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Data warehouse is a repository of an organization’s electronically stored data. Data warehouses are designed to facilitate reporting and analysis.

This definition of the data warehouse focuses on data storage. However, the means to retrieve and analyze data, to extract, transform and load data, and to manage the data dictionary are also considered essential components of a data warehousing system. Many references to data warehousing use this broader context. Thus, an expanded definition for data warehousing includes business intelligence tools, tools to extract, transform, and load data into the repository, and tools to manage and retrieve metadata.

In contrast to data warehouses are operational systems that perform day-to-day transaction processing.
History of data warehousing

The concept of data warehousing dates back to the late 1980s [2] when IBM researchers Barry Devlin and Paul Murphy developed the “business data warehouse”. In essence, the data warehousing concept was intended to provide an architectural model for the flow of data from operational systems to decision support environments. The concept attempted to address the various problems associated with this flow - mainly, the high costs associated with it. In the absence of a data warehousing architecture, an enormous amount of redundancy of information was required to support the multiple decision support environments that usually existed. In larger corporations it was typical for multiple decision support environments to operate independently. Each environment served different users but often required much of the same data. The process of gathering, cleaning and integrating data from various sources, usually long existing operational systems (usually referred to as legacy systems), was typically in part replicated for each environment. Moreover, the operational systems were frequently reexamined as new decision support requirements emerged. Often new requirements necessitated gathering, cleaning and integrating new data from the operational systems that were logically related to prior gathered data.

Based on analogies with real-life warehouses, data warehouses were intended as large-scale collection/storage/staging areas for corporate data. Data could be retrieved from one central point or data could be distributed to “retail stores” or “data marts” that were tailored for ready access by users.

Key developments in early years of data warehousing were:

* 1960s - General Mills and Dartmouth College, in a joint research project, develop the terms dimensions and facts.[3]
* 1970s - ACNielsen and IRI provide dimensional data marts for retail sales.[3]
* 1983 - Teradata introduces a database management system specifically designed for decision support.
* 1988 - Barry Devlin and Paul Murphy publish the article An architecture for a business and information systems in IBM Systems Journal where they introduce the term “business data warehouse”.
* 1990 - Red Brick Systems introduces Red Brick Warehouse, a database management system specifically for data warehousing.
* 1991 - Prism Solutions introduces Prism Warehouse Manager, software for developing a data warehouse.
* 1991 - Bill Inmon publishes the book Building the Data Warehouse.
* 1995 - The Data Warehousing Institute, a for-profit organization that promotes data warehousing, is founded.
* 1996 - Ralph Kimball publishes the book The Data Warehouse Toolkit.
* 1997 - Oracle 8, with support for star queries, is released.

Data warehouse architecture

Architecture, in the context of an organization’s data warehousing efforts, is a conceptualization of how the data warehouse is built. There is no right or wrong architecture. The worthiness of the architecture can be judged in how the conceptualization aids in the building, maintenance, and usage of the data warehouse.

One possible simple conceptualization of a data warehouse architecture consists of the following interconnected layers:

Operational database layer
The source data for the data warehouse - An organization’s ERP systems fall into this layer.
Informational access layer
The data accessed for reporting and analyzing and the tools for reporting and analyzing data - Business intelligence tools fall into this layer. And the Inmon-Kimball differences about design methodology, discussed later in this article, have to do with this layer.
Data access layer
The interface between the operational and informational access layer - Tools to extract, transform, load data into the warehouse fall into this layer.
Metadata layer
The data directory - This is usually more detailed than an operational system data directory. There are dictionaries for the entire warehouse and sometimes dictionaries for the data that can be accessed by a particular reporting and analysis tool.

Normalized versus dimensional approach for storage of data

There are two leading approaches to storing data in a data warehouse - the dimensional approach and the normalized approach.

In the dimensional approach, transaction data are partitioned into either “facts”, which are generally numeric transaction data, or “dimensions”, which are the reference information that gives context to the facts. For example, a sales transaction can be broken up into facts such as the number of products ordered and the price paid for the products, and into dimensions such as order date, customer name, product number, order ship-to and bill-to locations, and salesperson responsible for receiving the order. A key advantage of a dimensional approach is that the data warehouse is easier for the user to understand and to use. Also, the retrieval of data from the data warehouse tends to operate very quickly. The main disadvantages of the dimensional approach are: 1) In order to maintain the integrity of facts and dimensions, loading the data warehouse with data from different operational systems is complicated, and 2) It is difficult to modify the data warehouse structure if the organization adopting the dimensional approach changes the way in which it does business.

In the normalized approach, the data in the data warehouse are stored following, to a degree, database normalization rules. Tables are grouped together by subject areas that reflect general data categories (e.g., data on customers, products, finance, etc.) The main advantage of this approach is that it is straightforward to add information into the database. A disadvantage of this approach is that, because of the number of tables involved, it can be difficult for users both to 1) join data from different sources into meaningful information and then 2) access the information without a precise understanding of the sources of data and of the data structure of the data warehouse.

These approaches are not mutually exclusive. Dimensional approaches can involve normalizing data to a degree.

