ERD

Designers Must Do the Modeling {2}

by Asim K

In his article Designers Must Do the Modeling, which was published in IEEE Software , Volume 15 Issue 2, Brian Lawrence enunciates on the fact that designers for database, or any other project, must do the modeling. Lawrence defines the stepping stone as figuring out the customer’s problem rather than figuring out requirements for the project. In his logical breakdown, Lawrence cites ERD models as only an output of the requirements process which will dictate database  design later on in the process. He pursues this opinion with another, saying that producing the ERD diagram (or whichever type of diagram you may be working with) has the benefit of allowing ourselves to understand the customer’s problem better so we can design better solutions. Because the designers have to produce the requirements model, Lawrence embraces the not-so-popular opinion that the designers themselves are the owners of the model.  Citing a quote by Dwight Eisenhower, the author embraces the planning process over the actual plan. To further reinforce this statement, Lawrence says that managers must help persuade designers to understand that they must model requirements – no matter if the designers see it as their duty or not. Similar to the statement of “Learning by Doing”, Brian Lawrence embraces a brilliant model in saying that it is during the planning phase that we learn the most, not in the implementation of the plan. Personally, I agree with this worldview because I have experienced the  same euphoria myself. When I was younger, around 11 or 12, years old I would sit down to learn HTML as a hobby (yes, HTML was my hobby). Although my websites churned out to look like absolute trash and functioned on a pretty depressing level, in the process of research, working with clients, figuring out bells and whistles, I was able to generate a more holistic understanding  of what I was learning and still retain that knowledge today. On these terms, I agree that the designers – the individuals who actually work with the client to figure out their problems and solve them – are the people who should create the requirements needed for their projects; in our case: a databaase. Lawrence, B. (1998). Designers must do the modeling. Software, IEEE, 15(2). Retrieved from http://0-ieeexplore.ieee.org.opac.library.csupomona.edu/stamp/stamp.jsp?tp=&arnumber=663782.

An Education in Notation {2}

by Brian B
The article I chose this week is entitled “Notation Usage in Data Modeling Education” by Michael Mannino. The article starts off by saying that there has never been a true standard of notation in the data modeling field. There have been attempts in the past, but none of them have ever gained wide usage throughout the industry.  He talks about the fact that there is a wide variety of notation styles which has been increased with the differences in textbooks and the CASE Tools used in the industry. The author believes that creating a standard now would be difficult because of the current “diversity” in modeling notation. The author says that students should be taught both ERD and UML, however they should be taught in separate classes. The article goes on to talk about ways to instruct students in subject matter such as design errors or advancing their knowledge in data modeling. He finishes the article off by saying that “These guidelines are just building blocks to develop data modeling skills. (Mannino, Spring 2006)” He then offers some ideas on how data modeling education can be advanced. One way he suggests is that students be given real world examples of data modeling to actually prepare them for what is in store for them in their field of work. read more...

New Way to Model Data {3}

by Andrew M
The article I read this week was entitled “Software Tool for Automated Analysis of Conceptual Data Model” by Z. Kazi and B. Radulovic. This article goes over the idea that databases can be majorly improved if they are efficiently and correctly made from the get go. The authors point out that many times there are issues created because the admins who are creating the database either do not have the knowledge or the skill to create the initial data model correctly. The proposed solution is to use a few tools to help enable database admins to create better and more efficient databases. The first tool they suggest using is CASE. This software tool helps to create the actual data model itself in the correct form. Next, a tool named PROLOG is used which actually tests the model and gives back input. This program shows the relationships that the user has modeled and also how they relate to each other. PROLOG prints out a form in which it can show attributes of a certain entity and also the rules governing that specific entity. The authors feel that if these tools are used that databases can be created much more efficiently. read more...

Normalization… Why? {1}

by Evin C
Normalizing data has become an important aspect of our course which is why I chose this article. Looking through the full article not only gives you a perspective on normalizing data but also unique ways to approach it. Having already gone over the ways to normalize data in class, this summarizes that information yet again to hopefully appeal to more people and help everyone better understand the process. Although it does not have labeled examples, it does have in depth details about each individual normal form and how they are converted and applied. The article then goes on to evaluate how accuracy and performance affect a database, saying “a poorly normalized database and poorly normalized tables can cause problems ranging from excessive disk I/O and subsequent poor system performance to inaccurate data.” It even goes on to say “an improperly normalized condition can result in extensive data redundancy, which puts a burden on all programs that modify the data.” read more...

Create An Effective Data Model For Your Database {1}

by Toan T
This article talks about how a newly developer such as myself that have never build database before can build an actual database that is functional and efficient at the same time. Database development of today is somewhat different from what have been done in the past, companies are often cutting costs which mean that the modeling process might require heavy modifications. This article provides the fundamental concepts that can help anyone create a data model that fits his/her needs.
There are three stages to developing a database: Planning, Design and Deployment. In the real world when a database will be used for a single application, planning usually receive less attention and most of the work lies within the design and deployment phases. The article also heavily emphasize on three concepts that would help create a more logical quality to the data that would promote re-usability. Conceptual Data Model or CDM for short is a effective data model that heavily emphasized on business rules. This usually includes ERD that help describe the business steps that occur within an organization. In other words, data is created and attributes are identified. The second model is Logical Data Model where the database involving CDM is taken and get translated into an empirical layout of the data. This is when the all the data that was from CDM get transferred and then process by applying them into a normalized layout. The last model is the Physical Data Model where everything that was developed in the last two models get brought together into a final layout of tables where columns, index and constraints are defined. read more...

Breaking Down Relational Databases {1}

by Evin C
The article I have chosen is a peer reviewed article from Kansas State University about how students conceptualize entity relationships. This article explains in depth how entity relationship design can vary from student to student and not one individual way is correct. It goes on to explain and give examples of how the way we perceive these relationships can ultimately affect our work beyond college. Depending on how specific we are with these relational entities or how general we are can show if we will miss important concepts within a business that will affect efficiency. Examples are given from using associative entities in a business to applying an ERD to relational model. Michael Chilton uses this article to explain how us as students need to be aware of the environment we are working in as well as the situation at hand because there is no one way to create an entity relationship. As a student we have to thrive to understand the basic concepts and use them to our advantage in the real world. read more...

Time to move on to something…better {1}

by Stephen O
Summary:

When is it time for something new? When is a good time to trade up? Is it similar to buying a smart phone? Waiting for the new model later that year? Is it when the industry chooses a standard like Blue Ray or VHS? On the other hand, is it like buying a car and it no longer can perform reliably the duties we purchased it for? When is it time for us to transition to the next generation of Data Modeling?  In the article “Toward a Next Generation Data Modeling Facility: Neither the Entity-Relationship Model nor UML Meet the Need” the author went about explaining why perhaps it is time to move on towards the next generation of Data Modeling.  They defined five wanted characteristics of a Data model. read more...