by Stefan S
This article talks about the importance of primary key in data modeling. Selecting a unique primary key is very important because without a unique primary key or a weak key an attribute might share the same value .The article also talks about the importance of cardinality. Cardinality is a critical aspect of database design. Cardinality is very important in database design because it creates links from one table to another in a structure manner. Without cardinality there will not be any relationship from one entity to another. Examples of two entities are student and the class courses. The cardinality between the student and class course is student can take many courses, which fall under the one to many relationship.
This article can relate to this class because it always reminds us how important it is to have a unique primary key when making a entity table. When making a table we are trying to avoid double entry. We also learn about the different kinds of cardinalities, which include the one to one, one to many, and many to many relationships.
When making data modeling we should remember about normalization or breaking down the entities. It is very important for us to remember normalization so we will have a strong choice of primary key. Overall this article is a good review to what we have learned in class and definitely something I can use to help me understand more about the importance elements in database.
Gravelle, R. (2010, October 08). Cardinaltiy in mysql data modeling. Retrieved from http://www.databasejournal.com/features/mysql/article.php/3906761/Cardinality-in-MySQL-Data-Modeling.htm