ADO.NET Objects

The SqlConnection Object
The SqlCommand Object
The SqlDataReader Object
The Dataset Object
The SqlDataAdapter Object

Data provider

We know that ADO.NET allows us to interact with different types of data sources and different types of databases. However, there isn't a single set of classes that allow you to accomplish this universally. Since different data sources expose different protocols, we need a way to communicate with the right data source using the right protocol. Some older data sources use the ODBC protocol, many newer data sources use the OleDb protocol, and there are more data sources every day that allow you to communicate with them directly through .NET ADO.NET class libraries.
ADO.NET provides a relatively common way to interact with data sources, but comes in different sets of libraries for each way you can talk to a data source. These libraries are called Data Providers and are usually named for the protocol or data source type they allow you to interact with.

Data Provider is a set of components including:

The Connection object (SqlConnection, OleDbConnection, OdbcConnection,OracleConnection)
The Command object (SqlCommand, OleDbCommand, OdbcCommand, OracleCommand)
The DataReader object (SqlDataReader, OleDbDataReader, OdbcDataReader,OracleDataReader)
And the DataAdapter object (SqlDataAdapter, OleDbDataAdapter, OdbcDataAdapter,OracleDataAdapter).

.NET Framework data providers

Data Provider for SQL Server (System.Data.SqlClient).
Data Provider for OLEDB (System.Data.OleDb).
Data Provider for ODBC (System.Data.Odbc). 

Data Provider for Oracle (System.Data.OracleClient).

Evolution of ADO.NET

The first data access model, DAO (data access model) was created for local databases with the built-in Jet engine which had performance and functionality issues. Next came RDO (Remote Data Object) and ADO (Active Data Object) which were designed for Client Server architectures but, soon ADO took over RDO. ADO was a good architecture but as the language changes so is the technology

Understanding ADO.NET

In organizations, business applications need to the data. Data is stored in a relational database in the form of related tables.
Retrieving and manipulating data directly from a database requires the knowledge of database commands. this may at times become a limitation because everyone may not be conversant with database commands. for example, updating the data stored in a SQl server database may not be convenient for a person who does not know DML (Data manipulation language) commands or statements 

To overcome this limitation ,business application allow users to retrieve data stored in a database and present it in a user-friendly interface, without having to write database commands. the user can even add, delete and update database records directly from these applications.

Why ADO.NET?

Likewise, if a database is Updated, the connection is opened long enough to complete the Update operation and is closed. By keeping connections open for only a minimum period of time, ADO .NET conserves system resources and provides maximum security for databases and also has less impact on system performance.
Also, ADO .NET when interacting with the database uses XML and converts all the data into XML format for database related operations making them more efficient.
napplication interacts with the database, the connection is opened to serve the request of the application and is closed as soon as the request is completed.

What is ADO.NET

ADO.NET is the new database technology of the .NET (Dot Net) platform, and it builds on Microsoft ActiveX� Data Objects (ADO).
ADO is a language-neutral object model that is the keystone of Microsoft's Universal Data Access strategy. ADO.NET is an integral part of the .NET Compact Framework, providing access to relational data, XML documents, and application data. ADO.NET supports a variety of development needs. You can create database-client applications and middle-tier business objects used by applications, tools, languages or Internet browsers
ADO.NET is a set of computer software components that programmers can use to access data and data services. It is a part of the base class library that is included with the Microsoft .NET Framework
It is commonly used by programmers to access and modify data stored in relational database systems, though it can also access data in non-relational sources.
 ADO.NET is sometimes considered an evolution of ActiveX Data Objects (ADO) technology, but was changed so extensively that it can be considered an entirely new product.

ADO.NET comming soon..................

What are the benefits of .NET?

.NET provides the best platform available today for delivering Windows software. .NET helps make software better, faster, cheaper, and more secure. .NET is not the only solution for developing Web software—Java on Linux is a serious alternative. But on the Windows desktop, .NET rules.

For developers, .NET provides an integrated set of tools for building Web software and services and Windows desktop applications. .NET supports multiple programming languages and Service Oriented Architectures (SOA).

For companies, .NET provides a stable, scalable and secure environment for software development. .NET can lower costs by speeding development and connecting systems, increase sales by giving employees access to the tools and information they need, and connect your business to customers, suppliers and partners.