Conforming information

Another important facet in designing a data warehouse is which data to conform and how to conform the data. For example, one operational system feeding data into the data warehouse may use “M” and “F” to denote sex of an employee while another operational system may use “Male” and “Female”. Though this is a simple example, much of the work in implementing a data warehouse is devoted to making similar meaning data consistent when they are stored in the data warehouse. Typically, extract, transform, load tools are used in this work.

Master Data Management has the aim of conforming data that could be considered “dimensions”.

Top-down versus bottom-up design methodologies

Bottom-up design

Ralph Kimball, a well-known author on data warehousing, [4] is a proponent of an approach frequently considered as bottom-up [5], to data warehouse design. In the so-called bottom-up approach data marts are first created to provide reporting and analytical capabilities for specific business processes. Data marts contain atomic data and, if necessary, summarized data. These data marts can eventually be unioned together to create a comprehensive data warehouse. The combination of data marts is managed through the implementation of what Kimball calls “a data warehouse bus architecture”.[6]

Business value can be returned as quickly as the first data marts can be created. Maintaining tight management over the data warehouse bus architecture is fundamental to maintaining the integrity of the data warehouse. The most important management task is making sure dimensions among data marts are consistent. In Kimball words, this means that the dimensions “conform”.

Top-down design

Bill Inmon, one of the first authors on the subject of data warehousing, has defined a data warehouse as a centralized repository for the entire enterprise.[6] Inmon is one of the leading proponents of the top-down approach to data warehouse design, in which the data warehouse is designed using a normalized enterprise data model. “Atomic” data, that is, data at the lowest level of detail, are stored in the data warehouse. Dimensional data marts containing data needed for specific business processes or specific departments are created from the data warehouse. In the Inmon vision the data warehouse is at the center of the “Corporate Information Factory” (CIF), which provides a logical framework for delivering business intelligence (BI) and business management capabilities. The CIF is driven by data provided from business operations

Inmon states that the data warehouse is:

Subject-oriented
The data in the data warehouse is organized so that all the data elements relating to the same real-world event or object are linked together.
Time-variant
The changes to the data in the data warehouse are tracked and recorded so that reports can be produced showing changes over time.
Non-volatile
Data in the data warehouse is never over-written or deleted - once committed, the data is static, read-only, and retained for future reporting.
Integrated
The data warehouse contains data from most or all of an organization’s operational systems and this data is made consistent.

The top-down design methodology generates highly consistent dimensional views of data across data marts since all data marts are loaded from the centralized repository. Top-down design has also proven to be robust against business changes. Generating new dimensional data marts against the data stored in the data warehouse is a relatively simple task. The main disadvantage to the top-down methodology is that it represents a very large project with a very broad scope. The up-front cost for implementing a data warehouse using the top-down methodology is significant, and the duration of time from the start of project to the point that end users experience initial benefits can be substantial. In addition, the top-down methodology can be inflexible and unresponsive to changing departmental needs during the implementation phases.[6]

Hybrid design

Over time it has become apparent to proponents of bottom-up and top-down data warehouse design that both methodologies have benefits and risks. Hybrid methodologies have evolved to take advantage of the fast turn-around time of bottom-up design and the enterprise-wide data consistency of top-down design.

Data warehouses versus operational systems

Operational systems are optimized for preservation of data integrity and speed of recording of business transactions through use of database normalization and an entity-relationship model. Operational system designers generally follow the Codd rules of data normalization in order to ensure data integrity. Codd defined five increasingly stringent rules of normalization. Fully normalized database designs (that is, those satisfying all five Codd rules) often result in information from a business transaction being stored in dozens to hundreds of tables. Relational databases are efficient at managing the relationships between these tables. The databases have very fast insert/update performance because only a small amount of data in those tables is affected each time a transaction is processed. Finally, in order to improve performance, older data are usually periodically purged from operational systems.

Data warehouses are optimized for speed of data retrieval. Frequently data in data warehouses are denormalised via a dimension-based model. Also, to speed data retrieval, data warehouse data are often stored multiple times - in their most granular form and in summarized forms called aggregates. Data warehouse data are gathered from the operational systems and held in the data warehouse even after the data has been purged from the operational systems.

Evolution in organization use of data warehouses

Organizations generally start off with relatively simple use of data warehousing. Over time, more sophisticated use of data warehousing evolves. The following general stages of use of the data warehouse can be distinguished:

Off line Operational Database
Data warehouses in this initial stage are developed by simply copying the data of an operational system to another server where the processing load of reporting against the copied data does not impact the operational system’s performance.
Off line Data Warehouse
Data warehouses at this stage are updated from data in the operational systems on a regular basis and the data warehouse data is stored in a data structure designed to facilitate reporting.
Real Time Data Warehouse
Data warehouses at this stage are updated every time an operational system performs a transaction (e.g., an order or a delivery or a booking.)
Integrated Data Warehouse
Data warehouses at this stage are updated every time an operational system performs a transaction. The data warehouses then generate transactions that are passed back into the operational systems.

