Base Page For Detecting Session Timeout in ASP.Net/C#

In this tutorial we will be going over how to create a base page class to handle your sessions. The number one question I get asked time and time again is how to manage sessions, and how to detect if a session has expired. Back in the days before .Net things were a little more complicated when it came to solving this riddle, but with the advent of the .Net Framework 2.0 a new class was introduced, the HttpSessionState Class, which is a member of the System.Web.SessionState Namespace. The new HttpSessionState Class gives us access to session state items and other lifetime management methods.

One of the items in the HttpSessionState class we will be looking at is the IsNewSession Property. This property lets us know whether the current session was created wtih the current request, or if it was an existing session. This is invaluable as we can use it to determine if the users session had expired or timed out. The IsNewSession Property is more robust and advanced then simply checking if the session is null because it takes into account a session timeout as well.

In this tutorial we will create a base page class that we can inherit all our pages from, and in this class we will check the status of the users session in the Page.OnInit Method. The OnOnit Method fires before the Page Load Event, giving us the ability to check the session before the page is actually rendered. So lets get to some code.

The first thing we will need to do, as with any class you create, is to make sure we have a reference to the appropriate Namespaces. For our class we need but 2 Namespaces, the System.Web.UI Namespace and the System Namespace, so lets add them to our class.

NOTE: All Namespace references need to come before the declaration of your class.

using System;
using System.Web.UI;

Now we are going to declare our class, the class in this example is named SessionCheck, and it looks like

public class SessionCheck: System.Web.UI.Page
{

}

You will notice that our base class, which we will be inheriting from, inherits from the System.Web.UI.Page class. Doing this gives us access to all the methods, properties and events of the Page  class. In our base class we will have a single property, this will be the property that will hold the URL we want the user to redirect to if there is a problem with their session. We make this property static  so we can access it without having to create an instance of the class. We dont want to have to do this because we are inheriting from it. 
This is our property


/// 

/// property vcariable for the URL Property
/// 
private static string _url;

/// 

/// property to hold the redirect url we will
/// use if the users session is expired or has
/// timed out.
/// 
public static string URL
{
    get { return _url; }
    set { _url = value; }
}
Now that we have our property out of the way, we will look at the only  of our base class, the OnInit which we will override in order to add our ow functionality. In 
this method we will also initialize our base class, you do that with line


base.OnInit(e);
In our OnInit Method we will first check to
 see if the current session is null. If the session is null we then will
 check the IsNewSession Property to see if 
this session was created in this request. If we determine the session is
 a new session, we will then cal upon the Headers 
Property of the HttpRequest
 Class, which is located in the System.Web
 Namespace.



In our OnInit Method we will first check to
 see if the current session is null. If the session is null we then will
 check the IsNewSession Property to see if 
this session was created in this request. If we determine the session is
 a new session, we will then cal upon the Headers 
Property of the HttpRequest
 Class, which is located in the System.Web
 Namespace.



The Header we are retrieving is the Cookie Header. Once we have this, we will first 
check to see if it's null, if it's not null we will look for the value ASP.Net_SessionId. Now if we make it this far, and
 that cookie exists, we know the session has timed out, so we will then 
redirect the user to our redirect page, which is set with the URL Property. So lets take a look at our new OnInit Method:


override protected void OnInit(EventArgs e)
{
    //initialize our base class (System.Web,UI.Page)
    base.OnInit(e);
    //check to see if the Session is null (doesnt exist)
    if (Context.Session != null)
    {
        //check the IsNewSession value, this will tell us if the session has been reset.
        //IsNewSession will also let us know if the users session has timed out
        if (Session.IsNewSession)
        {
           //now we know it's a new session, so we check to see if a cookie is present
            string cookie = Request.Headers["Cookie"];
            //now we determine if there is a cookie does it contains what we're looking for
            if ((null != cookie) && (cookie.IndexOf("ASP.NET_SessionId") >= 0))
            {
                //since it's a new session but a ASP.Net cookie exist we know
                //the session has expired so we need to redirect them
                Response.Redirect("Default.aspx?timeout=yes&success=no");
            }
        }
    }
}

That's it, we have completed our base class which all our web forms will inherit from, allowing us to keep an eye on the users session. Now that we have the class completed we need to use it. Before it can be affected we need to do 1 of 2 things

• Add EnableSessionState = true to the @Page directive on all pages that will inherit from our base class or
• Add the following line to the section of our web.config file:

That's it, we have completed our base class which all our web forms will inherit from, allowing us to keep an eye on the users session. Now that we have the class completed we need to use it. Before it can be affected we need to do 1 of 2 things

• Add EnableSessionState = true to the @Page directive on all pages that will inherit from our base class or
• Add the following line to the section of our web.config file

Number 2 on that list will enable session state on all pages in the web. If you dont access session items in each of your pages, this might be overkill. Next we will need to inherit from our base class. Doing this will give our web form the following declaration

public partial class _Default : SessionCheck
{

}

Then in the Page_Load Event we will set the redirect URL for our base class

protected void Page_Load(object sender, EventArgs e)
{
    SessionCheck.URL = "Default.aspx";
}

Now here is the entire base page in its entirety

//   A Base Page class for detecting session time outs
//
//   This program is free software: you can redistribute it and/or modify
//   it under the terms of the GNU General Public License as published by
//   the Free Software Foundation, either version 3 of the License, or
//   (at your option) any later version.
//
//   This program is distributed in the hope that it will be useful,
//   but WITHOUT ANY WARRANTY; without even the implied warranty of
//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//   GNU General Public License for more details.
//
//   You should have received a copy of the GNU General Public License
//   along with this program.  If not, see .
//*****************************************************************************************

using System;
using System.Web.UI;

/// 

/// This is a custom "base page" to inherit from which will be used
/// to check the session status. If the session has expired or is a timeout
/// we will redirect the user to the page we specify. In the page you use
/// to inherit this from you need to set EnableSessionState = True
/// 
public class SessionCheck : System.Web.UI.Page
{
    /// 

    /// property vcariable for the URL Property
    /// 
    private static string _redirectUrl;

    /// 

    /// property to hold the redirect url we will
    /// use if the users session is expired or has
    /// timed out.
    /// 
    public static string RedirectUrl
    {
        get { return _redirectUrl; }
        set { _redirectUrl = value; }
    }

        public SessionCheck()
        {
        _redirectUrl = string.Empty;
        }

    override protected void OnInit(EventArgs e)
    {
        //initialize our base class (System.Web,UI.Page)
        base.OnInit(e);
        //check to see if the Session is null (doesnt exist)
        if (Context.Session != null)
        {
            //check the IsNewSession value, this will tell us if the session has been reset.
            //IsNewSession will also let us know if the users session has timed out
            if (Session.IsNewSession)
            {
               //now we know it's a new session, so we check to see if a cookie is present
                string cookie = Request.Headers["Cookie"];
                //now we determine if there is a cookie does it contains what we're looking for
                if ((null != cookie) && (cookie.IndexOf("ASP.NET_SessionId") >= 0))
                {
                    //since it's a new session but a ASP.Net cookie exist we know
                    //the session has expired so we need to redirect them
                    Response.Redirect("Default.aspx?timeout=yes&success=no");
                }
            }
        }
    }
}

And there you have it, a custom base class that you can use to detect session timeouts. I hope you found this tutorial helpful and useful, and thank you for reading

Happy Coding!

Reading and Writing XML in C#

In this article, you will see how to read and write XML documents in Microsoft .NET using C# language. First, I will discuss XML .NET Framework Library namespace and classes. Then, you will see how to read and write XML documents. In the end of this article, I will show you how to take advantage of ADO.NET and XML .NET model to read and write XML documents from relational databases and vice versa.

