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Name: Week: Topic: System development environment and the sources of software Systems development environment and the sources of software System environment is something external to a system that interacts with the system. In computer program or system, the development environment is the set of processes and programming tools used to create the program or software product to form software as a package to solve a programming problem. There are various IDE (Integrated Development Environment) for a different-different programming language, sometimes same environment can be used for multiple programming languages. For example ‘ Microsoft's Visual Studio ’ in a system developm ent environment come up with its own server, database, editor and support multiple languages. There is another popular IDE is ‘ eclipse ’ we can use this multiple programming and web development languages like C, C++, Java, HTML, JSP etc. By using system development environment we can get more source of software at the same place whatever we need it to start working for a small to big project. Again in the world of information technology, we can get software either at very low or zero price. There are millions of freeware they have provided free access to download. Now, almost all the software that can be used to develop software are open-source, that means can be downloaded with zero cost. One of the ways of reducing the cost of software is to make use of the software that is free' or in the public domain'. The common feeling about such kind of software is that it may be full of bugs, viruses and has little or no user support. But that is fine, if there is no user support you might have been a large community support for the same from where one get the solution and proceed with the same. Conceptual Data Modeling: A conceptual data model identifies the top most level of relationships among the different entities. The conceptual data model includes the importance of entities and the relationships among them. Conceptual modeling also looks at how the data is being structured and what are the characteristics of the data area. E-R diagram is one of the ways of representing the relationship between the entity and how they are interconnected with each other. An entity may be defined as a thing capable of an independent existence that can be uniquely identified. Here are the characteristics of the data that can get from E-R Diagram: It shows the relationship among Entity. (One to many, many to one, may to many, one to one) It shows Primary Key Attribute (A property of entity through which an entity can be uniquely identified called Primary Key) Coupling among Entity (Is it tight coupling or loose coupling). Its shows the other attributes too. For example: Movie is an Entity, this can be mapped to a database table like below Movie Table Attribute Primary Key (PK) Description MovieID Yes Movie ID Title Name of Movie Catalog Action or Horror RunningLength 2.5 Hours Director Name of director Rating 4 out of 5 YearOfReleased 2016 So every entity must have attributes to help make it unique that is what called Primary Key. By using above example Person Entity watch Movie entity and rate this. The rating of this movie can vary it totally depends on how the Person Entity feel after watching this movie was it into his/her interest zone or not? Here are three examples and their cardinality: For example, a person entity inserts a credit card into an ATM entity; the ATM entity responds with an action. The person will react differently depending on what the ATM does (reject or accept the credit card). In the context of DBMS, cardinality refers to the number of unique data values contained in a column. If MOVIE Entity is watched by 1000 person that means cardinality is 1000 here. 100 Student entity fills forms to University entity and gets shortlisted for admission on the basis of marks Score entity. If the form is filled with 100 unique students then cardinality is 100. Student entity withdraws Book entity from Library entity. If this process is made by 20 students then cardinality is 20. In entity relationship diagram cardinality can be express in from about 0,1, * (either 0 or 1) and M (many). References : Introduction to Database Management – 14 Aug 2008 by Paulraj Ponniah, Alex Kriegel, Boris M. Trukhov, Allen G.Taylor, Gavin Powell Mark L. Gillenson (Author) Database Management Systems – 20 Dec 2006 by Ramon Mata-Toledo (Author), Pauline Cushman (Author), Debabrata Sahoo (Author)
