Why would you like to
change the company?
1) I am looking for a more
challenging career in a firm with a larger employee base such as yours.
2) Keeping in mind my career
goals, the time has come for me to move onto the next rung of the ladder and
make a mark for myself. This can be achieved in a company like this.
3) It is just a career move to
enhance my knowledge in my own area of interest. After completion of this
question only interview will go for further questions
Difference between
stored procedure and function
1) Procedure can return zero or n
values whereas function can return one value which is mandatory.
2) Procedures can have input,
output parameters for it whereas functions can have only input parameters.
3) Procedure allows select as
well as DML statement in it whereas function allows only select statement in
it.
4) Functions can be called from
procedure whereas procedures cannot be called from function.
5) Exception can be handled by
try-catch block in a procedure whereas try-catch block cannot be used in a
function.
6) We can go for transaction
management in procedure whereas we can't go in function.
7) Procedures cannot be utilized
in a select statement whereas function can be embedded in a select statement.
Difference between
Abstract and Interface
Abstract Class:
-Abstract class provides a set of rules to implement next
class
-Rules will be provided through abstract methods
-Abstract method does not contain any definition
-While inheriting abstract class all abstract methods must
be override
-If a class contains at least one abstract method then it
must be declared as an “Abstract Class”
-Abstract classes cannot be instantiated, but a reference
cannot be created
-Reference depends on child class object’s memory
-Abstract classes are also called as “Partial abstract
classes”
-Partial abstract class may contain functions with body and
functions without body
-If a class contains all functions without body then it is
called as “Fully Abstract Class” (Interface)
Interface:
-If a class contains all abstract methods then that class is
known as “Interface”
-Interfaces support like multiple inheritance
-In interface all methods r public abstract by default
-Interfaces r implementable
-Interfaces cannot be instantiated, but a reference can be
created
Index types in SQL
Server
Clustered Index
Only 1 allowed per table physically rearranges the data in
the table to confirm to the index constraints for use on columns that are
frequently searched for ranges of data for use on columns with low selectivity.
Non-Clustered Index
Up to 249 allowed per table creates a separate list of key
values with pointers to the location of the data in the data pages For use on
columns that are searched for single values
A clustered index is a special type of index that reorders
the way records in the table are physically stored. Therefore table can have
only one clustered index. The leaf nodes of a clustered index contain the data
pages. A non-clustered index is a special type of index in which the logical
order of the index does not match the physical stored order of the rows on
disk. The leaf node of a non-clustered index does not consist of the data
pages. Instead, the leaf nodes contain index rows.
Included Column Index
(New in SQL Server 2005)
In SQL Server 2005, the functionality of non-clustered
indexes is extended by adding non-key columns to the leaf level of the
non-clustered index. Non-key columns can help to create cover indexes. By
including non-key columns, you can create non-clustered indexes that cover more
queries. The Database Engine does not consider non-key columns when calculating
the number of index key columns or index key size. Non-key columns can be
included in non-clustered index to avoid exceeding the current index size
limitations of a maximum of 16 key columns and a maximum index key size of 900
bytes. Another advantage is that using non-key column in index we can have
index data types not allowed as index key columns generally.
In following example column Filename is varchar(400), which
will increase the size of the index key bigger than it is allowed. If we still
want to include in our cover index to gain performance we can do it by using
the Keyword INCLUDE.
USE AdventureWorks
GO
CREATE INDEX IX_Document_Title
ON Production.Document (Title, Revision)
INCLUDE (FileName)
Non-key columns can be included only in non-clustered
indexes. Columns can’t be defined in both the key column and they INCLUDE list.
Column names can’t be repeated in the INCLUDE list. Non-key columns can be
dropped from a table only after the non-key index is dropped first. For
Included Column Index to exist there must be at least one key column defined
with a maximum of 16 key columns and 1023 included columns.
Avoid adding unnecessary columns. Adding too many index
columns, key or non-key as they will affect negatively on performance. Fewer
index rows will fit on a page. This could create I/O increases and reduced
cache efficiency. More disk space will be required to store the index. Index
maintenance may increase the time that it takes to perform modifications,
inserts, updates, or deletes, to the underlying table or indexed view.