Introduction to Microsoft .NET XML Namespaces and Classes Before start working with XML document
in .NET Framework, It is important to know about .NET namespace and classes provided by .NET Runtime Library. .NET provides five namespace - System.Xml, System.Xml.Schema, System.Xml.Serialization, System.Xml.XPath, and System.Xml.Xsl to support XML classes. The System.Xml namespace contains major XML classes. This namespace contains many classes to read and write XML documents. In this article, we are going to concentrate on reader and write class. These reader and writer classes are used to read and write XMl documents. These classes are - XmlReader, XmlTextReader, XmlValidatingReader, XmlNodeReader, XmlWriter, and XmlTextWriter. As you can see there are four reader and two writer classes. The XmlReader class is an abstract bases classes and contains methods and properties to read a document. The Read method reads a node in the stream. Besides reading functionality, this class also contains methods to navigate through a document nodes. Some of these methods are MoveToAttribute,  MoveToFirstAttribute, MoveToContent, MoveToFirstContent, MoveToElement and  MoveToNextAttribute. ReadString, ReadInnerXml, ReadOuterXml, and ReadStartElement are more read methods. This class also has a method Skip to skip current node and move to next one. We'll see these methods in our sample example. The XmlTextReader, XmlNodeReader and XmlValidatingReader classes are derived from XmlReader class. As their name explains, they are used to read text, node, and schemas. The XmlWrite class contains functionality to write data to XML documents. This class provides many write method to write XML document items. This class is base class for XmlTextWriter class, which we'll be using in our sample example. The XmlNode class plays an important role. Although, this class represents a single node of XML but that could be the root node of an XML document and could represent the entire file. This  class is an abstract base class for many useful classes for inserting, removing, and replacing nodes, navigating through the document. It also contains properties to get a parent or child, name, last child, node type and more. Three major classes derived from XmlNode are XmlDocument, XmlDataDocument and XmlDocumentFragment. XmlDocument class represents an XML document and provides methods and properties to load and save a document. It also provides functionality to add XML items such as attributes, comments, spaces, elements, and new nodes.

The Load and LoadXml methods can be used to load XML documents and Save method to save a document respectively. XmlDocumentFragment class represents a document fragment, which can be used to add to a document. The XmlDataDocument class provides methods and properties to work with ADO.NET data set objects. In spite of above discussed classes, System.Xml namespace contains more classes. Few of them are XmlConvert, XmlLinkedNode, and XmlNodeList. Next namespace in Xml series is  System.Xml.Schema.

It classes  to work with XML schemas such XmlSchema, XmlSchemaAll, XmlSchemaXPath, XmlSchemaType. The System.Xml.Serialization namespace contains classes that are used to serialize objects into XML format documents or streams. The System.Xml.XPath Namespce contains XPath related classes to use XPath specifications. This namespace has following classes  -XPathDocument, XPathExression, XPathNavigator, and XPathNodeIterator. With the help of XpathDocument, XpathNavigator provides a fast
navigation though XML documents. This class contains many Move methods to move through a document. The System.Xml.Xsl namespace contains classes to work with XSL/T transformations. Reading XML Documents In my sample application, I'm using books.xml to read and display its data through XmlTextReader. This file comes with VS.NET samples. You can search this on your machine and change the path of the file in the following line: XmlTextReader textReader = new XmlTextReader("C:\\books.xml"); Or you can use any XML file. The XmlTextReader, XmlNodeReader and XmlValidatingReader classes
are derived from XmlReader class. Besides XmlReader methods and properties, these classes also contain members to read text, node, and schemas respectively. I am using XmlTextReader class to read an XML file. You read a file by passing file name as a parameter in constructor. XmlTextReader textReader = new XmlTextReader("C:\\books.xml"); After creating an instance of XmlTextReader, you call Read method to start reading the document. After read method is called, you can read all information and data stored in a document. XmlReader class has properties such as Name, BaseURI, Depth, LineNumber an so on. List 1 reads a document and displays a node information using these properties. About Sample Example 1 In this sample example, I read an XML file using XmlTextReader and call Read method to read its node one by one until end of file and display the contents to the console output. Sample Example 1.

using System;

using System.Xml;

namespace ReadXml1

{

    class Class1

    {

        static void Main(string[] args)

        {

            // Create an isntance of XmlTextReader and call Read method to read the file

            XmlTextReader textReader = new XmlTextReader("C:\\books.xml");

            textReader.Read();

            // If the node has value

            while (textReader.Read())

            {

                // Move to fist element

                textReader.MoveToElement();

                Console.WriteLine("XmlTextReader Properties Test");

                Console.WriteLine("===================");

                // Read this element's properties and display them on console

                Console.WriteLine("Name:" + textReader.Name);

                Console.WriteLine("Base URI:" + textReader.BaseURI);

                Console.WriteLine("Local Name:" + textReader.LocalName);

                Console.WriteLine("Attribute Count:" + textReader.AttributeCount.ToString());

                Console.WriteLine("Depth:" + textReader.Depth.ToString());

                Console.WriteLine("Line Number:" + textReader.LineNumber.ToString());

                Console.WriteLine("Node Type:" + textReader.NodeType.ToString());

                Console.WriteLine("Attribute Count:" + textReader.Value.ToString());

            }

        }

    }

}

The NodeType property of XmlTextReader is important when you want to know the content type of a document. The XmlNodeType enumeration has a member for each type of XML item such as Attribute, CDATA, Element, Comment, Document, DocumentType, Entity, ProcessInstruction, WhiteSpace and so on. List 2 code sample reads an XML document, finds a node type and writes information at the end with how many node types a document has. About Sample Example 2 In this sample example, I read an XML file using XmlTextReader and call Read method to read its node one by one until end of the file. After reading a node, I check its NodeType property to find the node and write node contents to the console and keep track of number of particular type of nodes. In the end, I display total number of different types of nodes in the document. Sample Example 2.

using System;

using System.Xml;

namespace ReadingXML2

{

    class Class1

    {

        static void Main(string[] args)

        {

            int ws = 0;

            int pi = 0;

            int dc = 0;

            int cc = 0;

            int ac = 0;

            int et = 0;

            int el = 0;

            int xd = 0;

            // Read a document

            XmlTextReader textReader = new XmlTextReader("C:\\books.xml");

            // Read until end of file

            while (textReader.Read())

            {

                XmlNodeType nType = textReader.NodeType;

                // If node type us a declaration

                if (nType == XmlNodeType.XmlDeclaration)

                {

                    Console.WriteLine("Declaration:" + textReader.Name.ToString());

                    xd = xd + 1;

                }

                // if node type is a comment

                if (nType == XmlNodeType.Comment)

                {

                    Console.WriteLine("Comment:" + textReader.Name.ToString());

                    cc = cc + 1;

                }

                // if node type us an attribute

                if (nType == XmlNodeType.Attribute)

                {

                    Console.WriteLine("Attribute:" + textReader.Name.ToString());

                    ac = ac + 1;

                }

                // if node type is an element

                if (nType == XmlNodeType.Element)

                {

                    Console.WriteLine("Element:" + textReader.Name.ToString());

                    el = el + 1;

                }

                // if node type is an entity\

                if (nType == XmlNodeType.Entity)

                {

                    Console.WriteLine("Entity:" + textReader.Name.ToString());

                    et = et + 1;

                }

                // if node type is a Process Instruction

                if (nType == XmlNodeType.Entity)

                {

                    Console.WriteLine("Entity:" + textReader.Name.ToString());

                    pi = pi + 1;

                }

                // if node type a document

                if (nType == XmlNodeType.DocumentType)

                {

                    Console.WriteLine("Document:" + textReader.Name.ToString());

                    dc = dc + 1;

                }

                // if node type is white space

                if (nType == XmlNodeType.Whitespace)

                {

                    Console.WriteLine("WhiteSpace:" + textReader.Name.ToString());

                    ws = ws + 1;

                }

            }

            // Write the summary

            Console.WriteLine("Total Comments:" + cc.ToString());

            Console.WriteLine("Total Attributes:" + ac.ToString());

            Console.WriteLine("Total Elements:" + el.ToString());

            Console.WriteLine("Total Entity:" + et.ToString());

            Console.WriteLine("Total Process Instructions:" + pi.ToString());

            Console.WriteLine("Total Declaration:" + xd.ToString());

            Console.WriteLine("Total DocumentType:" + dc.ToString());

            Console.WriteLine("Total WhiteSpaces:" + ws.ToString());

        }

    }

}

Writing XML Documents XmlWriter class contains the functionality to write to XML documents. It is an abstract base class used through XmlTextWriter and XmlNodeWriter classes. It contains methods and properties to write to XML documents. This class has several Writexxx method to write every type of item of an XML document. For example, WriteNode, WriteString, WriteAttributes, WriteStartElement, and WriteEndElement are some of them. Some of these methods are used in a start and end pair. For example,
to write an element, you need to call WriteStartElement then write a string followed by WriteEndElement.          

