Information Technology

Aggregate Functions These functions perform an operation on a set of fields and return a single value. Their use is relatively limited. They can be used in the following situations: The selection list of the SELECT statement A HAVING clause A COMPUTE clause Function                                                                                     Description AVG ([ALL| DISTINCT] expression) Returns the average value in the group. COUNT( [ALL|DISTINCT] expression) Counts the number of items in the group. COUNT_BIG( [ ALL|DISTINCT] expression) Counts the number of items in the group. the result is returned in the form of bigint number. GROUPING(Column_Name) Creates an additional column with a value of 1 operator or 0 if it is not the result of a CUBE or ROLLUP operator. MAX( expression) Returns the maximum value in the expression. MIN( expression) Returns the minimum value in the expression. SUM ( expression) returns the sum of the expression's value. STDE

Object oriented system development consists of Object Oriented Analysis Object Oriented Information Modeling Object Oriented Design Prototyping and Implementation Testing, Iteration and Documentation  Five major elements of Object Model: Abstraction Encapsulation Modularity Hierarchy Inheritance Image Courtesy Codeproject Abstraction Abstraction is one of the fundamental elements of object model. Three types of abstraction are- Entity Abstraction, Virtual machine abstraction, Coincidental abstraction. Encapsulation Encapsulation is the process of compartmentalization the elements of an abstraction that constitutes its structure and behavior and serves to separate the contractual interface of abstraction and its implementation. Modularity Modularization consists of dividing a program into modules which can be compiled separately , but which have connection with other modules. The connections between modules are the assumption which the modu

Among the most important information contained in a feasibility study is cost-benefit analysis- an assessment of economic justification for a computer based system project. Introduction Statement of the Problem Implementation Environment Constraints Management Summary and Recommendations  Important Findings Comments Recommendations Impact Alternatives Alternative System Configurations Criteria used in selecting the final approach System Description Abbreviated statement of scope Feasibility of allocated elements Cost Benefit Analysis Evaluation of Technical Risk Legal Ramification Other Project Specific Topics

Procurement Costs Consulting costs Actual equipment purchase or lease costs Equipment installation costs Costs for modifying the equipment site ( air conditioning , security etc) Cost of Capital Cost of Management  and staff dealing with procurement Start up Costs Cost of operating system software Cost of communication equipment installation ( telephone lines, data lines etc) Cost of start up personnel Cost of personnel searches and hiring activities Cost of disruption to the rest of organization Cost of management required to direct start up activity  Project Related Costs Cost of application software purchased Cost of software modifications to fit local systems Cost of personnel, overhead etc from in house application development Cost for training user personnel in application use Cost of data collection and installation data collection procedures Cost of preparing documentation Cost of development management On going Costs System maintenance

Types of Security Threats In general, network security threats can be classified into one of two categories: disruption,destruction and disaster and unauthorized access. disruptions are usually minor and temporary. Some disruptions may also be caused by or result in the destruction of data. Natural or man made disasters may occur that destroy host computers or large sections of the network. Unauthorized access refers to intruders (external hackers or organizational employees) gaining unauthorized access to files. The intruder may gain knowledge, change files to commit fraud or theft or destroy information to injure the organization.  Risk Assessment Developing a secure network means developing controls that reduce or eliminate threats to the network. Controls prevent, detect  and correct whatever might happen to the organization when its computer based systems are threatened. The first step in developing a secure network is to conduct a risk assessment. This is done by com

Using  regular expressions  is probably the best way. Here's an example ( live demo ): function validateEmail ( email ) { var re = /^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/ i ; return re . test ( email ); } But keep in mind that one should not rely only upon JavaScript validation. JavaScript can easily be disabled. This should be validated on the server side as well.