Arunprakash's Blog

21 August 2012

SQL SERVER – Query to Find Seed Values, Increment Values and Current Identity Column value of a table

SQL SERVER – Query to Find Seed Values, Increment

Values and Current Identity Column value of a table

SELECT IDENT_SEED(TABLE_NAME) AS Seed,
IDENT_INCR(TABLE_NAME) AS Increment,
IDENT_CURRENT(TABLE_NAME) AS Current_Identity,
TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES
WHERE OBJECTPROPERTY(OBJECT_ID(TABLE_NAME), 'TableHasIdentity') = 1
AND TABLE_TYPE = 'BASE TABLE' and
TABLE_NAME='MSubject' -- [Table name]

For all the table in Database:

SELECT IDENT_SEED(TABLE_NAME) AS Seed,
IDENT_INCR(TABLE_NAME) AS Increment,
IDENT_CURRENT(TABLE_NAME) AS Current_Identity,
TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES
WHERE OBJECTPROPERTY(OBJECT_ID(TABLE_NAME), 'TableHasIdentity') = 1
AND TABLE_TYPE = 'BASE TABLE'

7 August 2012

Lamda expression in C#

Lamda expression in C#

A lambda expression is an anonymous function that can contain expressions and statements, and can be used to create delegates or expression tree types.

All lambda expressions use the lambda operator =>, which is read as "goes to".

The left side of the lambda operator specifies the input parameters (if any) and the right side holds the expression or statement block. The lambda expression x => x * x is read "x goes to x times x."

This expression can be assigned to a delegate type as follows:

delegate int del(int i);
static void Main(string[] args)
{
    del myDelegate = x => x * x;
    int j = myDelegate(5); //j = 25
}

To create an expression tree type:

using System.Linq.Expressions;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Expression myET = x = > gt; x * x;


The =>; operator has the same precedence as assignment (=) and is right-associative.

Lambdas are used in method-based LINQ queries as arguments to standard query operator methods such as Where.

6 August 2012

Anonymous Types in C#

Anonymous Types in C#

Anonymous types provide a convenient way to encapsulate a set of read-only properties into a single object without having to explicitly define a type first.

The following example shows an anonymous type that is initialized with two properties named Amount and Message.

var v = new { Amount = 108, Message = "Hello" };

// Rest the mouse pointer over v.Amount and v.Message in the following
// statement to verify that their inferred types are int and string.
Console.WriteLine(v.Amount + v.Message);

In the following example, the names of the properties of the anonymous type are Color and Price.

var productQuery = 
    from prod in products
    select new { prod.Color, prod.Price };

foreach (var v in productQuery)
{
    Console.WriteLine("Color={0}, Price={1}", v.Color, v.Price);
}

11 July 2012

String vs string in c#

String vs string in C#

we use either the keyword string or String .

Is both String and string same in C# ?

string is just an alias name for the class System.String which means both has the same functionality.
The IL code generated for both of them is also same .
Note that string is a keyword , but String isn’t which lets you create an variable with the name String like

Another interesting thing is we can also declare variable name as String

String String = "Arun Prakash";
MessageBox.Show(String);

If you declare the variable name as string, Error occured

String string = " Arun Prakash";
MessageBox.Show(string);

Use of Using Statement in C#

Use of Using Statement in C#

In C#, using Keyword is used in two different ways and are hence referred to differently.

As a Directive
In this usage, the "using" keyword can be used to include a namespace in your program. (Mostly used)

As a Statement
Using can also be used in a block of code to dispose an IDisposable objects.

SqlConnection connection = new SqlConnection("connection string");

SqlCommand cmd = new SqlCommand("SELECT * FROM SomeTable", connection);

SqlDataReader reader = cmd.ExecuteReader();

connection.Open();

if (reader != null)

{

while (reader.Read())

{

//do something

}

reader.Close(); // close the reader

connection.Close(); // close the connection

Disadvantages of the above code:

If any exception occurs inside while block it throws exception, the connection.close() process will not executed due to the exception. To avoid this situation, we can take the help of the try....catch... finally block by closing the connection inside the finally block or inside the catch block.

Advantages of the below code:

"Using" keyword takes the parameter of type IDisposable. Whenever you are using any IDisposable type

object you should use the "using" keyword to handle automatically when it should close or dispose.

Internally using keyword calls the Dispose() method to dispose the IDisposable object.

using (SqlConnection connection = new SqlConnection("connection string"))

{

connection.Open();

using (SqlCommand cmd = new SqlCommand("SELECT * FROM SomeTable", connection))

{

using (SqlDataReader reader = cmd.ExecuteReader())

{

if (reader != null)

{

while (reader.Read())

{

//do something

}

} // reader closed and disposed up here

} // command disposed here

} //connection closed and disposed here

7 July 2012

Cloud Computing

Cloud Computing

Cloud computing is the delivery of computing and storage capacity ^[1] as a service ^[2] to a heterogeneous community of end-recipients. The name comes from the use of a cloud-shaped symbol^[3] as an abstraction for the complex infrastructure it contains in system diagrams^[4]. Cloud computing entrusts services with a user's data, software and computation over a network.

There are three types of cloud computing:^[5]

Using Infrastructure as a Service, users rent use of servers (as many as needed during the rental period) provided by one or more cloud providers.

Using Platform as a Service, users rent use of servers and the system software to use in them.

Using Software as a Service, users also rent application software and databases. The cloud providers manage the infrastructure and platforms on which the applications run.

End users access cloud-based applications through a web browser or a light-weight desktop or mobile app while the business software and user's data are stored on servers at a remote location.

Proponents claim that cloud computing allows enterprises to get their applications up and running faster, with improved manageability and less maintenance, and enables IT to more rapidly adjust resources to meet fluctuating and unpredictable business demand.

Cloud computing relies on sharing of resources to achieve coherence and economies of scale similar to a utility (like theelectricity grid) over a network (typically the Internet). At the foundation of cloud computing is the broader concept of converged infrastructure and shared services.