Besides many methods, this class has three properties. WriteState, XmlLang, and XmlSpace. The WriteState gets and sets the state of the XmlWriter class. Although, it's not possible to describe all the Writexxx methods here, let's see some of them. First thing we need to do is create an instance of XmlTextWriter using its  constructor. XmlTextWriter has three overloaded constructors, which can take a string, stream, or a TextWriter as an argument. We'll pass a string (file name) as an argument, which we're going to create in C:\ root. In my sample example, I create a file myXmlFile.xml in C:\\ root directory. // Create a new file in C:\\ dir XmlTextWriter textWriter = new XmlTextWriter("C:\\myXmFile.xml", null) ; After creating an instance, first
thing you call us WriterStartDocument. When you're done writing, you call WriteEndDocument and TextWriter's Close method. textWriter.WriteStartDocument(); textWriter.WriteEndDocument(); textWriter.Close(); The WriteStartDocument and WriteEndDocument methods open and close a document for writing. You must have to open a document before start writing to it.  WriteComment method writes comment to a document. It takes only one string type of argument. WriteString method writes a string to a document. With the help of WriteString, WriteStartElement and WriteEndElement methods pair can be used  to write an element to a document. The WriteStartAttribute and WriteEndAttribute pair writes an attribute. WriteNode is more write method, which writes an XmlReader to a document as a node of the document. For example, you can use WriteProcessingInstruction and WriteDocType methods to write a ProcessingInstruction and DocType items of a document. //Write the ProcessingInstruction node string PI= "type='text/xsl' href='book.xsl'" textWriter.WriteProcessingInstruction("xml-stylesheet", PI); //'Write the DocumentType node textWriter.WriteDocType("book", Nothing, Nothing, ""); The below sample example summarizes all these methods and creates a new xml document with some items in it such as elements, attributes, strings, comments and so on. See Listing 5-14. In this sample example, we create a new xml file c:\xmlWriterText.xml. In this sample example, We create a new xml file c:\xmlWriterTest.xml using XmlTextWriter: After that, we add comments and elements to the document using Writexxx methods. After that we read our books.xml xml file using XmlTextReader and add its elements to xmlWriterTest.xml using XmlTextWriter. About Sample Example 3 In this sample example, I create a new file myxmlFile.xml using XmlTextWriter and use its various write methods to write XML items. Sample Example 3.

using System;

using System.Xml;

namespace ReadingXML2

{

    class Class1

    {

        static void Main(string[] args)

        {

            // Create a new file in C:\\ dir

            XmlTextWriter textWriter = new XmlTextWriter("C:\\myXmFile.xml", null);

            // Opens the document

            textWriter.WriteStartDocument();

            // Write comments

            textWriter.WriteComment("First Comment XmlTextWriter Sample Example");

            textWriter.WriteComment("myXmlFile.xml in root dir");

            // Write first element

            textWriter.WriteStartElement("Student");

            textWriter.WriteStartElement("r", "RECORD", "urn:record");

            // Write next element

            textWriter.WriteStartElement("Name", "");

            textWriter.WriteString("Student");

            textWriter.WriteEndElement();

            // Write one more element

            textWriter.WriteStartElement("Address", ""); textWriter.WriteString("Colony");

            textWriter.WriteEndElement();

            // WriteChars

            char[] ch = new char[3];

            ch[0] = 'a';

            ch[1] = 'r';

            ch[2] = 'c';

            textWriter.WriteStartElement("Char");

            textWriter.WriteChars(ch, 0, ch.Length);

            textWriter.WriteEndElement();

            // Ends the document.

            textWriter.WriteEndDocument();

            // close writer

            textWriter.Close();

        }

    }

}

Using XmlDocument The XmlDocument class represents an XML document. This class provides similar methods and properties we've discussed earlier in this article. Load and LoadXml are two useful methods of this class. A Load method loads XML data from a string, stream, TextReader or XmlReader. LoadXml method loads XML document from a specified string. Another useful method of this class is Save. Using Save method you can write XML data to a string, stream, TextWriter or XmlWriter. About Sample Example 4 This tiny sample example pretty easy to understand. We call LoadXml method of XmlDocument to load an XML fragment and call Save to save the fragment as an XML file. Sample Example 4.

//Create the XmlDocument. XmlDocument doc = new XmlDocument();
doc.LoadXml(("Tommyex")); //Save the document to a file. doc.Save("C:\\std.xml");

You can also use Save method to display contents on console if you pass Console.Out as a arameter. For example: doc.Save(Console.Out); About Sample Example 5 Here is one example of how to load an XML document using XmlTextReader. In this sample example, we read books.xml file using XmlTextReader and call its Read method. After that we call XmlDocumetn's Load method to load XmlTextReader contents to XmlDocument and call Save method to save the document. Passing Console.Out as a Save method
argument displays data on the console Sample Example 5. XmlDocument doc = new XmlDocument();
//Load the the document with the last book node.
XmlTextReader reader = new XmlTextReader("c:\\books.xml");
reader.Read(); // load reader doc.Load(reader); // Display contents on the console
doc.Save(Console.Out); Writing Data from a database to an XML Document Using XML and ADO.NET mode, reading a database and writing to an XML document and vice versa is not a big deal. In this section of this article, you will see how to read a database table's data and write the contents to an XML document. The DataSet class provides method to read a relational database table and write this table to an XML file.
You use WriteXml method to write a dataset data to an XML file. In this sample example, I have used commonly used Northwind database comes with Office 2000 and later versions. You can use any database you want. Only thing you need to do is just chapter the connection string and SELECT SQ L query. About Sample Example 6  In this sample, I reate a data adapter object and selects all records of Customers table. After that I can fill method to fill a dataset from the data adapter. In this sample example,I have used OldDb data provides. You need to add reference to the Syste.Data.OldDb namespace to use OldDb data adapters in your program. As you can see from Sample Example 6, first I create a connection with northwind database using OldDbConnection. After that I create a data adapter object by passing a SELECT SQL query and connection. Once you have a data adapter, you can fill a dataset object using Fill method of the data adapter. Then you can WriteXml method of DataSet, which creates an XML document and write its contents to the XML document. In our sample, we read Customers table records and write DataSet contents to OutputXml.Xml file in C:\ dir. Sample Example 6.
using System; using System.Xml; using System.Data; using System.Data.OleDb; namespace ReadingXML2 { class Class1 { static void Main(string[] args) { // create a connection OleDbConnection con = new OleDbConnection(); con.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=C:\\Northwind.mdb"; // create a data adapter OleDbDataAdapter da = new OleDbDataAdapter("Select * from Customers", con); // create a new dataset DataSet ds = new DataSet(); // fill dataset da.Fill(ds, "Customers"); // write dataset contents to an xml file by calling WriteXml method ds.WriteXml("C:\\OutputXML.xml"); } } }

.NET Framework Library provides a good support to work with XML documents. The XmlReader,
XmlWriter and their derived classes contains methods and properties to read and write XML documents. With the help of the XmlDocument and XmlDataDocument classes, you can read entire document. The Load and Save method of XmlDocument loads a reader or a file and saves document respectively. ADO.NET provides functionality to read a database and write its contents to the XML document using data providers and a DataSet object.

