An entity relationship diagram, or ERD, is a visual representation of data that also shows how that data is connected. Just like with swim lane diagrams, symbols make it much easier to differentiate the various pieces of data and their relation to others. A rectangle is for an entity, which can be filled in with a noun such as “shopper”. An oval is for the attribute (such as “item price”) and is characterized by an adjective. Lastly, a diamond shows a relationship between two entities and will be characterized by a verb (such as “purchases”). When writing ERD tables, the layout is slightly different, so there are a few things to keep in mind. The entity is written at the top of the table (order, for example), and underneath is where the entity’s attributes are written (item, quantity, etc.). In addition, the relationship/verb is written on the arrow connecting the two entities. Although it may seem like a lot of information, ERDs are pretty simple when you break them down. Overall, they are great for painting a picture of what exactly is going on in a chaotic business environment.
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Hello Madeline,
Great post, ERD’s are a great way to show how different entities and attributes are connected. This always reminds me of swim lanes because it goes into so much detail. Looking at the example you talked about makes it very easy to understand how you can connect one entity with one or many different attributes. It’s important to note that as you said when connecting entities to attributes we must also include a short description as to how the two are connected. This is a great way to keep track of how and why they are connected. Using this in an organization can show an in depth description of who things are connected to one another as well as everything included within that category.