Another example to test:
Create following Index on Database AdventureWorks in SQL
SERVER 2005
USE AdventureWorks
GO
CREATE NONCLUSTERED INDEX IX_Address_PostalCode
ON Person.Address (PostalCode)
INCLUDE (AddressLine1, AddressLine2, City, StateProvinceID)
GO
Test the performance of following query before and after
creating Index. The performance improvement is significant.
SELECT AddressLine1, AddressLine2, City, StateProvinceID,
PostalCode
FROM Person.Address
WHERE PostalCode BETWEEN '98000'
AND '99999';
GO
Interview questions
What are differences
between Array list and Hash table?
Ans: 1) Hash table store data as
name, value pair. While in array only value is store.
2) To access value from hash
table, you need to pass name. While in array, to access value, you need to pass
index number.
3) you can store different type
of data in hash table, say int, string etc. while in array you can store only
similar type of data.
What are differences
between system.stringbuilder and system.string?
The main difference is system.string is immutable and
system.stringbuilder is a mutable. Append keyword is used in string builder but
not in system.string.
Immutable means once we created we cannot modified. Suppose
if we want give new value to old value simply it will discarded the old value
and it will create new instance in memory to hold the new value.
What are the
differences between Application object and session object?
Ans: The session object is used to maintain the session of
each user. If one user enter in to the application then they get session id if
he leaves from the application then the session id is deleted. If they again
enter in to the application they get different session id.
But for application object the id is maintained for whole
application.
What are the
different types of indexes?
Ans: Two types of indexes are there one is clustered index
and non-clustered index
How many types of
memories are there in .net?
Ans: Two types of memories are there in .net stack memory
and heap memory
Is it possible to set
the session out time manually?
Ans: Yes we can set the session out time manually in
web.config.
What are differences
between function and stored procedure?
Ans:
1) Function returns only one value but procedure returns one
or more than one value.
2) Function can be utilized in select statements but that is
not possible in procedure.
3) Procedure can have an input and output parameters but
function has only input parameters only.
4) Exceptions can be handled by try catch block in
procedures but that is not possible in function.
What are the
differences between Abstract and interface?
Ans:
1) Abstract and interfaces cannot be instantiated but we can
inherit.
2) Interface contain only declarations no definitions.
Abstract contain declarations and definitions.
3) The class which contains only abstract methods is
interface class. A class which contains abstract method is called abstract
class
4) Public is default access specifier for interface we don’t
have a chance to declare other specifiers. In abstract we have chance to
declare with any access specifier
Can you Explain Page
lifecycle in .net?
Can you Explain .NET
architecture in .net?
What is the
difference between primary key and unique key with not null?
Ans: There is no difference between primary key and unique
key with not null.
What is boxing and
unboxing concepts in .net?
Ans: Boxing is a process of converting value type into
reference type
Unboxing is a process of converting reference type to value
type.
What are the
differences between value type and reference type?
Ans: Value type contain variable and reference type are not
containing value directly in its memory.
Memory is allocated in managed heap in reference type and in
value type memory allocated in stack. Reference type ex-class value
type-struct, enumeration
Is it possible to
host the website from desktop?
Ans: Yes
Why we go for page
rendering in Asp.Net Page life cycle?
Ans: Browser understands an only html control that’s why in
page rendering we will convert the aspx controls into html controls.
Write a sample query
for self join?
Ans: Select e1.ename, e2.empid from emp e1, emp e2 where
e1.empid=e2.mgrid;
Can we change the
index of primary key on table?
Ans: No
How to change the
name of the table or stored procedure in sql?
Ans: sp_rename oldtablename newtablename
For changing the column name
Sp_rename
‘tablename.[Oldcolumnname]’,’newcolumnname’,’Column’
Ex:sp_rename ‘tblemp.first’,’namechange’,’Column’
How to find out which
index is defined on table?
Ans: sp_helpindex tablename
Can you write the
program to find the length of string without using library function?