Main Differences between ASP.NET 3.5 and ASP.NET 4.0

As we all know, ASP.NET 3.5 has introduced with the following main new features

1) AJAX integration
2) LINQ
3) Automatic Properties
4) Lambda expressions

I hope it would be useful for everyone to know about the differences about asp.net 3.5 and its next version asp.net 4.0

Because of space consumption I’ll list only some of them here.

1) Client Data access:

ASP.NET 3.5: There is no direct method to access data from client side. We can go for any of these methods

1) Pagemethods of script manager
2) ICallbackEventHandler interface
3) XMLHttphanlder component

ASP.NET 4.0: In this framework there is an inbuilt feature for this. Following are the methods to implement them.

1) Client data controls
2) Client templates
3) Client data context

i.e we can access the data through client data view & data context objects from client side.

2) Setting Meta keyword and Meta description:

Meta keywords and description are really useful for getting listed in search engine.

ASP.NET 3.5: It has a feature to add meta as following tag

&ltmeta name="keywords" content="These, are, my, keywords" /> 
  &ltmeta name="description" content="This is the description of my page" /> 

ASP.NET 4.0: Here we can add the keywords and description in Page directives itself as shown below.

< %@ Page Language="C#"  CodeFile="Default.aspx.cs" 
  Inherits="_Default" 
  Keywords="Keyword1,Key2,Key3,etc" 
  Description="description" %>

3) Enableviewstage property for each control

ASP.NET 3.5: this property has two values “True” or “false”

ASP.NET 4.0: ViewStateMode property takes an enumeration that has three values: Enabled, Disabled, and Inherit.
Here inherit is the default value for child controls of a control.

4) Setting Client IDs

Some times ClientID property creates head ach for the programmers.

ASP.NET 3.5: We have to use ClientID property to find out the id which is dynamically generated

ASP.NET 4.0: The new ClientIDMode property is introduced to minimize the issues of earlier versions of ASP.NET.

It has following values.

AutoID – Same as ASP.NET 3.5
Static – There won’t be any separate clientid generated at run time
Predictable-These are used particularly in datacontrols. Format is like clientIDrowsuffix with the clientid vlaue
Inherit- This value specifies that a control's ID generation is the same as its parent. 


--
happy programming.

.Net Memory Management & Garbage Collection

The Microsoft .NET common language runtime requires that all resources be allocated from the managed heap. Objects are automatically freed when they are no longer needed by the application.
When a process is initialized, the runtime reserves a contiguous region of address space that initially has no storage allocated for it. This address space region is the managed heap. The heap also maintains a pointer. This pointer indicates where the next object is to be allocated within the heap. Initially, the pointer is set to the base address of the reserved address space region.
Garbage collection in the Microsoft .NET common language runtime environment completely absolves the developer from tracking memory usage and knowing when to free memory. However, you’ll want to understand how it works. So let’s do it.
Topics Covered
We will cover the following topics in the article

1. Why memory matters
2. .Net Memory and garbage collection
3. Generational garbage collection
4. Temporary Objects
5. Large object heap & Fragmentation
6. Finalization
7. Memory problems

1) Why Memory Matters

Insufficient use of memory can impact

• Performance
• Stability
• Scalability
• Other applications

Hidden problem in code can cause

• Memory leaks
• Excessive memory usage
• Unnecessary performance overhead

2) .Net Memory and garbage collection

.Net manages memory automatically

• Creates objects into memory blocks(heaps)
• Destroy objects no longer in use

Allocates objects onto one of two heaps

• Small object heap(SOH) – objects < 85k
• Large object heap(LOH) – objects >= 85k

You allocate onto the heap whenever you use the “new” keyword in code
Small object heap (SOH)

• Allocation of objects < 85k – Contiguous heap – Objects allocated consecutively
• Next object pointer is maintained – Objects references held on Stack, Globals, Statics and CPU register
• Objects not in use are garbage collected

Figure-1

Next, How GC works in SOH?
GC Collect the objects based on the following rules:

• Reclaims memory from “rootless” objects
• Runs whenever memory usage reaches certain thresholds
• Identifies all objects still “in use”
  
  
  • Has root reference
  • Has an ancestor with a root reference
  
  
• Compacts the heap
  
  
  • Copies “rooted” objects over rootless ones
  • Resets the next object pointer
  
  
• Freezes all execution threads during GC
  
  
  • Every GC runs it   hit the performance of your app
  
  

Figure-2

3) Generational garbage collection

Optimizing Garbage collection

• Newest object usually dies quickly
• Oldest object tend to stay alive
• GC groups objects into Generations
  
  
  • Short lived – Gen 0
  • Medium – Gen 1
  • Long Lived – Gen 2
  
  
• When an object survives a GC it is promoted to the next generation
• GC compacts Gen 0 objects most often
• The more the GC runs the bigger the impact on performance

Figure-3

Figure-4

Here object C is no longer referenced by any one so when GC runs it get destroyed & Object D will be moved to the Gen 1 (see figure-5). Now Gen 0 has no object, so when next time when GC runs it will collect object from Gen 1.

Figure-5

Figure-6

Here when GC runs it will move the object D & B to Gen 2 because it has been referenced by Global objects & Static objects.
Figure-7


Here when GC runs for Gen 2 it will find out that object A is no longer referenced by anyone so it will destroy it & frees his memory. Now Gen 2 has only object D & B.
Garbage collector runs when

• Gen 0 objects reach ~256k
• Gen 1 objects reach ~2Meg
• Gen 2 objects reach ~10Meg
• System memory is low

Most objects should die in Gen 0.
Impact on performance is very high when Gen 2 run because

• Entire small object heap is compacted
• Large object heap is collected

4) Temporary objects

• Once allocated objects can’t resize on a contiguous heap
• Objects such as strings are Immutable
  
  
  
  • Can’t be changed, new versions created instead
  • Heap fills with temporary objects
  
  

Let us take example to understand this scenario.
Figure – 8

After the GC runs all the temporary objects are destroyed.
Figure–9

5) Large object heap & Fragmentation

Large object heap (LOH)

• Allocation of object >=85k
• Non contiguous heap
  
  
  • Objects allocated using free space table
  
  
  
• Garbage collected when LOH Threshold Is reached
• Uses free space table to find where to allocate
• Memory can become fragmented

Figure-10

After object B is destroyed free space table will be filled with a memory address which has been available now.
Figure-11


Now when you create new object, GC will check out which memory area is free or available for our new object in LOH. It will check out the Free space table & allocate object where it fit.
Figure-12

6) Object Finalization

• Disk, Network, UI resources need safe cleanup after use by .NET classes
• Object finalization guarantees cleanup code will be called before collection
• Finalizable object survive for at least 1 extra GC & often make it to Gen 2
• Finalizable classes have a
  
  
  • Finalize method(c# or vb.net)
  • C++ style destructor (c#)
  
  

Here are the guidelines that help you to decide when to use Finalize method:

• Only implement Finalize on objects that require finalization. There are performance costs associated with Finalize methods.
• If you require a Finalize method, you should consider implementing IDisposable to allow users of your class to avoid the cost of invoking the Finalize method.
• Do not make the Finalize method more visible. It should be protected, not public.
• An object’s Finalize method should free any external resources that the object owns. Moreover, a Finalize method should release only resources that are held onto by the object. The Finalize method should not reference any other objects.
• Do not directly call a Finalize method on an object other than the object’s base class. This is not a valid operation in the C# programming language.
• Call the base.Finalize method from an object’s Finalize method.

Note: The base class’s Finalize method is called automatically with the C# and the Managed Extensions for C++ destructor syntax.
Let see one example to understand how the finalization works.
Each figure itself explain what is going on & you can clearly see how the finalization works when GC run.

