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Showing posts from August, 2019

Verifying Use Cases, Data Flow Diagrams, Entity Relationship Diagrams, and State Diagrams via State Linkages.

Verifying Use Cases, Data Flow Diagrams, Entity Relationship Diagrams, and State Diagrams via State Linkages The purpose of this brief article is to provide a simple example on how to link and verify four models: use case, data flow diagrams, entity relationship diagrams, and state diagrams. Note the word verify, not validate. Verify in this context means that the technique is consistent and complete, not that it reflects correct requirements. In writing this article, the author assumes the reader understands the four models mentioned above. With this understanding, the article focuses on the relationship between the models via states. Use case is an alternative technique for documenting functional requirements for interactive operational systems. It models a dialogue (a process) between a user (actor) and a user goal (use case). The technique consists of a diagram and a description. The description of a use case includes pre and post conditions. The precondition is the st

Difference Between Waterfall and Agile Model.

Waterfall methodology is a software development methodology that is based on sequential-linear approach of software development. It reinforces the notion of "define before design" and "design before code". Whereas agile is based on increamental-iterative approach where requirements are expected to change frequently. # Waterfall Agile 1. Waterfall methodology is sequential and linear. Agile methodology is increamental and iterative. 2. Requirements have to be freezed at the beginning of SDLC. Requirements are expected to change and changes are incorporated at any point. 3. Working model of software is delivered at the later phases of SDLC. Working model is delivered during initial phases and successive iteration of the model are delivered to the client for feedback. 4. It is difficult to scale-up projects based on waterfall methodology. Scaling up of products is easy because of the iterative approach. 5. Customers or end user doesn't have a

What is Database? What is SQL?

What is Data? In simple words data can be facts related to any object in consideration. For example your name, age, height, weight, etc are some data related to you. A picture , image , file , pdf etc can also be considered data. What is a Database? Database is a systematic collection of data. Databases support storage and  manipulation of data. Databases make data management easy. Let's discuss few examples. An online telephone directory would definitely use database to store data pertaining to people, phone numbers, other contact details, etc. Your electricity service provider is obviously using a database to manage billing , client related issues, to handle fault data, etc. Let's also consider the facebook. It needs to store, manipulate and present data related to members, their friends, member activities, messages, advertisements and lot more. We can provide countless number of examples for usage of databases . What is a Database Management System (

GCD and LCM easy calculation.

C Program to Find LCM of two Numbers Examples on different ways to calculate the LCM (Lowest Common Multiple) of two integers using loops and decision making statements. To understand this example, you should have the knowledge of following  C programming topics: C Programming Operators C if...else Statement C Programming while and do...while Loop The LCM of two integers  n1  and  n2  is the smallest positive integer that is perfectly divisible by both  n1  and  n2  (without a remainder). For example: the LCM of 72 and 120 is 360. Example #1: LCM using while Loop and if Statement #include <stdio.h> int main () { int n1 , n2 , minMultiple ; printf ( "Enter two positive integers: " ); scanf ( "%d %d" , & n1 , & n2 ); // maximum number between n1 and n2 is stored in minMultiple minMultiple = ( n1 > n2 ) ? n1 : n2 ; // Always true while ( 1 ) { if ( minMul