Ans: for (int i=0; str[i]!=”\n”; i++)
{
Count++;
}
What is the
difference between scope_identity() and current_identity()?
Ans: Scope_identity and current _identity both are similar
and it will return the last identity value generated in the table.
Scope_Identity will return the identity value in table that
is currently in scope
What are difference
between GET and POST Methods?
Ans:
GET Method ():
1) Data is appended to the URL.
2) Data is not secret.
3) It is a single call system
4) Maximum data that can be sent is 256.
5) Data transmission is faster
6) this is the default method for many browsers
POST Method ():
1) Data is not appended to the URL.
2) Data is Secret
3) it is a two call system.
4) There is no Limit on the amount of data. That is
characters any amount of data can be sent.
5) Data transmission is comparatively slow.
6) No default and should be explicitly specified.
What are difference
between truncate and delete?
Ans: 1) Delete keep the lock over each row where Truncate
keeps the lock on table not on all the row.
2) Counter of the Identity column is reset in Truncate where
it is not reset in Delete.
3) Trigger is not fired in Truncate where as trigger is
fired in Delete.
4) In TRUNCATE we cannot rollback.
5) In DELETE we can rollback
What is the
difference Grid View and between Data Grid (Windows)?
Ans:
1) GridView Control Enables you to add sorting, paging and
editing capabilities without writing any code.
2)GridView Control Automatically Supports paging by setting
the ‘PagerSetting’ Property.The Page Setting Property supports four Modles
a. Numeric(by default)
b. Next Previous
c. NumericFirstLast
d. Next PreviousLast
3)It is Used in asp.net
4)GridView Supports RowUpdating and RowUpdated Events.
5)GidView is Capable of Pre-Operations and Post-Operations.
6)GridView Has EditTemplates for this control
7)It has AutoFormat
DataGrid(Windows)
1)DataGid Control raises single Event for operations
2)DataGird Supports the SortCommand Events that occur when a
column is Soted.
3)DataGrid Supports UpdataCommand Event that occurs when the
UpdateButton is clicked for an item in the grid.
4)DataGrid is used in Windows GUI Application.
5)It doesnot have EditTemplates for this control
6)It doesnot have AutoFormat
If I write
System.exit (0); at the end of the try block, will the finally block still
execute?
Ans: No in this case the finally block will not execute
because when you say system.exit(0),the control immediately goes out of the
program, and thus finally never executes.
What are the
different levels of State management in ASP.NET?
Ans:
State management is the process by which you maintain state
and page information over multiple requests for the same or different pages.
There are 2 types State Management:
1. Client – Side State Management
This stores information on the client's computer by
embedding the information into a Web page, a uniform resource locator (url), or
a cookie. The techniques available to store the state information at the client
end are listed down below:
a. View State – Asp.Net uses View State to track the values
in the Controls. You can add custom values to the view state. It is used by the
Asp.net page framework to automatically save the values of the page and of each
control just prior to rendering to the page. When the page is posted, one of
the first tasks performed by page processing is to restore view state.
b. Control State – If you create a custom control that
requires view state to work properly, you should use control state to ensure
other developers don’t break your control by disabling view state.
c. Hidden fields – Like view state, hidden fields store data
in an HTML form without displaying it in the user's browser. The data is
available only when the form is processed.
d. Cookies – Cookies store a value in the user's browser
that the browser sends with every page request to the same server. Cookies are
the best way to store state data that must be available for multiple Web pages
on a web site.
e. Query Strings - Query strings store values in the URL
that are visible to the user. Use query strings when you want a user to be able
to e-mail or instant message state data with a URL.
2. Server – Side State Management
a. Application State - Application State information is
available to all pages, regardless of which user requests a page.
b. Session State – Session State information is available to
all pages opened by a user during a single visit.
Both application state and session state information is lost
when the application restarts. To persist user data between application
restarts, you can store it using profile properties.
Abstract Class:
Abstract class is a class which cannot be instantiated.
