Data Relationships

Overview When planning an information system, it’s important to know the relationship between data elements within a database. Understanding the relations between record types allows you to get the maximum use out of the information stored in the database. The Internet can be a good resource for learning about data relationships. Topics of interest include glossaries of database terminology, articles about data relationships, and graphical depictions of data relationships. One type of graphical depiction is the entity-relationship diagram. Entity-relationship diagrams are an innovative way of representing complex data relationships.

General Information A good place to start looking for information about data relationships, and how they are visually represented, is this link. Next, visit dbforums.com to read about database design, which includes information about data relationships and modeling. Data relationship terms are discussed on the Web page www.cs.unb.ca/profs/fritz/cs3503/erstuff.htm. The Canadian Ministry of Forests (http://www.for.gov.bc.ca/his/datadmin/models/models.htm) provides one of the best sites for data modeling. Another excellent data modeling site is the one hosted by CERN at www.cern.ch/Adamo/guide/Chapter-2.html. 

Entity-Relationship Diagrams First described by Peter Chen in 1976, an entity-relationship diagram (ERD) is a data modeling technique that creates a graphical depiction of data relationships. For a simple description of ERDs and their uses, visit this Techtarget.com page. The Web page databases.about.com/library/glossary/ contains an excellent glossary that includes many terms about ERDs and other related terms. The Wikipedia article “Entity-relationship model”  is a great resource for both basic, and advanced ERD topics. Another way to learn the fundamentals of ERDs is through examples from different real-world situations. Visit www.smartdraw.com/examples/ to view six different ERDs for applications ranging from mapping a hospital’s billing system data, to outlining a restaurant’s management scheme.