Benefits of data warehousing

Some of the benefits that a data warehouse provides are as follows: [7][8]

* A data warehouse provides a common data model for all data of interest regardless of the data’s source. This makes it easier to report and analyze information than it would be if multiple data models were used to retrieve information such as sales invoices, order receipts, general ledger charges, etc.
* Prior to loading data into the data warehouse, inconsistencies are identified and resolved. This greatly simplifies reporting and analysis.
* Information in the data warehouse is under the control of data warehouse users so that, even if the source system data is purged over time, the information in the warehouse can be stored safely for extended periods of time.
* Because they are separate from operational systems, data warehouses provide retrieval of data without slowing down operational systems.
* Data warehouses can work in conjunction with and, hence, enhance the value of operational business applications, notably customer relationship management (CRM) systems.
* Data warehouses facilitate decision support system applications such as trend reports (e.g., the items with the most sales in a particular area within the last two years), exception reports, and reports that show actual performance versus goals.

Disadvantages of data warehouses

There are also disadvantages to using a data warehouse. Some of them are:

* Over their life, data warehouses can have high costs. The data warehouse is usually not static. Maintenance costs are high.
* Data warehouses can get outdated relatively quickly. There is a cost of delivering suboptimal information to the organization.
* There is often a fine line between data warehouses and operational systems. Duplicate, expensive functionality may be developed. Or, functionality may be developed in the data warehouse that, in retrospect, should have been developed in the operational systems and vice versa..

Sample Applications

Some of the applications data warehousing can be used for are:

* Credit card churn analysis
* Insurance fraud analysis
* Call record analysis
* Logistics management.

The future of data warehousing

Data warehousing, like any technology niche, has a history of innovations that did not receive market acceptance.[9]

A 2009 Gartner Group paper predicted these developments in business intelligence/data warehousing market .[10]

* Because of lack of information, processes, and tools, through 2012, more than 35 per cent of the top 5,000 global companies will regularly fail to make insightful decisions about significant changes in their business and markets.
* By 2012, business units will control at least 40 per cent of the total budget for business intelligence.
* By 2010, 20 per cent of organizations will have an industry-specific analytic application delivered via software as a service as a standard component of their business intelligence portfolio.
* In 2009, collaborative decision making will emerge as a new product category that combines social software with business intelligence platform capabilities.
* By 2012, one-third of analytic applications applied to business processes will be delivered through coarse-grained application mashups.

Unix Commands
How to use the unix commands listed below.
For more documentation on a command, consult a good book, or use the man pages. For example, for more information on grep, use the command man grep.

Contents

cat — for creating and displaying short files
chmod — change permissions
cd — change directory
cp — for copying files
date — display date
echo — echo argument
ftp — connect to a remote machine to download or upload files
grep — search file
head — display first part of file
ls — see what files you have
lpr — standard print command (see also print )
more — use to read files
mkdir — create directory
mv — for moving and renaming files
ncftp — especially good for downloading files via anonymous ftp.
print — custom print command (see also lpr )
pwd — find out what directory you are in
rm — remove a file
rmdir — remove directory
rsh — remote shell
setenv — set an environment variable
sort — sort file
tail — display last part of file
tar — create an archive, add or extract files
telnet — log in to another machine
wc — count characters, words, lines

cat

This is one of the most flexible Unix commands. We can use to create, view and concatenate files. For our first example we create a three-item English-Spanish dictionary in a file called “dict.”

% cat >dict
red rojo
green verde
blue azul
<control-D>
%

<control-D> stands for “hold the control key down, then tap ‘d’”. The symbol > tells the computer that what is typed is to be put into the file dict. To view a file we use cat in a different way:

% cat dict
red rojo
green verde
blue azul
%

If we wish to add text to an existing file we do this:
% cat >>dict
white blanco
black negro
<control-D>
%

Now suppose that we have another file tmp that looks like this:

% cat tmp
cat gato
dog perro
%

Then we can join dict and tmp like this:
% cat dict tmp >dict2

We could check the number of lines in the new file like this:

% wc -l dict2
8

The command wc counts things — the number of characters, words, and line in a file.
chmod

This command is used to change the permissions of a file or directory. For example to make a file essay.001 readable by everyone, we do this:

% chmod a+r essay.001

To make a file, e.g., a shell script mycommand executable, we do this

% chmod +x mycommand

Now we can run mycommand as a command.
To check the permissions of a file, use ls -l . For more information on chmod, use man chmod.
cd
Use cd to change directory. Use pwd to see what directory you are in.

% cd english
% pwd
% /u/ma/jeremy/english
% ls
novel poems
% cd novel
% pwd
% /u/ma/jeremy/english/novel
% ls
ch1 ch2 ch3 journal scrapbook
% cd ..
% pwd
% /u/ma/jeremy/english
% cd poems
% cd
% /u/ma/jeremy

Jeremy began in his home directory, then went to his english subdirectory. He listed this directory using ls , found that it contained two entries, both of which happen to be diretories. He cd’d to the diretory novel, and found that he had gotten only as far as chapter 3 in his writing. Then he used cd .. to jump back one level. If had wanted to jump back one level, then go to poems he could have said cd ../poems. Finally he used cd with no argument to jump back to his home directory.
cp
Use cp to copy files or directories.
% cp foo foo.2

This makes a copy of the file foo.
% cp ~/poems/jabber .