Figure-13

Figure-14

Figure-15

Figure-16

Figure-17


For more information on Finalization refer the following links:
http://www.object-arts.com/docs/index.html?howdofinalizationandmourningactuallywork_.htm
http://blogs.msdn.com/cbrumme/archive/2004/02/20/77460.aspx
How to minimize overheads
Object size, number of objects, and object lifetime are all factors that impact your application’s allocation profile. While allocations are quick, the efficiency of garbage collection depends (among other things) on the generation being collected. Collecting small objects from Gen 0 is the most efficient form of garbage collection because Gen 0 is the smallest and typically fits in the CPU cache. In contrast, frequent collection of objects from Gen 2 is expensive. To identify when allocations occur, and which generations they occur in, observe your application’s allocation patterns by using an allocation profiler such as the CLR Profiler.
You can minimize overheads by:

• Avoid Calling GC.Collect
• Consider Using Weak References with Cached Data
• Prevent the Promotion of Short-Lived Objects
• Set Unneeded Member Variables to Null Before Making Long-Running Calls
• Minimize Hidden Allocations
• Avoid or Minimize Complex Object Graphs
• Avoid Preallocating and Chunking Memory

Read more: http://www.guidanceshare.com/wiki/.NET_2.0_Performance_Guidelines_-_Garbage_Collection

7) Common Memory Problems

• Excessive RAM footprint
  
  
  • App allocates objects too early or for too long using more memory than needed
  • Can affect other app on system
  
  
• Excessive temporary object allocation
  
  
  • Garbage collection runs more frequently
  • Executing threads freeze during garbage collection
  
  
• Memory leaks
  
  
  
  • Overlooked root references keep objects alive (collections, arrays, session state, delegates/events etc)
  • Incorrect or absent finalization can cause resource leaks
  
  

References & other useful articles related to this topic:

• Link 1
• Link 2
• Link 3

Hope this help

Backing Up MySQL Database

Backing Up MySQL Database

MySQL database backup can be accomplished in two ways:

a) Copying the raw mysql database files &
b) Exporting tables to text files

Copying the MySQL database files

MySQL uses the same table format on different platforms, so it's possible to copy MySQL table and index files from one platform and use them on another without any difficulties (assuming, of course, that you're using the same version of MySQL on both platforms).

Exporting tables to text files

The MySQLDump is handy utility that can be used to quickly backup the MySQL Database to the text files. To use the MySQLDump utility it is required to logon to the System running the MySQL Databse. You can use Telnet to remotely logon to the system if you don't have the physical access to the machine.

The syntax for the command is as follows.

mysqldump -u [Username] -p [password] [databasename] > [backupfile.sql]
[username] - this is your database username
[password]- this is the password for your database
[databasename] - the name of your database
[backupfile.sql] - the filename for your database backup

Let's discuss the example of backing up MySQL Database named "accounts" into text file accounts.sql. Here are the scenarios of taking the backup assuming that both user name and password of the database is "admin".

a) Taking the full backup of all the tables including the data.
 

Use the following command to accomplish this:
mysqldump -u admin -p admin accounts > accounts.sql

b) Taking the backup of table structures only.
 

Use the following command to accomplish this:
mysqldump -u admin -p admin --no-data accounts > accounts.sql

c) Taking the backup data only.
 

Use the following command to accomplish this:
mysqldump -u admin -p admin --no-create-info accounts > accounts.sql

Restoring MySQL Database

Restoring the MySQL is very easy job. You can use the following to command to restore the accounts database from accounts.sql backup file.

mysql - u admin -p admin accounts < accounts.sql

In this tutorial you learned how to take the backup of your MySQL Database and restore the same in the event of some database crash or on some other machine.

-----------

Enjoy Programming

Uploading Multiple Files in ASP.NET 2.0

In ASP.NET We can upload more than one file using the following classes:

HttpFileCollection
HttpPostedFile
Request.Files
System.IO.Path

HttpFileCollection:

HttpFileCollection will provide access to the files uploaded by a client.

HttpPostedFile:

HttpPostedFile will provide access to individual files uploaded by a client. Through this class we can access the content and properties of each individual file, and read and save the files.

Request.Files :

The Request.Files will return collection of all files uploaded by user and store them inside the HttpFileCollection.

Follow these steps mentioned below to do so:

Step 1:

Drag and drop multiple (in our case four) FileUpload controls on to the designer.

Step 2:

Drop a Button control and rename it to “Upload”

<asp:Button ID=”btnUpload” runat=”server” Text=”Upload” />

Step 3:

Double click the Upload Button to add an event hander to the code behind.

protected void btnUpload_Click(object sender, EventArgs e)
{

}

Step 4: Import the System.IO namespace.

using System.IO;

Step 5:

Use the ‘HttpFileCollection’ class to retrieve all the files that are uploaded. Files are encoded and transmitted in the content body using multipart MIME format with an HTTP Content-Type header. ASP.NET extracts
this information from the content body into individual members of an HttpFileCollection.

The code would look as follows:

protected void btnUpload_Click(object sender, EventArgs e)
{
try
{
// Get the HttpFileCollection
HttpFileCollection hfc = Request.Files;
for (int i = 0; i < hfc.Count; i++)
{
HttpPostedFile hpf = hfc[i];
if (hpf.ContentLength > 0)
{
hpf.SaveAs(Server.MapPath(”MyFiles”) + “\\” +
Path.GetFileName(hpf.FileName));

}
}
}
catch (Exception ex)
{
// Handle your exception here
}

}

Some important points to consider while uploading

1.    To save a file to the server, the account associated with ASP.NET must have sufficient permissions on the folder, where the files are being uploaded. This would usually be the ‘ASPNET’ account for Windows XP or a similar OS. In Windows Server 2003, the account used is ‘NETWORKSERVICE’. So you would be required to explicitly grant write permissions to these accounts on the folder.

2.    While uploading the files to a remote server, the default ASPNET user account used by ASP.NET does not have network permissions by default. The solution is to either give the account such permissions or
use impersonation to have it run under a different account that has the permissions.

3.    By default, you can upload no more than 4096 KB (4 MB) of data. However there is a workaround for this limitation. You can change the maximum file size by changing the maxRequestLength attribute of the
httpRuntime element in the web.config file. You can also increase the ‘executionTimeout’. By default it is 110 seconds. I would encourage you to experiment with the other attributes of the httpRuntime element.

<configuration>
<system.web>
<httpRuntime
executionTimeout=”200″
maxRequestLength=”8192″
requestLengthDiskThreshold=”256″
useFullyQualifiedRedirectUrl=”false”
minFreeThreads=”8″
minLocalRequestFreeThreads=”4″
appRequestQueueLimit=”5000″
enableKernelOutputCache=”true”
enableVersionHeader=”true”
requireRootedSaveAsPath=”true”
enable=”true”
shutdownTimeout=”90″
delayNotificationTimeout=”5″
waitChangeNotification=”0″
maxWaitChangeNotification=”0″
enableHeaderChecking=”true”
sendCacheControlHeader=”true”
apartmentThreading=”false”/>
</system.web>
</configuration>

References

There are a number of good resources I referred to, for this article. A few of them are:

http://www.wrox.com/WileyCDA/Section/id-292160.html
http://msdn2.microsoft.com/en-US/library/aa479405.aspx
http://msdn2.microsoft.com/en-us/library/system.web.httpfilecollection.aspx

Some Sql Server Interview Questions

* Difference between Set and Select
Ans:
1) Set is a ANSI standard for variable assignment.
   Select is a Non-ANSI standard when assigning variables.We can assign only one variable at a time

2) We can assign multiple variable at a time.When assigning from a query that returns more than one value, SET will fail with an error.
   When assigning from a query that returns more than one value, SELECT will assign the last value returned by the query and hide the fact that the query returned

* What is Network Packet Size in SQL
Ans:
NPS(Network Packet Size) is the size of the TDS (tabular data stream) packets used to communicate between your applications and your relational database engine and default packet size is 4 kilobytes and its manily depends on network packet size configuration option.


* How many different locks in SQL SERVER
Ans:
(1)Intent
(2)shared
(3)Update
(4)Exclusive
(5)Schema
(6)Bulk Update

* Diffrence between temp table and table variable
Ans:
(1)Temp Tables are created in the SQL Server TEMPDB database and therefore require more IO resources and locking. Table Variables and Derived Tables are created in memory.

