Entity Relationship Diagrams

Much of doing business in any field comes down to relationships. When you are able to maintain healthy and functioning relationships between two parties, you will have a far better chance of success in the long term. It is important to note that these ‘relationships’ don’t necessarily have to be between people – in fact, they are often between things or processes that relate to the business. How parts of the organization interface with other parts, or with outside forces, is important to the health of the company.

Entity relationship diagrams allow you to take a visual look at the connections between different parts of your business or any other organizational structure. This approach is helpful in that it allows you as a manager or leader to better understand what is going on within the organization so you can make changes as necessary. When you are caught up in the day to day process of running a business, you might not have time to step back and see how things are really working. Making time for entity relationship diagrams will force you to look objectively at the relationships that are currently in place so you can determine how they can be improved.

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Different Types of Relationships

There are a number of possible types of relationships within any organization – whether you are talking about data that may exist, processes that work with other processes, or even employees with their various supervisors. You will want to identify the types of relationships that you are dealing with so you can then make the best decisions going forward based on the current status of the organization.

In general, there are three different kinds of relationships you will observe – One to One, One to Many, and Many to Many. While relationships within organizations are often complex and even confusing, putting each of them into one of these three categories is a good start at getting a handle on things. It shouldn’t take much time to look at a certain relationship or system and decide which category it belongs in.
Let’s take a closer look at each of these three types of relationships.

One to One

In this relationship, one entity is related directly to one other entity. This is the simplest and most-obvious form of a relationship. Many times, a One to One relationship will be seen in data collection, such as information that you have on your customers. If you have names and email addresses within a database that you use to market to your existing customers, those two entities have a One to One type of relationship. Each name has an email address associated with it, and vice versa. In this way, One to One relationships are rather easy to understand.

Realistically, there probably aren’t too many One to One type of relationships within your organization beyond those that relate to data. Most businesses are far more complex than that, and things don’t usually stay as clean cut as you might like to think. Therefore, the majority of relationships that you observe will probably fall into one of the next two categories.

One to Many

This is a commonly seen type of relationship within an organization. In this case, there is one entity that has a relationship with, and is affected by, many different other entities or items. A good way to think about this relationship is the manufacture of a finished product. While the final item that rolls off the production line might be a single entity, there are undoubtedly many components that went into the creation of that item. Raw materials, employee hours, equipment, and more all played a role in creating that product that will be sent to market.

So, when thinking about a One to Many relationship, it is important that your diagram represents all of the various relationships that the end product has with the inputs along the way. If even one of those inputs is out of place or falls behind, the rest of the process is compromised. For example, if a raw material is late in being delivered to your factory for use in the manufacturing process, it won’t matter if all of the employees and equipment are ready to go – the project can’t move forward. Using an entity relationship diagram is a great way to make sure that you understand exactly what needs to happen for any relationship in the organization to be successful.

Many to Many

The last relationship type is the most complicated – and probably the most common as well. The Many to Many relationship occurs when you have multiple entities in the same group dealing with multiple other entities. So, if you are producing a long list of products to take to market, and each of them deals with a number of various inputs, you could have countless Many to Many relationships taking place. It probably isn’t hard to imagine just how confusing and overwhelming this could be if you weren’t organized. This is exactly why so many organizations use entity relationship diagrams. They permit you to get a quick and easy glance at what would otherwise be a very complicated topic.

A good owner or manager will always understand their own systems to the very highest level possible. Good decisions come from having good information, and building out diagrams to represent all of your processes is a great way to give yourself the accurate information that you need. It is no small task to guide an organization, especially as it continues to grow and evolve over the years. Take the time to form diagrams that represent all of the important relationships within the organization so you can quickly and decisively take action when you feel that something needs correction. Whether you have a bunch of simple One to One relationships to consider, or you have a long list of Many to Many relationships to sort out, your understanding of the business will be better for the experience of creating these diagrams.

Key Points

  • An entity–relationship model is the result of using a systematic process to describe and define a subject area of business data.
  • The data is represented as components (entities) that are linked with each other by relationships that express the dependencies and requirements between them.
  • Entities may have various properties (attributes) that characterize them.
  • An entity–relationship model is typically implemented as a database.

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