This copies the file jabber in the directory poems to the current directory. The symbol “.” stands for the current directory. The symbol “~” stands for the home directory.
date
Use this command to check the date and time.
% date
Fri Jan 6 08:52:42 MST 1995
echo
The echo command echoes its arguments. Here are some examples:

% echo this
this
% echo $EDITOR
/usr/local/bin/emacs
% echo $PRINTER
b129lab1

Things like PRINTER are so-called environment variables. This one stores the name of the default printer — the one that print jobs will go to unless you take some action to change things. The dollar sign before an environment variable is needed to get the value in the variable. Try the following to verify this:

% echo PRINTER
PRINTER

ftp
Use ftp to connect to a remote machine, then upload or download files. See also: ncftp

Example 1: We’ll connect to the machine fubar.net, then change director to mystuff, then download the file homework11:

% ftp solitude
Connected to fubar.net.
220 fubar.net FTP server (Version wu-2.4(11) Mon Apr 18 17:26:33 MDT 1994) ready.
Name (solitude:carlson): jeremy
331 Password required for jeremy.
Password:
230 User jeremy logged in.
ftp> cd mystuff
250 CWD command successful.
ftp> get homework11
ftp> quit

grep
Use this command to search for information in a file or files. For example, suppose that we have a file dict whose contents are

red rojo
green verde
blue azul
white blanco
black negro

Then we can look up items in our file like this;
% grep red dict
red rojo
% grep blanco dict
white blanco
% grep brown dict
%

Notice that no output was returned by grep brown. This is because “brown” is not in our dictionary file.

Grep can also be combined with other commands. For example, if one had a file of phone numbers named “ph”, one entry per line, then the following command would give an alphabetical list of all persons whose name contains the string “Fred”.

% grep Fred ph | sort
Alpha, Fred: 333-6565
Beta, Freddie: 656-0099
Frederickson, Molly: 444-0981
Gamma, Fred-George: 111-7676
Zeta, Frederick: 431-0987

The symbol “|” is called “pipe.” It pipes the output of the grep command into the input of the sort command.
For more information on grep, consult

% man grep
——————————————————————————–

head
Use this command to look at the head of a file. For example,

% head essay.001

displays the first 10 lines of the file essay.001 To see a specific number of lines, do this:

% head -n 20 essay.001

This displays the first 20 lines of the file.
ls
Use ls to see what files you have. Your files are kept in something called a directory.

% ls
foo letter2
foobar letter3
letter1 maple-assignment1
%

Note that you have six files. There are some useful variants of the ls command:

% ls l*
letter1 letter2 letter3
%

Note what happened: all the files whose name begins with “l” are listed. The asterisk (*) is the ” wildcard” character. It matches any string.
——————————————————————————–

lpr
This is the standard Unix command for printing a file. It stands for the ancient “line printer.” See

% man lpr

for information on how it works. See print for information on our local intelligent print command.
mkdir
Use this command to create a directory.
% mkdir essays

To get “into” this directory, do
% cd essays

To see what files are in essays, do this:
% ls

There shouldn’t be any files there yet, since you just made it. To create files, see cat or emacs.
more
More is a command used to read text files. For example, we could do this:

% more poems

The effect of this to let you read the file “poems “. It probably will not fit in one screen, so you need to know how to “turn pages”. Here are the basic commands:

q — quit more
spacebar — read next page
return key — read next line
b — go back one page
For still more information, use the command man more.

mv
Use this command to change the name of file and directories.

% mv foo foobar

The file that was named foo is now named foobar

ncftp
Use ncftp for anonymous ftp — that means you don’t have to have a password.

% ncftp ftp.fubar.net
Connected to ftp.fubar.net
> get jokes.txt

The file jokes.txt is downloaded from the machine ftp.fubar.net.

print
This is a moderately intelligent print command.
% print foo
% print notes.ps
% print manuscript.dvi

In each case print does the right thing, regardless of whether the file is a text file (like foo ), a postcript file (like notes.ps, or a dvi file (like manuscript.dvi. In these examples the file is printed on the default printer. To see what this is, do

% print

and read the message displayed. To print on a specific printer, do this:
% print foo jwb321
% print notes.ps jwb321
% print manuscript.dvi jwb321

To change the default printer, do this:
% setenv PRINTER jwb321
pwd
Use this command to find out what directory you are working in.
% pwd
/u/ma/jeremy
% cd homework
% pwd
/u/ma/jeremy/homework
% ls
assign-1 assign-2 assign-3
% cd
% pwd
/u/ma/jeremy
%

Jeremy began by working in his “home” directory. Then he cd ‘d into his homework subdirectory. Cd means ” change directory”. He used pwd to check to make sure he was in the right place, then used ls to see if all his homework files were there. (They were). Then he cd’d back to his home directory.
rm
Use rm to remove files from your directory.
% rm foo
remove foo? y
% rm letter*
remove letter1? y
remove letter2? y
remove letter3? n
%

The first command removed a single file. The second command was intended to remove all files beginning with the string “letter.” However, our user (Jeremy?) decided not to remove letter3.
rmdir
Use this command to remove a directory. For example, to remove a directory called “essays”, do this:

% rmdir essays

A directory must be empty before it can be removed. To empty a directory, use rm.
rsh
Use this command if you want to work on a computer different from the one you are currently working on. One reason to do this is that the remote machine might be faster. For example, the command

% rsh solitude

connects you to the machine solitude. This is one of our public workstations and is fairly fast.