(2)Temp Tables will generally perform better for large amounts of data that can be worked on using parallelism whereas Table Variables are best used for small amounts of data (I use a rule of thumb of 100 or less rows) where parallelism would not provide a significant performance improvement.

(3)You cannot use a stored procedure to insert data into a Table Variable or Derived Table. For example, the following will work: INSERT INTO #MyTempTable EXEC dbo.GetPolicies_sp whereas the following will generate an error: INSERT INTO @MyTableVariable EXEC dbo.GetPolicies_sp.

(4)Derived Tables can only be created from a SELECT statement but can be used within an Insert, Update, or Delete statement.

(5) In order of scope endurance, Temp Tables extend the furthest in scope, followed by Table Variables, and finally Derived Tables.

* What is Cursor
Ans:
  Cursor is a database object used by applications to manipulate data in a set on a row-by-row basis, instead of the typical SQL commands that operate on all the rows in the set at one time. For example, you can use cursor to include a list of all user databases and make multiple operations against each database by passing each database name as a variable

* Write some disadvantage of Cursor
Ans:
  Cursor plays there row quite nicely but although there are some disadvantage of Cursor . Because we know cursor doing roundtrip it will make network line busy and also make time consuming methods. First of all select query gernate output and after that cursor goes one by one so roundtrip happen.Another disadvange of cursor are ther are too costly because they require lot of resources and temporary storage so network is quite busy.

* Can you tell me the difference between DELETE and TRUNCATE commands
Ans:
  Delete command removes the rows from a table based on the condition that we provide with a WHERE clause. Truncate will actually remove all the rows from a table and there will be no data in the table after we run the truncate command.

How to pad a numeric type column with leading zeros?

Execute the following Microsoft SQL Server T-SQL example scripts to demonstrate SQL padding of numbers and strings with leading and trailing zeros as well as with other designated characters, and techniques
for removing (trim) leading zeros. 

-- SQL Server leading zero - T-SQL padding numbers - lpad tsql - sql pad zero

SELECT ListPrice,

  Padded=RIGHT('0000000000' + CONVERT(VARCHAR,ListPrice), 10)

FROM AdventureWorks2008.Production.Product WHERE ListPrice > 0.0

------------

-- T SQL pad leading zeros - transact sql leading zeros

SELECT ProductID, ReorderPoint = REPLACE(STR(ReorderPoint, 6), SPACE(1), '0')

FROM AdventureWorks2008.Production.Product

/* ProductID            ReorderPoint

      1                 000750

      2                 000750

      3                 000600  */

 ------------

-- SQL Server leading zero - SQL leading zeros - sql server pad leading zero

USE AdventureWorks2008;

DECLARE @Number int = 789

SELECT RIGHT ('000000'+ CAST (@Number AS varchar), 6)

-- 000789

------------

USE AdventureWorks;

-- SQL padding salary pay rate money data type with leading zeroes

-- SQL left pad number - prefix number with zeros - sql server leading zero

-- SQL convert number to text - cast number to varchar string

SELECT EmployeeID,

       Rate,

       PaddedRate = RIGHT(REPLICATE('0',8) + CAST(Rate AS VARCHAR(8)),8)

FROM   HumanResources.EmployeePayHistory
/* Partial results

EmployeeID        Rate              PaddedRate

1                 12.45             00012.45

2                 13.4615           00013.46

3                 43.2692           00043.27

*/


-- SQL zero padding ListPrice money data type - t sql leading zero

-- SQL left pad - T-SQL string concatenation - sql concat

-- SQL convert number to string - pad numeric with zeros

SELECT ProductID,

       ListPrice,

       PaddedListPrice = RIGHT(REPLICATE('0', 8) + CAST(ListPrice AS VARCHAR(8)),8)

FROM Production.Product

/* Results sample

ProductID               ListPrice               PaddedListPrice

965                     742.35                  00742.35

*/


-- SQL month leading zero - sql pad month number with zero

SELECT RIGHT('0' + convert(varchar(2), month(GetDate())), 2)

-- 06
----------

-- trim leading zeros - sql trim leading zeros - remove leading zeros sql

USE AdventureWorks2008;

DECLARE @num  varchar(32)= '00091234560'

SELECT      right(@num, len(@num)+1 - patindex('%[^0]%', @num))

-- 91234560

------------

-- SQL pad numeric data type - SQL pad digits - transact sql leading zeros

-- SQL pad with leading zeroes - append leading zeros - T-SQL top function

-- SQL pad with trailing zeroes - MSSQL append trailing zeros

-- SQL cast money to numeric - cast numeric to string - mssql newid function

SELECT TOP (5)

      ProductName = Name,

      ListPrice = RIGHT(REPLICATE('0', 10)

      + CAST(CAST(ListPrice AS NUMERIC(9,3)) AS VARCHAR) ,10)  

FROM AdventureWorks.Production.Product

ORDER BY NEWID()

/* ProductName                      ListPrice

LL Mountain Frame - Black, 40       000249.790

HL Touring Frame - Yellow, 46       001003.910

Bike Wash - Dissolver               000007.950

Metal Sheet 7                       000000.000

HL Road Frame - Red, 56             001431.500

*/

----------


-- PAD leading zeros function - sql server leading zeros - UDF

USE AdventureWorks2008;

GO

CREATE FUNCTION fnPadNumber

               (@n      DECIMAL(26,2),

                @length TINYINT)

RETURNS VARCHAR(32)

AS

  BEGIN

    RETURN ( replicate('0',@length - len(convert(VARCHAR(32),@n))) +

             convert(VARCHAR(32),@n))

  END

GO


SELECT dbo.fnPadNumber(1234567890.12,16)

-- 0001234567890.12
------------

-- T SQL computed column zero padding - sql generate alphanumeric sequence

USE tempdb; -- SQL Server 2008 T-SQL

CREATE TABLE Celebrity (

  ID           INT    IDENTITY ( 1 , 1 )    PRIMARY KEY,

  CelebrityID  AS 'CEL' + RIGHT('0000' + CAST( ID as varchar),5), -- computed column

  FirstName    VARCHAR(32),

  LastName     VARCHAR(32),

  ModifiedDate DATE    DEFAULT getdate())

GO


INSERT Celebrity

      (FirstName,

       LastName)

VALUES('Jennifer','Aniston'),

      ('Drew','Barrymore'),

      ('Diana','Princess of Wales'),

      ('Tom','Jones'),

      ('Lucille','Ball'),

      ('Frank','Sinatra'),

      ('Elvis','Presley')


SELECT * FROM   Celebrity

GO

-- CelebrityID is zero padded alphanumeric sequence

/* 

ID    CelebrityID       FirstName  LastName          ModifiedDate

1     CEL00001          Jennifer    Aniston          2012-07-04

2     CEL00002          Drew        Barrymore        2012-07-04

3     CEL00003          Diana       Princess of Wales 2012-07-04

4     CEL00004          Tom         Jones             2012-07-04

5     CEL00005          Lucille     Ball              2012-07-04

6     CEL00006          Frank       Sinatra          2012-07-04

7     CEL00007          Elvis       Presley          2012-07-04

*/

-- Cleanup demo

DROP TABLE Celebrity

GO
------------

-- SQL removing leading zeros when no spaces in string - trimming Leading Zeros

USE AdventureWorks2008;

DECLARE @NumberString varchar(16)='000000246'

SELECT REPLACE(LTRIM(REPLACE(@NumberString, '0', ' ')), ' ', '0')

-- 246

------------

-- SQL remove leading zeros - sql trim leading zeros - numeric test

DECLARE @StringWithLeadingZeros    VARCHAR(12) = '000000654321'

SELECT CAST(CAST(@StringWithLeadingZeros AS INT) AS VARCHAR(10))