Class should have “Abstract” key word with the name. In any one of the method of class having
abstract method with in it, then it should be define as abstract class. The
class which derived the abstract class should have definition of the abstract
method. These classes which derived the abstract class and implement the
abstract methods call concrete class.
Abstract class may have the definition of function or may
not. Below is the simple example of an
abstract class
public abstract class AbstractStudent
{
String Roll
{
get;
set;
}
String
FirstName
{
get;
set;
}
String
LastName
{
get;
set;
}
Public String
GetStudentDetails()
{
//
Implementation of Method
}
public String
SaveStudentDetails ()
{
// Implementation of Method
}
public
abstract String CalculateWage();
}
So, the class having one abstract method so we need to
mention the class as "abstract" .
Difference between
Abstract Class and Interface?
Abstract class is a class which cannot be instantiated and
which can have methods with definition as well as declaration also. This can be
inherited.
As for Example:
public abstract class AbstractStudent
{
String Roll
{
get;
set;
}
String
FirstName
{
get;
set;
}
String
LastName
{
get;
set;
}
Public String
GetStudentDetails()
{
// Implementation of Method
}
public String
SaveStudentDetails ()
{
//
Implementation of Method
}
public
abstract String CalculateWage();
}
Interface can only contain the methods declaration and
can be implemented in the class.
As for Example:
Public interface IStudnet
{
String Roll
{
get;
set;
}
String
FirstName
{
get;
set;
}
String
LastName
{
get;
set;
}
String
GetStudentDetails();
String
SaveStudentDetails ();
}
Below are the few
main difference between Abstract Class and Interface
a. In abstract
class method can have definition as well as declaration also. But Interface
should have only declarations.
b. All the Methods
are Public as default and don’t have any access Modifier Controls in interface,
whereas for abstract class we can have access modifier for methods.
c. Abstract class
can have constructor or destructor, whereas interface not.
d. Abstract class
can’t be part of multiple inheritance and we can implement multiple interface.
What do you mean by
String objects are immutable?
String objects are immutable as its state cannot be modified
once created. Every time when we perform any operation like add, copy, replace,
and case conversion or when we pass a string object as a parameter to a method
a new object will be created.
Example:
String str = "ABC";
str.Replace("A","X");
Here Replace() method will not change data that
"str" contains, instead a new string object is created to hold data
"XBC" and the reference to this object is returned by Replace()
method.
So in order to point str to this object we need to write
below line.
str = str.Replace("A","X");
Now the new object is assigned to the variable str. earlier
object that was assigned to str will take care by garbage collector as this one
is no longer in used.
What is dll hell
problem in .NET and how it will solve?
Ans: Dll hell, is kind of conflict that occurred previously,
due to the lack of version supportability of dll for (within) an application
.NET Framework provides operating system with a global
assembly cache. This cache is a repository for all the .net components that are
shared globally on a particular machine. When a .net component installed onto
the machine, the global assembly cache looks at its version, its public key and
its language information and creates a strong name for the component. The
component is then registered in the repository and indexed by its strong name,
so there is no confusion between the different versions of same component, or
DLL
What is a Partial
class?
Ans: Instead of defining an entire class, you can split the
definition into multiple classes by using partial class keyword. When the
application compiled, c# compiler will group all the partial classes together
and treat them as a single class. There are a couple of good reasons to use
partial classes. Programmers can work on different parts of classes without needing
to share same physical file
Ex:
Public partial class employee
{
Public void somefunction()
{
}
}
Public partial class employee
{
Public void function ()
{
}
}
What is difference
between constants, read-only and, static?
Constants: The value can’t be changed
Read-only: The value will be initialized only once from the
constructor of the class.
Static: Value can be initialized once.
What is the cross
page post backing?
Asp.Net 2.0 fixed this with built-in features that allowed
us to easily send information from one page to another.
Button control has property PostBackUrl that can be set to
URL of any page in our ASP.Net WebSite where we want to transfer all form
values to.
Along with that Asp.Net 2.0 Page class has a property
PreviousPage that allows us to get reference to the Page object that initiated
the postback (in other words to get the actual reference to the Page object of
the aspx page on which user clicked the Submit button on a HTML form).