setenv
% echo $PRINTER
labprinter
% setenv PRINTER myprinter
% echo $PRINTER
myprinter
sort
Use this commmand to sort a file. For example, suppose we have a file dict with contents
red rojo
green verde
blue azul
white blanco
black negro

Then we can do this:
% sort dict
black negro
blue azul
green verde
red rojo
white blanco

Here the output of sort went to the screen. To store the output in file we do this:
% sort dict >dict.sorted

You can check the contents of the file dict.sorted using cat , more , or emacs .
tail
Use this command to look at the tail of a file. For example,

% tail essay.001

displays the last 10 lines of the file essay.001 To see a specific number of lines, do this:

% tail -n 20 essay.001

This displays the last 20 lines of the file.
tar
Use create compressed archives of directories and files, and also to extract directories and files from an archive. Example:

% tar -tvzf foo.tar.gz

displays the file names in the compressed archive foo.tar.gz while

% tar -xvzf foo.tar.gz

extracts the files.
telnet
Use this command to log in to another machine from the machine you are currently working on. For example, to log in to the machine “solitude”, do this:

% telnet solitude

See also: rsh.
wc
Use this command to count the number of characters, words, and lines in a file. Suppose, for example, that we have a file dict with contents

red rojo
green verde
blue azul
white blanco
black negro

Then we can do this
% wc dict
5 10 56 tmp

This shows that dict has 5 lines, 10 words, and 56 characters.

The word count command has several options, as illustrated below:

% wc -l dict
5 tmp
% wc -w dict
10 tmp
% wc -c dict
56 tmp
dummy
Under construction

This guide shows how to create a stylish rollover effect for a menu which might normally be done with Javascript or DHTML. CSS is used to do the menu highlighting.

http://www.ssi-developer.net/css/menu-rollover-effect.shtml

New Design View and CSS Design Tools

The Web page designer now lets you work in Design view, Source view, or Split view, which displays Design view and Source view at the same time.

Visual Studio now provides tools that make it easy to work with cascading style sheets (CSS). You can design the layout and style content in Design view by using new UI tools such as the CSS Properties window. You can also change positioning, padding, and margins directly in Design view by using WYSIWYG visual-layout tools.

For more information, see the following topics:

* Working with CSS Overview

* Walkthrough: Creating and Modifying a CSS File

IntelliSense for JScript and ASP.NET AJAX

Visual Studio 2008 and Visual Web Developer Express Edition now offer significantly improved IntelliSense for coding in ECMAScript (JScript or JavaScript), and for writing client script for AJAX-style Web applications that use the Microsoft AJAX Library. IntelliSense is available for client script in script elements and for referenced .js script files.

Additionally, IntelliSense displays XML code comments. XML code comments are used to describe the summary, parameter, and return details of your client script. ASP.NET AJAX also uses XML code comments to provide IntelliSense for ASP.NET AJAX types and members. IntelliSense is also supported for external script file references that use XML code comments.

For more information, see the following topics:

* JScript IntelliSense Overview

* Walkthrough: JScript IntelliSense

Web Application Projects

Web applications projects, released earlier as an add-on for Visual Studio 2005, are now integrated into Visual Studio and By using the Web application project model, you can compile a Web site into a single assembly in the Bin folder and explicitly define project resources.

The Web application project model uses the same project, build, and compilation semantics as Web projects in Visual Studio .NET 2003. This enables you to easily migrate Visual Studio .NET 2003 Web sites to the current version of Visual Studio or Visual Web Developer Express Edition.

Web application projects do not replace the Web site project type introduced in Visual Studio 2005. Instead, they provide another project model to provide more options for how you deploy and maintain Web applications.

For more information, see the following topics:

* Web Application Projects Overview

* How to: Create New Web Application Projects

Multi-targeting Web Applications

Visual Studio now enables you to target a Web application to a specific version of the .NET Framework. You can use one instance of the Visual Studio to develop Web applications for .NET Framework versions 2.0, 3.0 (Windows Vista), and 3.5. In Visual Web Developer Express Edition, you can only create applications that target the 3.5 version of the .NET Framework. However, you can later change the .NET Framework to target versions 2.0, 3.0, and 3.5 by changing the related project property.

For more information, see the following topics:

* .NET Framework Multi-Targeting Overview

* How to: Target a Specific .NET Framework

Designer and IntelliSense Support for LINQ

A new set of features in Visual Studio 2008 support Language-Integrated Query (LINQ) and extend the powerful query capabilities into the language syntax of C# and Visual Basic. LINQ introduces standard, easily-learned patterns for querying and transforming data, and can be extended to support any kind of data source. The designer provides a visual representation of data classes that enables you to quickly create and edit classes that map to objects in a database. IntelliSense support provides information for LINQ language syntax and for using the LinqDataSource control in Source view. For more information, see LinqDataSource Web Server Control Overview
Support for Creating and Consuming WCF Services in a Web Project

In Visual Studio, you can add ASP.NET Web services (.asmx files) and WCF Web services (.svc files) to a project. Client applications that are written in managed code typically access these Web services through a proxy class. For example, these applications use the proxy class that Visual Studio generates when you use the Add Web Reference dialog box. AJAX applications can access Web services from the browser by using proxy classes that are automatically generated in client script. For more information, see ASP.NET Application Services Overview.
Support for ASP.NET AJAX Extender Controls

AJAX extender controls enhance the client capabilities of standard Web server controls in ASP.NET Web applications. You can provide a richer Web-based user experience by binding one or more extenders to Web server controls such as TextBox controls, Button controls, and Panel controls.