WHERE ISNUMERIC (@StringWithLeadingZeros)=1

-- 654321

------------

-- LPAD & RPAD string scalar-valued user-defined functions (UDF)

USE AdventureWorks;

GO

-- Left pad string function

CREATE FUNCTION LPAD

               (@SourceString VARCHAR(MAX),

                @FinalLength  INT,

                @PadChar      CHAR(1))

RETURNS VARCHAR(MAX)

AS

  BEGIN

    RETURN

      (SELECT Replicate(@PadChar,@FinalLength - Len(@SourceString)) + @SourceString)

  END

GO


-- T-SQL Test left padding

SELECT LeftPaddedString = dbo.LPAD(Cast(84856 AS VARCHAR),12,'0')

GO

-- 000000084856


-- MSSQL right pad string function

CREATE FUNCTION RPAD

               (@SourceString VARCHAR(MAX),

                @FinalLength  INT,

                @PadChar      CHAR(1))

RETURNS VARCHAR(MAX)

AS

  BEGIN

    RETURN

      (SELECT @SourceString + Replicate(@PadChar,@FinalLength - Len(@SourceString)))

  END

GO


-- Test right padding

SELECT RightPaddedString = dbo.RPAD(Cast(84856 AS VARCHAR),12,'*')

GO

-- 84856*******

----------


-- Padding a money column with leading zeroes - sql convert leading zero

-- SQL convert money data type to string

SELECT PaddedUnitPrice = RIGHT(replicate('0',20) +

                         convert(varchar,UnitPrice,1), 20)

FROM Northwind.dbo.Products

/* Partial results


PaddedUnitPrice

00000000000000018.00

00000000000000019.00

00000000000000010.00

00000000000000022.00

*/


/**************** Zero padding other numeric data ****************/


-- SQL Server 2008 version featuring the LEFT function

-- SQL convert integer to text - convert integer to varchar

USE AdventureWorks2008;

DECLARE @InputNumber int = 522, @OutputLength tinyint = 12

DECLARE @PaddedString char(12)

SET @PaddedString = LEFT( replicate( '0', @OutputLength ),

    @OutputLength - len( @InputNumber ) ) + convert( varchar(12), @InputNumber)

SELECT PaddedNumber=@PaddedString

/* Result


PaddedNumber

000000000522

*/



-- SQL format currency and pad with leading spaces

-- SQL Server lpad to 9 characters

SELECT   TOP (3)  ProductName=Name,

                  Price=   CONVERT(char(9), ListPrice, 1)

FROM Production.Product

WHERE ListPrice > 0.0 ORDER BY Newid()

/*

ProductName                         Price

LL Touring Frame - Blue, 62           333.42

LL Road Seat Assembly                 133.34

Road-250 Red, 58                    2,443.35

*/

------------

-- Padding with zeroes in the middle of string

DECLARE @Number varchar(10)

SET @Number = '99999'

PRINT 'TRK' + REPLICATE('0', 12 - LEN(@Number)) + @Number

SELECT [Zero Padding]='TRK' + REPLICATE('0', 12 - LEN(@Number)) + @Number

-- Result: TRK000000099999


-- Applying the STUFF string function for zero padding

-- SQL convert integer data type to string

DECLARE @SerialNo int, @OutputSize tinyint

SET @OutputSize = 10

SET @SerialNo = 6543

SELECT PaddedSerialNo =  STUFF(replicate('0', @OutputSize),

    @OutputSize - len(@SerialNo)+1, len(@SerialNo), convert(varchar(9),@SerialNo))

-- Result: 0000006543

-- SQL pad integer with 0-s

-- SQL str function - numeric to character conversion

SELECT TOP 5

CAST(replace(str(ProductID,6),' ','0') AS char(6)) AS ProdID

FROM AdventureWorks.Production.Product

ORDER BY Name

/* Results

ProdID

000001

000879

000712

000003

000002

*/


-- SQL pad string with character

-- SQL create function

-- SQL user-defined function

CREATE FUNCTION dbo.fnLeftPadString (

      @Input VARCHAR(255),

      @PadChar CHAR(1),

      @LengthToPad TINYINT

      )

RETURNS VARCHAR(255) AS 

BEGIN

DECLARE @InputLen TINYINT

SET @InputLen = LEN(@Input)

RETURN

   CASE

      WHEN @InputLen < @LengthToPad

      THEN REPLICATE(@PadChar, @LengthToPad - @InputLen) + @Input

      ELSE @Input

   END -- CASE

END -- UDF

GO


-- SQL pad string – left padding - SQL left pad with asterisk

-- SQL check printing - SQL currency formatting

DECLARE @DollarAmount varchar(20)

SET @DollarAmount = '234.40'

SELECT PaddedString='$'+dbo.fnLeftPadString(@DollarAmount, '*', 10)

GO

-- Result: $****234.40


-- SQL currency formatting with asterisk-fill

DECLARE @Amount MONEY

SET @Amount = '3534.40'

SELECT CurrencyFormat = '$' + REPLACE(Convert(char(12),@Amount,1),' ','*')

-- $****3,534.40

SELECT      PaddedProductID =

                  dbo.fnLeftPadString (CONVERT(varchar, ProductID), '0', 6),

            ProductName=Name,

            ListPrice

FROM Production.Product

ORDER BY PaddedProductID

GO


/* Partial results


PaddedProductID         ProductName       ListPrice

000757                  Road-450 Red, 48  1457.99

000758                  Road-450 Red, 52  1457.99

000759                  Road-650 Red, 58  782.99

000760                  Road-650 Red, 60  782.99

000761                  Road-650 Red, 62  782.99

*/

----------

-- Generating tracking numbers

-- SQL pad zeroes

WITH cteSequence(SeqNo)

     AS (SELECT 1

         UNION ALL

         SELECT SeqNo + 1

         FROM   cteSequence

         WHERE  SeqNo < 1000000)

SELECT TOP 100 CAST(('TRK' + REPLICATE('0',

               7 - LEN(CAST(SeqNo AS VARCHAR(6)))) +

               CAST(SeqNo AS VARCHAR(6))) AS VARCHAR(10)) AS TrackingNo

FROM   cteSequence

OPTION (MAXRECURSION 0)

GO

/* Partial results


TrackingNo

TRK0000001

TRK0000002

TRK0000003

TRK0000004

TRK0000005

TRK0000006

TRK0000007

*/

----------

-- SQL server pad

-- SQL str function

-- SQL pad integer

-- SQL left pad

SELECT TOP (4) StaffName=LastName+', '+FirstName,

PaddedEmployeeID = REPLACE(STR(EmployeeID, 6, 0), ' ', '0')

FROM HumanResources.Employee e

INNER JOIN Person.Contact c

      ON e.ContactID = c.ContactID

ORDER BY NEWID()

/* Results


StaffName         PaddedEmployeeID

Dyck, Shelley     000214

Hines, Michael    000039

Ford, Jeffrey     000015

Caron, Rob        000168

*/


-- SQL asterisk padding

-- SQL pad with asterisk

-- SQL right pad

SELECT  TOP ( 2 * 2 )

              AddressID

            , City+REPLICATE('*', 20-len(City)) AS City

            , PostalCode

FROM AdventureWorks.Person.[Address]

WHERE LEN(City) <= 20

ORDER by NEWID()

GO

/*

AddressID   City                          PostalCode

13465       Imperial Beach******    91932

23217       Corvallis***********    97330

18548       Milwaukie***********    97222

24893       Goulburn************    2580

*/

------------

------------

-- SQL left pad any size string Alpha with any length string Beta

------------

-- SQL user-defined function - UDF - scalar-valued string function

-- T-SQL varchar(max)

USE AdventureWorks2008;

GO

CREATE FUNCTION fnMaxPad

               (@SourceString  VARCHAR(MAX),

                @PaddingString VARCHAR(MAX),

                @OutputLength  INT)

RETURNS VARCHAR(MAX)