For end-users, .NET results in software that’s more reliable and secure and works on multiple devices incl

What is the history of .NET?

.NET started as a classic Microsoft FUD operation. In the late 1990s, Microsoft had just successfully fought off a frontal assault on its market dominance by killing the Netscape Web browser with its free Internet Explorer. But Microsoft was facing a host of new challenges, including serious problems with COM, C++, DLL hell, the Web as a platform, security, and strong competition from Java, which was emerging as the go-to language for Web development.

Microsoft started building .NET in the late 90s under the name “Next Generation Windows Services” (NGWS). Bill Gates described .NET as Microsoft’s answer to the “Phase 3 Internet environment, where the Internet becomes a platform in its own right, much like the PC has traditionally been… Instead of a world where Internet users are limited to reading information, largely one screen at a time, the Phase 3 Internet will unite multiple Web sites running on any device, and allow users to read, write and annotate them via speech, handwriting recognition and the like,” Gates said. We are certainly approaching that vision.

Microsoft announced .NET to the world in June 2000 and released version 1.0 of the .NET framework in January 2002. Microsoft also labeledeverything .NET including briefly Office to demonstrate its commitment and dominance on this new thing called the Web. But out of that grand FUD campaign emerged the very capable and useful .NET development environment and framework for both the Web and Windows desktop.

.Net Namespaces

The .NET Framework Class Library (FCL ) is a large collection of thousands of Classes. These Classes are organized in a hierarchical tree. The System Namespaces is the root for types in the .NET Framework. We can uniquely identify any Class in the .NET Framework Class Library (FCL ) by using the full Namespaces of the class .In .Net languages every program is created with a default Namespaces . Programmers can also create their own Namespaces in .Net languages.

Common Language Runtime (CLR)

The CLR is the execution engine for .NET applications and serves as the interface between .NET applications and the operating system. The CLR provides many services such as:

·      1.   Loads and executes code

·       2.  Converts intermediate language to native machine code

·      3.   Separates processes and memory

·      4.   Manages memory and objects

·     5.    Enforces code and access security

·     6.    Handles exceptions

·      7.   Interfaces between managed code, COM objects, and DLLs

·     8.    Provides type-checking

·     9.    Provides code meta data (Reflection)

10.Provides profiling, debugging, etc

Common Language Specification (CLS)

The CLS is a common platform that integrates code and components from multiple .NET programming languages. In other words, a .NET application can be written in multiple programming languages with no extra work by the developer (though converting code between languages can be tricky).

.NET includes new object-oriented programming languages such as C#,Visual Basic .NET, J# (a Java clone) and Managed C++. These languages, plus other experimental languages like F#, all compile to the Common Language Specification and can work together in the same application.

Why not Java?

This article is not a tirade or attack on Java. In general, this article is targeted at Win32 developers and not Java developers. But the question still arises, �Why .NET instead of Java?�. I will only summarize my view on this in this article. In another future article, I shall compare .NET and Java and prognosticate on the future.

Java is an established platform with its own merits. This article merely states my reasons why I think .NET is important. I have only referenced the Java platform when a contrast or specific difference existed that I felt was of particular importance.

.NET is superior to Java as a platform in many areas, while Java is superior in others. The key difference though is that .NET will close the gap in the future with little need for change, while Java cannot close the gaps without a major redesign into something quite different than it is now.

Some advantages that .NET has over Java are:

1. Java is not just a platform, but a language. .NET is language independent. Adopting .NET does not force you to adopt a single, or even specific language. .NET can even support the Java language, and J# is very close to Java.
2. Language interoperability.
3. .NET can coexist with and even integrate with existing Win32 code.
4. Moving to Java from Win32 is a complete paradigm shift. Moving to .NET is a more natural path for Win32 developers.

Why .NET is coming...?

.NET is the future of development not only for the Windows platform, but other operating systems as well. If you are not moving to .NET now, you should at least be keeping up to date with it and reevaluating it at regular intervals to determine when you will begin moving to it.

.NET is coming. Ignoring this fact will not slow it, or stop it. Those that do not move to it will be dinosaurs. It's better to plan for a migration than to become extinct.