Visual Studio supports all ASP.NET AJAX extender controls. This includes extender controls that you create and those that you add from sources such as the ASP.NET AJAX Control Toolkit, which is available on the ASP.NET Web site.

The .NET Framework version 3.5 Service Pack 1 includes enhancements for ASP.NET in targeted areas. Visual Studio 2008 and Microsoft Visual Web Developer Express Edition also include enhancements and new features for improved Web development.

The most significant advances are improved support for developing AJAX-enabled Web sites and support for Language-Integrated Query (LINQ). The advances include new server controls and types, a new object-oriented client type library, and full IntelliSense support in Visual Studio 2008 and Microsoft Visual Web Developer Express Edition for working with ECMAScript (JavaScript or JScript).

The following sections of this topic describe the changes in ASP.NET and Visual Web Developer.

* ASP.NET Enhancements in SP1
* ASP.NET Enhancements in version 3.5
* Visual Web Developer Enhancements

ASP.NET Enhancements in SP1

The following sections provide information about enhancements and new features in Visual Studio 2008 and Visual Web Developer Express Edition.

Dynamic Data

ASP.NET Dynamic Data is a framework that lets you create data-driven ASP.NET Web applications easily. It does this by automatically discovering the data model at run time and determining UI behavior from it. A scaffolding framework instantly provides a functional Web site for viewing and editing data. This scaffolding can then be easily customized using metadata, templates, or by creating standard ASP.NET pages to override the default behavior. At the same time existing applications can easily integrate pieces of the scaffolding logic with their existing pages.
URL Routing

URL routing in ASP.NET enables you to use URLs that do not have to map to specific files in a Web site. Because the URL does not have to map to a file, you can use URLs in a Web application that are descriptive of the user’s action and therefore more easily understood by users. In URL routing, you define URL patterns that contain placeholders for values that are used when you handle URL requests. At run time, the pieces of the URL that follow the application name are parsed into discrete values, based on a URL pattern that you have defined.
EntityDataSource Control

The EntityDataSource control supports data binding scenarios based on the Entity Data Model (EDM). The EDM specification represents data as sets of entities and relationships. The EDM is used by the Entity Framework in object-relational mapping and in other scenarios such as ADO.NET Data Services. Users accustomed to the design-time model of ASP.NET data binding controls will find the programming surface of the EntityDataSource control similar to that of other data source controls.

The EntityDataSource control manages create, read, update, and delete operations with a data source on behalf of data-bound controls on the page. The EntityDataSource works with editable grids, forms with user-controlled sorting and filtering, dually bound drop-down list controls, and master-detail pages. The EntityDataSource control is able to obtain query parameter values from page controls, query parameters appended to the page URI, cookies, and other ASP.NET parameter objects.

New ASP.NET AJAX Extensions

The new extensions for ASP.NET AJAX in SP1 give you more control over browser history when you use the Back button. They also enable multiple client scripts to be automatically combined into one composite script. This speeds script load time by greatly reducing the required number of round trips to the server.

JScript Formatting

Code formatting capabilities has been extended to support JScript in Visual Studio and Visual Web Developer Express Edition. You can choose to format code manually for a document or selection, or to be automatically formatted as you type.
ASP.NET Enhancements in version 3.5

The .NET Framework version 3.5 includes enhancements for ASP.NET in the following areas:

* New server controls, types, and a client-script library that work together to enable you to develop AJAX-style Web applications.

* Extension of server-based forms authentication, roles management, and profile services as Web services that can be consumed by Web-based applications.

*A new EntityDataSource control that exposes the Entity Data Model through the ASP.NET data source control architecture.

*A new ListView data control that displays data and that provides a highly customizable UI.

* A new LinqDataSource control that exposes Language-Integrated Query (LINQ) through the ASP.NET data source control architecture.

* A new merge tool (Aspnet_merge.exe) that merges precompiled assemblies to support flexible deployment and release management. This feature is not available in Visual Web Developer Express Edition.

The .NET Framework version 3.5 is also integrated with IIS 7.0. You can now use ASP.NET services such as forms authentication and caching for all content types, not just ASP.NET Web pages (.aspx files). This is because ASP.NET and IIS 7.0 use the same request pipeline. The unified request processing pipeline means that you can use managed code to develop HTTP pipeline modules that work with all requests in IIS. In addition, IIS and ASP.NET modules and handlers now support unified configuration. For more information, see ASP.NET Application Life Cycle Overview for IIS 7.0.
AJAX Development

The .NET Framework version 3.5 enables you to create Web applications that feature next-generation user interfaces with reusable client components. You can develop Web pages by using a server-based approach, a client-based approach, or a combination of both, according to your requirements. The AJAX server-based and client-based programming models feature the following:

* Server controls that support server-based AJAX development. This includes the ScriptManager, UpdatePanel, UpdateProgress, and Timer controls. These controls enable you to create rich client behavior with little or no client script, such as partial-page rendering and displaying update progress during asynchronous postbacks.