So for example lets create two sample pages in our Web
Application:
SourcePage.aspx
DestinationPage.aspx
In SoucePage in Html form we will put two TextBox controls
(one for First Name and one for Last Name) and one Button component and set its PostBackUrl property to
"~/DestinationPage.aspx".
SourcePage.aspx:
<form
id="form1" runat="server">
<div>
First
Name: <asp:TextBox ID="FirstName"
runat="server"></asp:TextBox><br />
Last
Name: <asp:TextBox ID="LastName"
runat="server"></asp:TextBox><br /><br />
<asp:Button ID="Button1" runat="server"
Text="Submit To Destination Page"
PostBackUrl="~/CrossPagePostbacks/DestinationPage.aspx" />
</div>
</form>
When our user clicks the Submit button, all the values from the
HTML Form on SourcePage.aspx will be transfered to the DestinationPage.aspx and
we will also be able to get reference to the SourcePage.aspx in our
DestinationPage with the PreviousPage property like this:
So in our DestinationPage.aspx.cs code-behind we can easily
access two TextBox controls on SourcePage.aspx and show them in two label
controls like this:
protected void
Page_Load(object sender, EventArgs e)
{
// first check
if we had a cross page postback
if (
(PreviousPage != null) && (PreviousPage.IsCrossPagePostBack) )
{
Page
previousPage = PreviousPage;
TextBox
firstName = (TextBox)previousPage.FindControl("FirstName");
TextBox
lastName = (TextBox)previousPage.FindControl("LastName");
// we can
now use the values from TextBoxes and display them in two Label controls..
labelFirstName.Text = firstName.Text;
labelLastName.Text = lastName.Text;
}
}
You probably noticed that we first checked if PreviousPage
property of current page (DestinationPage.aspx) is NOT NULL, this is done to
avoid running our code in case that user opens our DestinationPage.aspx
directly, without running a cross page postback.
Also here we checked the another PreviousPage property
called IsCrossPagePostBack to see if we really had a CrossPagePostback.
(If Server.Transfer is used to redirect to this page,
IsCrossPagePostBack property will be set to FALSE.
TIP: We can be completely sure that we have a real CrossPagePostback ONLY IF:
Page.PreviousPage is NOT NULL,
PreviousPage.IsCrossPagePostback is true
This important to check to avoid errors in code.
Now this is very useful and i'm sure you are eager to use
this in your next project. But wait, we are not over yet!
Finding the controls on PreviousPage with FindControl method
and type-casting them from object to their real type is a little messy.
It feels like there must be a better solution for this!
And here it is: We can use the <%@ PreviousPageType %>
directive in the header of our DestinationPage.aspx like this
<%@
PreviousPageType VirtualPath="~/SourcePage.aspx" %>
to declare our previous page type, and then we can access
Public properties of the PreviousPage without typecasting.
Now all we need to do is to create some public properties on
our SourcePage.aspx.cs to expose data/Controls we want to the destionation
page:
public partial
class SourcePage : System.Web.UI.Page
{
public string
FormFirstName
{
get {
return FirstName.Text; }
}
public string
FormLastName
{
get {
return LastName.Text; }
}
}
And then we can change the Page_Load code in our
DestinationPage.aspx to much cleaner code like this:
protected void
Page_Load(object sender, EventArgs e)
{
// first check
if we had a cross page postback
if (
(PreviousPage != null) && (PreviousPage.IsCrossPagePostBack) )
{
SourcePage
prevPage = PreviousPage;
// we can
now use the values from textboxes and display them in two Label controls..
labelFirstName.Text = prevPage.FormFirstName;
labelLastName.Text = prevPage.FormLastName;
}
}
SourcePage type used in the code is offcourse name of the
partial class defined is SourcePage.aspx.cs that inherits System.Web.UI.Page
that is automatically created for us when we created new WebForm in
VisualStudio.
This code is much cleaner and easier to follow, there is no
ugly typecasting, just simple property values to use to retrieve the data from
previous page.
