ER Diagram GenERalization And Specialization – It is believed that the ER Diagram can be a powerful tool in data mining. It allows the visualization of complex relationships in a simple format. The basic steps are the identical regardless of the place you’re working. It starts by identifying “what” your system is. A rectangle represents the entity, and it should be given ample space. After that, add ovals to represent attributes and connect them with the entity. There should be a gap between each rectangle.
Each of the entities on one ER diagram is called an attribute. The term “attribute” refers to a property or trait that an individual entity has. In the case for an ER diagram an inventory Item Name is one of the attributes belonging to an inventory Item. The item can be equipped with as many attributes as it requires, and each attribute can have specific attributes. For example, a customer’s address can be identified by a street number as well as a city and state. They are composite attributes which means there aren’t restrictions in the amount of each.
The next stage in the analysis of an ER diagram will be to identify the amount of information that each entity is able to provide. The cardinality of an individual is the number of factors that exist within two separate entities. For example, a customer could purchase several phones through the same service on one phone, and the cell phone provider may have several phones under one bill. The ER diagram can help make it easier to identify how the entities are connected. Furthermore, it could help you to determine what data is the basis of each entity.
As the system expands and gets more complex the ER diagram may become crowded and difficult to understand. The complexity associated with the ER diagram requires more detailed representation of the micro-level. A properly designed ER diagram will allow you to comprehend a system in a greater depth. Make sure to include white space between the tables of your ER diagram to avoid confusion. If you don’t, it will be difficult to identify the relationship between two entities.
A person is a person. An entity is a thing or a class. An entity could be an individual or a city or even an organization. An entity that is weaker is one that is dependent on anotherentity, but lacks the most important attributes. A characteristic is the property of an object. The person who is in the ER diagram is an adjective. Similar to the city, it has a status of an organization. The reason why a connection is established between two entities is an adjective.
The characteristics included in an ER diagram need to be labeled. For example, a school entity may have several subject values. Students may have several subjects. The relation between two people is illustrated by diamond-shaped shapes. Usually, these lines will be described with verbs. They are then identified as entities. If a student is confused on the meaning of an attribute and is unsure of its meaning, the ER diagram can help them understand the relation between two things.
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