If you begin evaluating .NET now and plan for a smooth and timely migration, you will reap the benefits. However, if you wait too long, the future is quite predictable, and can easily be seen by looking at the DOS developer that we all know who refuses to admit Windows has arrived.

Metadata Overview

Metadata is binary information describing your program that is stored either in a common language runtime portable executable (PE) file or in memory. When you compile your code into a PE file, metadata is inserted into one portion of the file, while your code is converted to Microsoft intermediate language (MSIL) and inserted into another portion of the file. Every type and member defined and referenced in a module or assembly is described within metadata. When code is executed, the runtime loads metadata into memory and references it to discover information about your code's classes, members, inheritance, and so on. nMetadata describes every type and member defined in your code in a language-neutral manner. Metadata stores the following information:
Description of the assembly.
Identity (name, version, culture, public key).
The types that are exported.
Other assemblies that this assembly depends on.
Security permissions needed to run.
Description of types.
Name, visibility, base class, and interfaces implemented.
Members (methods, fields, properties, events, nested types).
Attributes.
Additional descriptive elements that modify types and members.

Garbage Collection

The .Net Framework provides a new mechanism for releasing unreferenced objects from the memory (that is we no longer needed that objects in the program) ,this process is called Garbage Collection (GC). When a program creates an Object, the Object takes up the memory. Later when the program has no more references to that Object, the Object's memory becomes unreachable, but it is not immediately freed. The Garbage Collection checks to see if there are any Objects in the heap that are no longer being used by the application. If such Objects exist, then the memory used by these Objects can be reclaimed. So these unreferenced Objects should be removed from memory , then the other new Objects you create can find a place in the Heap.

source

http://vb.net-informations.com
http://msdn.microsoft.c
 http://www.codeproject.co
http://www.exforsys.com
http://learnenglish.yuku.com

Just In Time Compiler

nThe .Net languages , which is conforms to the Common Language Specification (CLS), uses its corresponding runtime to run the application on different Operating Systems . During the code execution time, the Managed Code compiled only when it is needed, that is it converts the appropriate instructions to the native code for execution just before when each function is called. This process is called Just In Time (JIT) compilation, also known as Dynamic Translation . With the help of Just In Time Compiler (JIT) the Common Language Runtime (CLR) doing these tasks.
nThe Common Language Runtime (CLR) provides various Just In Time compilers (JIT) and each works on a different architecture depending on Operating System. That is why the same Microsoft Intermediate Language (MSIL) can be executed on different Operating Systems without rewrite the source code. Just In Time (JIT) compilation preserves memory and save time during application initialization. Just In Time (JIT) compilation is used to run at high speed, after an initial phase of slow interpretation. Just In Time Compiler (JIT) code generally offers far better performance than interpreters.

Portable Executable (PE) File Format

The Portable Executable (PE) format is a file format for executables, object code, and DLLs, used in 32-bit and 64-bit versions of Windows operating systems.
The PE file format was defined to provide the best way for the Windows Operating System to execute code and also to store the essential data which is needed to run a program. Portable Executable File Format is derived from the Microsoft Common Object File Format (COFF).

Microsoft Intermediate Language

MSIL stands for Microsoft Intermediate Language. We can call it as Intermediate Language (IL) or Common Intermediate Language (CIL). During the compile time , the compiler convert the source code into Microsoft Intermediate Language (MSIL) .Microsoft Intermediate Language (MSIL) is a CPU-independent set of instructions that can be efficiently converted to the native code. During the runtime the Common Language Runtime (CLR)‘ s Just In Time (JIT) compiler converts the Microsoft Intermediate Language (MSIL) code into native code to the Operating System.
When a compiler produces Microsoft Intermediate Language (MSIL), it also produces Metadata. The Microsoft Intermediate Language (MSIL) and Metadata are contained in a portable executable (PE) file . Microsoft Intermediate Language (MSIL) includes instructions for loading, storing, initializing, and calling methods on objects, as well as instructions for arithmetic and logical operations, control flow, direct memory access, exception handling, and other operations

Common Type System

Common Type System (CTS) describes a set of types that can be used in different .Net languages in common . That is , the Common Type System (CTS) ensure that objects written in different .Net languages can interact with each other. For Communicating between programs written in any .NET complaint language, the types have to be compatible on the basic level .
These types can be Value Types or Reference Types .
The Value Types are passed by values and stored in the stack.
The Reference Types are passed by references and stored in the heap. Common Type System (CTS) provides base set of Data Types which is responsible for cross language integration. The Common Language Runtime (CLR) can load and execute the source code written in any .Net language, only if the type is described in the Common Type System (CTS) .Most of the members defined by types in the .NET Framework Class Library (FCL) are Common Language Specification (CLS) compliant Types.

