Constraints are proactive, meaning they react before modifications are made to the database. This is more efficient because no logging takes place, whereas triggers are reactive. They are invoked after changes are made to the database. Triggers can cascade changes where as constraints cannot. You can write Transact-SQL statements for other actions to take places.

Constraints are proactive, meaning they react before modifications are made to the database. This is more efficient because no logging takes place, whereas triggers are reactive. They are invoked after changes are made to the database. Triggers can cascade changes where as constraints cannot. You can write Transact-SQL statements for other actions to take places.

The most important component of the .net framework is the CLR or the Common Language Runtime. The CLR manages and executes code written in .net languages. It activates objects, performs security checks, lays them out in memory, executes them and garbage collects these objects as well.The CLR is a runtime engine that loads required classes, performs just in time compilations, enforces security checks and a bunch of other runtime functions.The CLR executables are either exe or dll files that consist mostly of metadata and code. These executables must adher to a file format called the Portable Executable (PE) file format

CTS is an acronym for Common Type System which is an integral part of .net and which ensures language compatibility, interoperability and integration. Because .net treats all languages equal a class written in C# should be equivalent to class written in VB.net. Languages must agree on the meaning of these concepts before they can integrate with one another. To make this integration possible Microsoft has specified a common type system which every .net language must follow. There are two types in CTS: value type and reference type. Value types reference values on the stack. When a value type is passed to a function they are passed by value i.e. original value of the passed variable will not change. If a type consumes memory then it should be declared as a reference type. They contain references to heap based objects and are reclaimed by the garbage collector. When you pass a variable by reference then if the called function modifies it, it is visible in the calling function because it works on the actual object contrast to value type where a copy of the object is passed.

Both HTTP GET and HTTP POST use HTTP (Hyper Text Transfer Protocol) as the underlying protocol. The GET and POST methods have been widely in Servlets, CGI, ASP, and many more. Both of these methods encode the request parameters as name value pairs in the HTTP request. The GET method creates a query string and appends it to the script's URL on the server that handles the request. For the POST method the values are passed in the body of the HTTP request message.

Web services allow access to software through standard web protocols such as HTTP and SMTP. They enable software to interact with a wider range of clients. Web services can be consumed by any application that understands how to parse an XML. XML is the key technology used in web services.Microsoft .net web services support three protocols HTTP GET, HTTP POST and SOAP (Simple Object Access Protocol).For the clients to interact with the web services there must be a description of the method calls or interface that the web service supports. This web service description document is found in the XML schema called as WSDL (Web services description language).