I would love to answer your. . . sentence but it isn't a question.
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ENHANCED ENTITY RELATIONSHIP OR EXTENDED ENTITY RELATIONSHIP
If you have a many-to-many relationship between two entities you create an intermediate entity between.Now, the relationship between the first entity and intersection entity is one-to-many, and the relationship between the second entity and intersection entity is one-to-many also.
An entity relationship diagram for hotel reservation systems is a map of each entity or thing that has a part in the process of hotel reservations. The diagram maps the relationship between each entity of the process.
An entity relationship diagram (ERD) represents the entities, or groups of information, and their relationships maintained for a business. An entity relationship diagram represents the entities, or groups of information, and their relationships maintained for a business. An entity relationship diagram represents the entities, or groups of information, and their relationships maintained for a business.
In contrast to the strong or regular entity, a weak entity is one that meets two conditions: 1. The entity is existence-dependent; that is, it cannot exist without the entity with which it has a relationship. 2. The entity has a primary key that is partially or totally derived from the parent entity in the relationship.
It will be a recursive relationship.
relationship.....
entity relation model for hospital database
Entity-Relationship diagrams are useful for modelling data and the relationships between the data. They can be used when the constraints between data are relatively simple. They do not allow specification of interactions between the data or model how the data changes (there are no processes in Entity-Relationship). Entity-Relationship diagrams are most often used to model databases.
Participation (or optionality) concerns the involvement of entities i a relationship. Participation is about exceptions to the rule. An entity's participation is optional if there is a least one instance of an entity which does not participate in the relationship. An entity participation is mandatory if all instances of an entity must participate in the relationship.
it is a unary relationship.
A relationship with attributes should be an associative entity when: - All relationships for the associative entity should be many - The associative entity could have meaning independent of the other entities - The associative entity should have attribute(s), but it may or may not have an identifier - The associative entity may participate in other relationships other than the entities of the associated relationship - Ternary relationships should be converted to associative entities