An entity is understood to be an individual, place or thing in real life or is conceptual, only existing in a person’s mind. For instance, it may be viewed as an entity subtype of two different entities depending on the interests of the customers. In addition, if it connects the occurrences between two different entities, then it is called a recursive relationship. Based on cardinality and the degree of database normalisation, it might be required to introduce extra entities and relationships.
Go through every one of your entities and determine what attributes they must have. For instance, an entity might be a Ford car, whereas an entity type might be a manufacturer. It’s possible to enter as many entities as you’d like to map here.
There are four forms of relationships. A relationship is denoted by means of a diamond form. So it will be one to one. You will need a means to represent many-to-many relationships. You require a many-to-many relationship that could describe some extra info about that relationship. Optional relationships are often affected by the presence of some other relationship. Optional Relationship An optional relationship between two entities indicates that it’s not essential for each and every entity occurrence to take part in the relationship.