Chens Landmark Modelling Technique - Admission/Application Essay Example

? Short IT Paper Executive Summary The world of the 21st century is moving at a fast pace. The fast pace of advancement of the modern day world is more on the lines of rapid change and tremendous development. It is of high importance to mention that the evolution of the telecommunication technology along with the process of evolution of high speed internet and various kinds of technology enabled gadgets has resulted in the process of transforming the world into a well connected single entity. Because of this technology powered transformation of the world around us, a lot of data is being generated in multiple formats. The management and compilation of the data in the variable formats needs to be done by using relational models. The entity relationship models include various vital functionalities which help in the process of manipulation, capturing and sharing of essential data. It has to be said that the usage of relational models in various industries has resulted in the process of increasing the overall efficiency of the industry. Talking in a very specific manner, the examples of the airline industry as well as the banking industry needs to be cited. In the airline industry, a lot of data is automatically generated as a result of real time operations. For the purpose of increasing the efficiency of the various departments in the aviation sector, who needs to have selected and controlled access to various kinds of data, the relational models play a very important role Also, in the banking sector, the relational model concept helps in developing a high level of compatibility in the various departments of the organization, through the process of sharing, viewing and manipulation of highly confidential data of individuals as well as large organizations. Chen’s Landmark modelling technique The logical view of data has gained tremendous importance over the years. There are three very important data models which are network model, relational model as well as the entity set model. All the three models comprises of varying degree of pros and cons. The Chen’s landmark modelling technique is focussed on the entity relationship model, which is being built by combining the advantage of three models. In discussing and explaining the entity relationship model, it can be stated that the model comprises of four levels of data views. The first one is the information concerning entities and relationships that exists in the human minds. In explaining about this particular data view, it can be said that the focus is largely on entities and relationship. Basically an entity is a thing which can be specifically identified while relationship is commonly represented as an association of entities. Normally, the information of entities and relationships are present in the level 1 of the entire logical view. The second one is the information structure which focuses on the organization of information in which the entity and relationships are represented by the data. This is the Level 2 of the entire logical view and the focus is largely on considering the relationships of conceptual objects like entities, values and relationships. The third one is the access path independent data structure which is mainly the data structures which are not involved with regards to search schemes and other indexing schemes. The fourth one is the access path dependent data structure (Chen, 1977, p. 1-14). Modelling Techniques by OMG’s UML The Unified Modelling Language (UML) of Object Management Group (OMG) is the commonly and widely used specification, which is responsible for providing the models of not only application structure, but also behaviour, architecture, business process and data structure (Object Management Group -1, 2013). In discussing about the Object Management Group’s Unified Modelling Language, it can be said that it helps in the process of specifying, visualizing and documenting the models of various software systems. While doing so, the focus is given on the fact that it fulfils all the requirements related to structure and design. The OMG’s UML based tools helps in the process of analyzing the requirements of future applications and design solutions which will help in attaining them. The power of OMG UML is that it helps in the modelling of any kind of application, which is running on a variable combination of hardware, programming language, operating system and network (Object Management Group -2, 2013). Pros and Cons of Chen’s Modeling Technique The biggest advantage of Chen’s Modelling technique is that it played a major role in the process of moving conceptual modelling in a practical database design area by laying the basic building blocks, which comprised mainly of entities and relationships. Though there have been significant improvements that have been incorporated in the Chen’s model, yet all the latest and most modern ERD tools has their conceptual origins based in the Chen model (Rob and Coronel, 2009, p. 130). The negative factor of Chen’s modeling technique is that there is a limitation in regards to constraint representation. Also, there is a significant amount of limitation that exists for relationship representation. Also, it needs to be stated that there is a limited amount of space that is available for drawing large number of entities. Pros and Cons of OMG’s UML The positive side of Object Management Group’s Unified Modeling Technique is that instead of modeling entities, it focuses on modeling object classes. Also, another advantage is that the mix and high level of flow of ideas and techniques has resulted in the process of UML becoming a standard notation for representing the data structure in the entire object oriented community in the near future. Another positive advantage of OMG’s UML is that it allows multiple inheritance and multiple type hierarchies. Another advantage is that the OMG UML allows the attributes to be described and explained in more detail than in other notations. The negative side of OMG’s UML is that it should not be used for a physical design model. Also, another negative side of OMG’s UML is that it is mainly a simple design tool and nothing more than that (Hay, 1999, p. 35-36). Graphics Chen’s Model Fig: 1. Source: Chen, 1977, p. 11 Fig: 2 Source: Chen, 1977, p. 13 Fig: 3 Source: Chen, 1977, p. 14 OMG’s UML Fig: 2 Source: uml-diagrams.com, n.d. Source: Haan, 2008 Reference Object Management Group -1. (2013). Getting Started With UML. Retrieved from: http://www.uml.org/ Object Management Group -2. (2013). Getting Started With UML. Retrieved from: http://www.uml.org/ Chen, P. (1977). The Entity-Relationship Model:Toward A Unified View Of Data. USA: MIT Haan, J.D. (2008). Combining general purpose languages and domain specific languages for Model Driven Engineering. Retrieved from: http://www.theenterprisearchitect.eu/archive/2008/04/15/combining_general_purpose_lang uml-diagrams.com. (n.d.) UML, Meta Meta Models and Profiles. Retrieved from: http://www.uml-diagrams.org/uml-meta-models.html Hay, D.C. (1999). A COMPARISON OF DATA MODELING TECHNIQUES. Retrieved from: http://csis.bits-pilani.ac.in/faculty/goel/course_material/Data%20Warehousing/II%20sem%202004-05/Assignmet%201/comparison%20of%20DM%20techniqus.pdf Rob, P. and Coronel, C. (2009) Database Systems: Design: Design, Implementation, and Management. USA: Cengage Learning. Read More