what is web service?

web service is a web-based application without user interface, it has two sides: client and server sides that could be programmed in differrent programming languages, be running in the different operating systems and be exchanging SOAP (simple object access protocal) messages based on  XML documents through HTTP.

what is duplex service?

A duplex service maintains a callback channel to the Silverlight client, which allows the service to make calls to the client at any given time. Duplex services have numerous applications including, for example, a chat server for instant messaging or a monitoring service that sends notifications to the client.

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what is module?

Module is a container for types within an individual assembly.

what is Code Access Security?

CAS is a security system that allows administrators and developers to control application authorization similar to the way that they have always beend able to authorize users. The following resources can be controled by authorization:

• file system
• registry
• printers
• event logs

what is trigger?

A trigger is a special kind of stored procedure that responds to specific events. It is a piece of code attached to a particular table. Unlike sproc, the code in the trigger is automatically run whenever the event(s) that you attached the trigger to occur in the table, without explicitly invoking. The events that a trigger can be attached to are:

• insert
• delete
• update
• a mix and match of any of above.

Triggers can be nested.

Triggers can be recursive.

Triggers can be turned off.

what is a sproc?

Stored procedure is just something like a script or batch that is stored in in the database rather than in a separate file. sproc can have input/output parameters and return values.

why use sproc:

1. call it
2. security
3. erpformance

How to:

• create/drop a sproc
• declare parameters
• flow control (if…else)
• case
• return values
• loop with WHILE
• waitfor
• dealing with errors

what is boxing/unboxing?

boxing: converts a value type to a rference type;

int  i = 123;
object o = (object)i;

unboxing: converts a reference type to a value type;

object o = 123;
int  i = (int)o