*The Microsoft AJAX Library, which supports client-based, object-oriented development that is browser independent. In addition to supporting the new AJAX-enabled server controls, the client library enables you to develop custom client components that extend DOM elements or that represent a DOM element.

* Server classes that enable you to develop server controls that map to custom client components whose events and properties are set declaratively. Server types that support this functionality include controls that derive from the ExtenderControl or ScriptControl base classes, or that implement the IExtenderControl or IScriptControl interfaces.
* Support for script globalization and localization by using client script. Globalization enables you to display dates and numbers based on a culture value (locale). Localization enables you to specify localized content (text, images, and so on) in client components for UI elements or exception messages.

* Access to Web services and to ASP.NET authentication, roles management, and profile application services.

The .NET Framework version 3.5 enables you to easily enable asynchronous partial-page updates in a page, which avoids the overhead of full-page postbacks. You can just put existing controls and markup inside UpdatePanel controls. Postbacks from inside an UpdatePanel control become asynchronous postbacks and refresh only the part of the page that is inside the panel, which creates a more fluid user experience. You can display the progress of the partial-page update by using UpdateProgress controls.
Learning About AJAX Development in ASP.NET

The documentation provides extensive information to help you learn how to develop AJAX-style Web applications in ASP.NET. To start, follow the sequence of topics described in Adding AJAX and Client Capabilities Roadmap.
Web Services and Application Services

The .NET Framework version 3.5 enables you to create both ASP.NET (.asmx) and WCF-based Web services that you can call from Web pages in client script by using the Microsoft AJAX Library. You can also call server-based application services that are exposed as Web services, which includes forms authentication, roles management, and profiles. These application services can be consumed in WCF-compatible applications, which includes AJAX-enabled Web pages and Window Forms clients. As a result, applications that are built with these ASP.NET or WCF technologies can share information that is made available by application services. For more information, see Web Services in ASP.NET AJAX and Using ASP.NET Web Services.
ListView Data Control

The ListView control combines many aspects of existing data controls. The ListView control is useful for displaying data in any repeating structure, similar to the DataList and Repeater controls. Unlike those controls, the ListView control supports edit, insert, and delete operations as well as sorting and paging. The paging functionality is provided for ListView by the new DataPager control.

The ListView control is a highly customizable control that enables you to use templates and styles to define the control’s UI. Like the Repeater, DataList, and FormView controls, templates in the ListView control are not predefined to render specific UI in the browser. For more information, see ListView Web Server Control Overview.
DataPager Control

The DataPager control is used to page through data that is displayed by a control that implements the IPageableItemContainer interface, such as the ListView control. The DataPager control supports built-in paging UI. You can specify the paging UI by using the NumericPagerField object, which lets users select a page by page number. You can also use the NextPreviousPagerField object, which lets users navigate through pages one page at a time, or to jump to the first or last page. Alternatively, you can create custom paging UI by using the TemplatePagerField object.
LinqDataSource Control

The LinqDataSource control exposes Language Integrated Query (LINQ) through the ASP.NET data source control architecture. You use the LinqDataSource control when you are creating a Web page that retrieves or modifies data and you want to use the programming model that is provided by LINQ. You can simplify the code in a Web page by enabling the LinqDataSource control to automatically create the commands for interacting with the data. By using the LinqDataSource control, you can reduce the amount of code that you must write to perform data operations when compared to performing the same operations in the SqlDataSource control or the ObjectDataSource control. When you use the LinqDataSource control, you also benefit by learning only one programming model to interact with different types of data sources.

You can use declarative markup to create a LinqDataSource control that connects to data from either a database or a data collection such as a collection. In the markup, you can specify the criteria for displaying, filtering, ordering, and grouping data. When the data source is an SQL database table, you can also configure a LinqDataSource control to update, insert, and delete data. You do not have to write the SQL commands to perform these tasks. The LinqDataSource class provides an event model that enables you to customize display and update behavior. For more information, see LinqDataSource Web Server Control Overview.

* Do not open any files attached to an email from an unknown, suspicious or untrustworthy source.

* Do not open any files attached to an email unless you know what it is, even if it appears to come from a dear friend or someone you know. Some viruses can replicate themselves and spread through email. Better be safe than sorry and confirm that they really sent it.

* Do not open any files attached to an email if the subject line is questionable or unexpected. If the need to do so is there always save the file to your hard drive before doing so.

* Delete chain emails and junk email. Do not forward or reply to any to them. These types of email are considered spam, which is unsolicited, intrusive mail that clogs up the network.

* Do not download any files from strangers.

* Exercise caution when downloading files from the Internet. Ensure that the source is a legitimate and reputable one. Verify that an anti-virus program checks the files on the download site. If you’re uncertain, don’t download the file at all or download the file to a floppy and test it with your own anti-virus software.

* Update your anti-virus software regularly. Over 500 viruses are discovered each month, so you’ll want to be protected. These updates should be at the least the products virus signature files. You may also need to update the product’s scanning engine as well.

* Back up your files on a regular basis. If a virus destroys your files, at least you can replace them with your back-up copy. You should store your backup copy in a separate location from your work files, one that is preferably not on your computer.