Common Language Specification

MSIL stands for Microsoft Intermediate Language. We can call it as Intermediate Language (IL) or Common Intermediate Language (CIL). During the compile time , the compiler convert the source code into Microsoft Intermediate Language (MSIL) .Microsoft Intermediate Language (MSIL) is a CPU-independent set of instructions that can be efficiently converted to the native code. During the runtime the Common Language Runtime (CLR)'s Just In Time (JIT) compiler converts the Microsoft Intermediate Language (MSIL) code into native code to the Operating System.
When a compiler produces Microsoft Intermediate Language (MSIL), it also produces Metadata. The Microsoft Intermediate Language (MSIL) and Metadata are contained in a portable executable (PE) file . Microsoft Intermediate Language (MSIL) includes instructions for loading, storing, initializing, and calling methods on objects, as well as instructions for arithmetic and logical operations, control flow, direct memory access, exception handling, and other operation

.Net Framework Class Library (FCL)

The .Net framework class library (FCL) provides the core functionality of .Net Framework architecture . The .Net Framework Class Library (FCL) includes a huge collection of reusable classes , interfaces, and value types that expedite and optimize the development process and provide access to system functionality.
The .Net Framework class library (FCL) organized in a hierarchical tree structure and it is divided into Namespaces. Namespaces is a logical grouping of types for the purpose of identification. framework class library (FCL) provides the consistent base types that are used across all .NET enabled languages. The Classes are accessed by namespaces, which reside within Assemblies. The System Namespace is the root for types in the .NET Framework. The .Net Framework class library (FCL) classes are managed classes that provide access to System Services . The .Net Framework class library (FCL) classes are object oriented and easy to use in program developments. Moreover, third-party components can integrate with the classes in the .NET Framework.

How to Microsoft .Net Framework

During the runtime the Common Language Runtime (CLR)'s Just In Time (JIT) compiler converts the Microsoft Intermediate Language (MSIL) code into native code to the Operating System.
The native code is Operating System independent and this code is known as Managed Code , that is, the language's functionality is managed by the .NET Framework .
The Common Language Runtime (CLR) provides various Just In Time (JIT) compilers, and each works on a different architecture depends on Operating Systems, that means the same Microsoft Intermediate Language (MSIL) can be executed on different Operating Systems.
nIn the following section you can see how Common Language Runtime (CLR) functions .

How to Microsoft .Net Framework

Microsoft .Net Languages source code are compiled into Microsoft Intermediate Language (MSIL) . MSIL we can call it as Intermediate Language (IL) or Common Intermediate Language (CIL).
 Microsoft Intermediate Language (MSIL) is a CPU independent set of instructions that can be converted to the native code. Metadata also created in the course of compile time with Microsoft Intermediate Language (MSIL) and stored it with the compiled code .
ematodes is completely self-describing . Metadata is stored in a file called Manifest, and it contains information about the members, types, references and all the other data that the Common Language Runtime (CLR) needs for execution .
the Common Language Runtime (CLR) uses metadata to locate and load classes, generate native code, provide security, and execute Managed Code.
both Microsoft Intermediate Language (MSIL) and Metadata assembled together is known as Portable Executable (PE) file. Portable Executable (PE) is supposed to be portable across all 32-bit operating systems by Microsoft .Net Framework.

What is Microsoft .Net Framework

The Microsoft .Net Framework is a platform that provides tools and technologies you need to build Networked Applications as well as Distribute web services and Web Applications.
The .Net Framework provides the necessary compile time and run-time foundation to build and run any language that conforms to the Common Language Specification (CLS). The main two components of .Net Framework are Common Language Runtime (CLR) and .Net Framework Class Library (FCL)

.NET architecture