AS

  BEGIN

    DECLARE  @WorkString VARCHAR(MAX) =

      ISNULL(REPLICATE(@PaddingString,@OutputLength - len(ISNULL(@SourceString,0))),

                            '') + @SourceString

    RETURN RIGHT(@WorkString, @OutputLength)

  END

GO


-- Execute UDF

SELECT TOP ( 5 ) [SQL Padding Demo] =

  dbo.fnMaxPad(CONVERT(VARCHAR,FLOOR(ListPrice)),'_/',21)

FROM     Production.Product

ORDER BY NEWID()

GO

/* Results


SQL Padding Demo

_/_/_/_/_/_/_/2443.00

/_/_/_/_/_/_/_/_/0.00

/_/_/_/_/_/_/_/147.00

/_/_/_/_/_/_/_/_/0.00

_/_/_/_/_/_/_/1003.00

*/

------------

-- SQL left pad unicode string Alpha with any length unicode string Beta

-- MSSQL pad international

-- SQL user-defined function - UDF - scalar-value function

-- T-SQL nvarchar(max)

USE AdventureWorks2008;

GO

CREATE FUNCTION fnMaxPadInternational

               (@SourceString  NVARCHAR(MAX),

                @PaddingString NVARCHAR(MAX),

                @OutputLength  INT)

RETURNS NVARCHAR(MAX)

AS

  BEGIN

    DECLARE  @WorkString NVARCHAR(MAX) =

      ISNULL(REPLICATE(@PaddingString,@OutputLength - len(ISNULL(@SourceString,0))),

                            '') + @SourceString

    

    RETURN RIGHT(@WorkString, @OutputLength)

  END

GO


-- Execute UDF

SELECT TOP ( 5 ) [SQL Padding Demo] =

dbo.fnMaxPadInternational(LEFT(Description,6),'_/',21)

FROM     Production.ProductDescription

ORDER BY NEWID()

GO

/* Results


SQL Padding Demo

/_/_/_/_/_/_/_/ล้อ ที่

/_/_/_/_/_/_/_/Roue d

/_/_/_/_/_/_/_/شوكة ط

/_/_/_/_/_/_/_/Each f

/_/_/_/_/_/_/_/Jeu de

*/

------------

Reference from sqlusa.com

How to configure SQL Server 2005 to allow remote connections?

To configure SQL Server 2005 to allow remote connections, complete all the following steps.
• Enable remote connections on the instance of SQL Server that you want to connect to from a remote computer.
• Turn on the SQL Server Browser service.
• Configure the firewall to allow network traffic that is related to SQL Server and to the SQL Server Browser service.

Enable remote connections for SQL Server 2005 Express

1. Click Start, point to Programs, point to Microsoft SQL Server 2005, point to Configuration Tools, and then click SQL Server Surface Area Configuration.
2. On the SQL Server 2005 Surface Area Configuration page, click Surface Area Configuration for Services and Connections.
3. On the Surface Area Configuration for Services and Connections page, expand Database Engine, click Remote Connections, click Local and remote connections, click the appropriate protocol to enable for your environment, and then click Apply.
Note Click OK when you receive the following message:
Changes to Connection Settings will not take effect until you restart the Database Engine service.
4. On the Surface Area Configuration for Services and Connections page, expand Database Engine, click Service, click Stop. wait until the MSSQLSERVER service stops, and then click Start to restart the MSSQLSERVER service.

Enable the SQL Server Browser service

1.Click Start, point to Programs, point to Microsoft SQL Server 2005, point to Configuration Tools, and then click SQL Server Surface Area Configuration.
2.On the SQL Server 2005 Surface Area Configuration page, click Surface Area Configuration for Services and Connections.
3.On the Surface Area Configuration for Services and Connections page, click SQL Server Browser, click Automatic for Startup type, and then click Apply.
Note When you click the Automatic option, the SQL Server Browser service starts automatically every time that you start Microsoft Windows.
4.Click Start, and then click OK.

Create exceptions in Windows Firewall

SQL Server 2005 uses an instance ID as part of the path when you install its program files. To create an exception for each instance of SQL Server, you must identify the correct instance ID. To obtain an instance ID, follow these steps:
1. Click Start, point to Programs, point to Microsoft SQL Server 2005, point to Configuration Tools, and then click SQL Server Configuration Manager.
2. In SQL Server Configuration Manager, click the SQL Server Browser service in the right pane, right-click the instance name in the main window, and then click Properties.
3. On the SQL Server Browser Properties page, click the Advanced tab, locate the instance ID in the property list, and then click OK.
To open Windows Firewall, click Start, click Run, type firewall.cpl, and then click OK.
Create an exception for SQL Server 2005 in Windows Firewall
To create an exception for SQL Server 2005 in Windows Firewall, follow these steps:
1. In Windows Firewall, click the Exceptions tab, and then click Add Program.
2. In the Add a Program window, click Browse.
3. Click the C:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\Binn\sqlservr.exe executable program, click Open, and then click OK.
Note The path may be different depending on where SQL Server 2005 is installed. MSSQL.1 is a placeholder for the instance ID that you obtained in step 3 of the previous procedure.
4. Repeat steps 1 through 3 for each instance of SQL Server 2005 that needs an exception.
Create an exception for the SQL Server Browser service in Windows Firewall
To create an exception for the SQL Server Browser service in Windows Firewall, follow these steps:
1. In Windows Firewall, click the Exceptions tab, and then click Add Program.
2. In the Add a Program window, click Browse.
3. Click the C:\Program Files\Microsoft SQL Server\90\Shared\sqlbrowser.exe executable program, click Open, and then click OK.

---
Hope this helps everyone.

Encryption & Decryption : ASCII encoding

The GetByteCount method determines how many bytes result in encoding a set of Unicode characters, and the GetBytes method performs the actual encoding.

Likewise, the GetCharCount method determines how many characters result in decoding a sequence of bytes, and the GetChars and GetString methods perform the actual decoding.

When selecting the ASCII encoding for your applications, consider the following:

    * The ASCII encoding is usually appropriate for protocols that require ASCII.
    * If your application requires 8-bit encoding, the UTF-8 encoding is recommended over the ASCII encoding. For the characters 0-7F, the results are identical, but use

of UTF-8 avoids data loss by allowing representation of all Unicode characters that are representable. Note that the ASCII encoding has an 8th bit ambiguity that can allow malicious use, but the UTF-8 encoding removes ambiguity about the 8th bit.

    * Previous versions of .NET Framework allowed spoofing by merely ignoring the 8th bit. The current version has been changed so that non-ASCII code points fall back during the decoding of bytes.

——————————————————————
Example of ASCII encoding
——————————————————————

SecurityClass.cs
————————–

public static string EnryptString(string strEncrypted)
{
byte[] b = System.Text.ASCIIEncoding.ASCII.GetBytes(strEncrypted);
string encryptedConnectionString = Convert.ToBase64String(b);
return encryptedConnectionString;
}

public static string DecryptString(string encrString)
{
byte[] b = Convert.FromBase64String(encrString);
string decryptedConnectionString = System.Text.ASCIIEncoding.ASCII.GetString(b);
return decryptedConnectionString;
}

Default.aspx.cs
———————

protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
string Password = “SandeepMRamani”;
lblOriginal.Text = Password;
lblEncryption.Text = SecurityClass.EnryptString(Password);
lblDecryption.Text = SecurityClass.DecryptString(lblEncryption.Text);
}
}

Default.aspx
——————

<div align=”center” style=”font-size:xx-large;”>
<h1> Encryption / Decryption Example </h1>
<hr />

Original String :
<asp:Label ID=”lblOriginal” style=”font-weight:bolder;” runat=”server” Text=”"></asp:Label>
<br />
Encrypted Text :
<asp:Label ID=”lblEncryption” style=”font-weight:bolder;” runat=”server” Text=”"></asp:Label>
<br />
Decrypted Text :
<asp:Label ID=”lblDecryption” style=”font-weight:bolder;” runat=”server” Text=”"></asp:Label>
<hr />
</div>

--

Happy programming