Antivirus software is a computer program that detects, prevents, and takes action to disarm or remove malicious software programs, such as viruses and worms. You can help protect your computer against viruses by using antivirus software.

Computer viruses are software programs that are deliberately designed to interfere with computer operation, record, corrupt, or delete data, or spread themselves to other computers and throughout the Internet.

To help prevent the most current viruses, you must update your antivirus software regularly. You can set up most types of antivirus software to update automatically.

Here are two types of antivirus protection from Microsoft:

For continuous protection, try Windows Live OneCare, which automatically scans your computer for viruses. You can use it free for 90 days.

For on-demand protection, Windows Live OneCare safety scanner allows you to visit a Web site and scan your computer for viruses and other malicious software for free using Windows Live OneCare safety scanner.

You may be wondering why you should choose PHP over other languages such as Perl or even why you should learn a scripting language at all. I will deal with learning scripting languages first. Learning a scripting language, or even understanding one, can open up huge new possibilities for your website. Although you can download pre-made scripts from sites like Hotscripts, these will often contain advertising for the author or will not do exactly what you want. With an understanding of a scripting language you can easily edit these scripts to do what you want, or even create your own scripts.

Using scripts on your website allows you to add many new ‘interactive’ features like feedback forms, guestbooks, message boards, counters and even more advanced features like portal systems, content management, advertising managers etc. With these sort of things on your website you will find that it gives a more professional image. As well as this, anyone wanting to work in the site development industry will find that it is much easier to get a job if they know a scripting language.

Up until recently, scripting on the internet was something which very few people even attempted, let alone mastered. Recently though, more and more people have been building their own websites and scripting languages have become more important. Because of this, scripting languages are becomming easier to learn and PHP is one of the easiest and most powerful yet.

PHP stands for Hypertext Preprocessor and is a server-side language. This means that the script is run on your web server, not on the user’s browser, so you do not need to worry about compatibility issues. PHP is relatively new (compared to languages such as Perl (CGI) and Java) but is quickly becomming one of the most popular scripting languages on the internet.

Visual Web Developer 2005 Express Edition is part of the Microsoft Visual Studio 2005 family, and is the best development tool for building data driven web applications with ASP.NET 2.0. As part of the Express family, Visual Web Developer provides a seamless upgrade path to Visual Studio Standard, Professional, and Team System.

Visual Web Developer is tuned to the specific needs of the Web developer through a new Web profile that exposes a menu and window layout optimized for Web development. The environment includes a best-of-breed HTML source editor, an improved visual page designer, a new project system, better support for working with data, and full XHTML standards support. Collectively, these features enable you to develop data-driven Web applications faster and easier than ever before. Below we’ll dive in and explore a few of the many Web development improvements coming with Visual Web Developer.

Better Source Code Editing

Visual Web Developer has an improved HTML source editor which enables you to write and modify your pages faster. The source editor provides full Intellisense throughout your files and has new features for navigating and validating your markup.

Intellisense Everywhere
Intellisense — the popup code hints which appear while you type — has a dramatic impact on your productivity as a developer. While support for Intellisense in Visual Studio .NET 2003 is excellent today, support for Intellisense in Visual Web Developer gets even better.

In Visual Web Developer, Intellisense pops up everywhere. For example, you can take full advantage of Intellisense within the script blocks in single file ASP.NET pages. In addition, Visual Web Developer also supports Intellisense for ASP.NET Page Directives and for inline CSS style attributes within a page.
HTML Formatting Options
Visual Web Developer enables you to precisely control the format of all HTML and ASP.NET Server Control markup generated using the WYSIWYG designer. You can now configure the tag casing, attribute quotation, indention style and word wrap characteristics of every html or server control tag in a page. You can set these formatting options as defaults for all markup, as well as optionally override each formatting option on a per tag/control basis. This provides you with the flexibility to fully control exactly how you want your markup to be generated.

HTML format settings can be exported and imported from Visual Web Developer to enable markup style standardization across multiple developers on a team. Visual Web Developer also enables developers to easily apply HTML formatting rules to existing markup source (to handle those cases when you need to update existing HTML source with new formatting rules).

Tag Navigator
The HTML source editor within Visual Web Developer ships with a new �Tag Navigator� feature that enables developers to easily track their location and navigate within a complicated HTML document. The Tag Navigator displays the current “path” within the source of an HTML page by displaying a list of all the HTML tags which contain the tag where your cursor is currently located. Clicking on any of the nodes enables developers to optionally change the source level selection, and quickly move up and down a deep HTML hierarchy.

Imagine, for example, that you are editing the source of an HTML page with multiple nested HTML tables. Editing nested tables can be challenging since it is easy to get lost within the jumble of nested table rows and cells. However, by taking advantage of the Tag Navigator, you can avoid getting lost since the Tag Navigator continuously displays your current path within the hierarchy of table elements.

Tag Outlining
Tag Outlining enables you to work more effectively with large HTML documents. With Tag Outlining, you can right-click any HTML tag in the source editor and select Collapse Tag to hide the entire contents of the tag. Collapsing different regions of the HTML source code contained in a page makes it easier to focus on the particular region of the page which you need to edit.