.Net frame work developed by Microsoft. It primarily run on Microsoft windows. It has large class library called Framework Class Library(FCL). Programs written in the .net framework execute in a software environment called Common Language Runtime (CLR). It provides language interoperability across several programming languages.
It simplifies application development in the highly distributed environment of the Internet. It provides object-oriented programming environment. It minimizes software deployment and guarantees safe execution of code. It eliminates the performance problems. There are different types of application, such as Windows-based applications and desktop-applications, can develop using .net framework.
XML WEB SERVICES Windows Forms
Base Class Libraries
Common Language Runtime
Fig 1. .NET Framewok
Common Language Runtime (CLR):
The CLR is the âexecution engineâ of .NET. It provides the environment within which programs run. The most important features are
â¢ Conversion from a low-level assembler-style language, called Intermediate Language (IL), into code native to the platform being executed on.
â¢ Memory management, notably including garbage collection.
â¢ Checking and enforcing security restrictions on the running code.
â¢ Loading and executing programs, with version control and other such features.
â¢ The following features of the .NET framework are also worth description:
The code that targets .NET, and which contains certain extra Information called âmetadataâ to describe itself. Whilst both managed and unmanaged code can run in the runtime, only managed code contains the information that allows the CLR to guarantee, for instance, safe execution and interoperability.
With Managed Code comes Managed Data. CLR provides memory allocation and Deal location facilities, and garbage collection. Some .NET languages use Managed Data by default, such as C#, Visual Basic.NET and JScript.NET, whereas others, namely C++, do not. Targeting CLR can, depending on the language youâre using impose certain constraints on the features available. As with managed and unmanaged code, one can have both managed and unmanaged data in .NET applications – data that doesnât get garbage collected but instead is looked after by unmanaged code.
Common Type System
The CLR uses something called the Common Type System (CTS) to strictly enforce type-safety. This ensures that all classes are compatible with each other, by describing types in a common way. CTS define how types work within the runtime, which enables types in one language to interoperate with types in another language, including cross-language exception handling. As well as ensuring that types are only used in appropriate ways, the runtime also ensures that code doesnât attempt to access memory that hasnât been allocated to it.
Common Language Specification
The CLR provides built-in support for language interoperability. To ensure that you can develop managed code that can be fully used by developers using any programming language, a set of language features and rules for using them called the Common Language Specification (CLS) has been defined. Components that follow these rules and expose only CLS features are considered CLS-compliant.
Framework Class Library(FCL):
.NET provides a single-rooted hierarchy of classes, containing over 7000 types. The root of the namespace is called System; this contains basic types like Byte, Double, Boolean, and String, as well as Object. All objects derive from System. Object. As well as objects, there are value types. Value types can be allocated on the stack, which can provide useful flexibility. There are also efficient means of converting value types to object types if and when necessary.
The set of classes is pretty comprehensive, providing collections, file, screen, and network I/O, threading, and so on, as well as XML and database connectivity.
The class library is subdivided into a number of sets (or namespaces), each providing distinct areas of functionality, with dependencies between the namespaces kept to a minimum.
Languages supported by .Net:
Following are the some of the languages which support .Net framework:
Visual Basic .NET is also CLS compliant, which means that any CLS-compliant language can use the classes, objects, and components you create in Visual Basic .NET.
Managed Extensions for C++ and attributed programming are just some of the enhancements made to the C++ language. Managed Extensions simplify the task of migrating existing C++ applications to the new .NET Framework.
C# is Microsoftâs new language. Itâs a C-style language that is essentially âC++ for Rapid Application Developmentâ. Unlike other languages, its specification is just the grammar of the language. It has no standard library of its own, and instead has been designed with the intention of using the .NET libraries as its own.
Microsoft Visual J# .NET provides the easiest transition for Java-language developers into the world of XML Web Services and dramatically improves the interoperability of Java-language programs with existing software written in a variety of other programming languages.
Active State has created Visual Perl and Visual Python, which enable .NET-aware applications to be built in either Perl or Python. Both products can be integrated into the Visual Studio .NET environment. Visual Perl includes support for Active Stateâs Perl Dev Kit.
C#.NET is a CLS-compliant language. Any objects, classes, or components that created in C#.NET can be used in any other CLS-compliant language. In addition, we can use objects, classes, and components created in other CLS-compliant languages in C#.NET .The use of CLS ensures complete interoperability among applications, regardless of the languages used to create the application.
The OLAP Services feature available in SQL Server version 7.0 is now called SQL Server 2000 Analysis Services. The term OLAP Services has been replaced with the term Analysis Services. Analysis Services also includes a new data mining component. The Repository component available in SQL Server version 7.0 is now called Microsoft SQL Server 2000 Meta Data Services. References to the component now use the term Meta Data Services. The term repository is used only in reference to the repository engine within Meta Data Services
SQL-SERVER database consist of six type of objects,
A database is a collection of data about a specific topic.
VIEWS OF TABLE
We can work with a table in two types,
1. Design View
2. Datasheet View
To build or modify the structure of a table we work in the table design view. We can specify what kind of data will be hold.
To add, edit or analyses the data itself we work in tables datasheet view mode.
A query is a question that has to be asked the data. Access gathers data that answers the question from one or more table. The data that make up the answer is either dynaset (if you edit it) or a snapshot (it cannot be edited). Each time we run query, we get latest information in the dynaset. Access either displays the dynaset or snapshot for us to view or perform an action on it, such as deleting or updating.