When should you use
Abstract Class vs Interface while programming?
Ans: When we want
that sub class must implement all the methods of base class. In such a
situation we will implement the interface. In the other hand when we want only
some method of base class in our sub class then use base class as abstract
class.
What is the
difference between application exception and system exception?
Ans: The difference between application exception and system
exception is that system exceptions are thrown by CLR and application
exceptions are thrown by applications.
What is the
difference between authorization and authentication?
Ans: Authorization is a process of allowing or denying
resources to particular user or record
Declaration of authorization is
<authorization>
<allow users=”Suresh, Sanjay”/>
<deny users=”Ramana, Rakesh”>
</authorization>
Sometimes authorization allows the unauthorized persons at
that time we will use
<deny users=”?”/>
Authentication means
Authentication is a process where we identify the
credentials of user i.e. username, password and create an identity to mention
user as an authenticated.
What is the use of
n-tier architecture and 3-tier architecture?
Check this article for 3-tier architecture 3 tier
architecture example in asp.net
How to get the
version of the assembly?
Ans: lbltxt.text=Assembly.
GetExecutingAssembly().GetName().Version.ToString();
What is the location
of Global Assembly Cache on the system?
Ans: c:\Windows\assembly
What is the serialization?
Ans: Serialization is a process of converting object into a
stream of bites.
What is
synchronization?
Ans: The mechanism needed to block one thread access to the
data. If the data is being accessed by another thread.
Synchronization can be accessed by using system.monitor
class
A monitor class methods are enter, exit, pulse for this lock
statement is also used
Suppose if we need to synchronize some data at that time we
need to place that data in this block
Lock
{
}
Whatever the data has been placed into the lock block that
data has been blocked
What are the thread
priority levels?
Ans: Thread priority levels are five types
0 - Zero
level
1 - Below
Normal
2 - Normal
3 - Above
Normal
4 - Highest
By Default priority level is 2
What is the
difference between .tostring(), Convert.tostring()?
Ans: The basic difference between them is “Convert” function
handles NULLS while
“.ToString()” does not it will throw a NULL reference
exception error. So as a good coding
practice using “convert” is always safe.
What is Collation?
Ans: Collation refers to a set of rules that determine how
the data is sorted and compared.
What is the
difference between Primary key and unique key?
Ans: Primary key does not allow the null values but unique
key allows one null value.
Primary key will create clustered index on column but unique
key will create non-clustered index by default.
How many web.config
files are there in 1 project?
Ans: There might be multiple web.config files for a single
project depending on the hierarchy of folders inside the root folder of the
project, so for each folder we can use one web.config file
What is the
difference between throw and throw ex?
What is the
difference between view state and hidden field?
Ans: viewstate is secured hidden field is insecure
Viewstate will store large amount of data but hidden filed
will store small amount of data.
What is the
difference between binary serialization and xml serialization?
What is the
Difference between read only and constant variables?
Ans: Read only can assign the values at runtime only.
Constant will assign the values at compile time only.
We cannot modify the both variable values.
What is static
keyword in .Net?
Ans: Static is same as constant variable but we can change
the value of static variable and we can access the variables without creating
any instances
What is the use of
business logic layer in 3-tier architecture in .net?
Ans: Though a web site could talk to the data access layer
directly, it usually goes through another layer called the business layer. The
business layer is vital in that it validates the input conditions before
calling a method from the data layer. This ensures the data input is correct
before proceeding, and can often ensure that the outputs are correct as well.
This validation of input is called business rules, meaning the rules that the
business layer uses to make “judgments” about the data.
However, business rules don’t only apply to data validation;
these rules apply to any calculations or any other action that takes place in
the business layer. Normally, it’s best to put as much logic as possible in the
business layer, which makes this logic reusable across applications.
One of the best reasons for reusing logic is that
applications that start off small usually grow in functionality. For instance,
a company begins to develop a web site, and as they realize their business
needs, they later decide to add a smart client application and windows service
to supplement the web site. The business layer helps move logic to a central
layer for “maximum reusability.”
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