Net  
Sql Server   SharePoint   Silverlight   OOPs   JQuery   JavaScript/VBScript
Biztalk Patten/Practices .IIS WCF WPF WWF
Networking Aptitude Others   All      

Find questions, FAQ's and their answers related to .NET, C#, Vb.Net, Sql Server and many more.

Now you can find lots of .NET, C#, Vb.Net, SQL Server,Windows, ASP.Net related Questions and their Answers here at www.dotnetspark.com. Our aim is to help you pass your certification Exams (MCP, MCSD, MCAD etc.,) with flying scores and get good name in your company.

So, Start looking our Interview Question section daily and improve your .NET Skills. You can also help others by posting Interview Questions and their Answers in this section.

Hall of Fame    Twitter   Terms of Service    Privacy Policy    Contact Us    Archives   Tell A Friend