6.4: Modeling

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Finally, speaking of data, entities and variables might have relationships to other entities, so this should be the last phase of ER diagram assembly. Take, for example, the order and customer entities in the context of the company. The relationship is as such, for each customer, they may have multiple orders, while each order will only have one customer who made it. The storage facility may have multiple incoming orders or requests, but the order only references one facility.

Figure \(\PageIndex{1}\): Entity-to-Entity Relation. ("Module_2 - Relationship Diagram for Data Analysis & SQL" by Dr Sarah North, Affordable Learning Georgia)

Thus we can see the importance of properly laying out and describing ER relations to better represent the data. However, let’s address some smaller, more technical issues that may arise when creating a diagram. Given a diagram, sometimes concepts or variables put onto the board that others are not familiar with. Say you use some in-house acronyms at a large event, and then people ask questions about those topics. That is wasted time that could have been spent asking better questions that you prepared to answer. Remember that while you want to inform your audience, it is important to present that in an easily comprehendible way. Following some commonly used conventions, as well as using some advice outlined above, will allow you to work smarter, not harder.

Figure \(\PageIndex{1}\): Store ER Diagram. ("Module_2 - Relationship Diagram for Data Analysis & SQL" by Dr Sarah North, Affordable Learning Georgia)