The Main Building Modules of the Entity Relationship Model

1. What atomic number 18 the main building modules of the Entity affinity sample?  reason each one. The Entity-Relationship model is a top-down approach to anatomy database that is based on unambiguously specifiable object. If begins by identifying things that are uniquely appropriateable called entities and relationships among these entities. The main building modules of the Entity-Relationship model are: a. Entities b. Relationships c. Attributes Entities An Entity is a basic object of ER-model which is an object in real number world that can be decided and can exists independently. Relationships Relationship defines the association among dickens entities. Suppose, cast scholar and a differentiate are the two entities. These entities are associated as student studies in class. Hence studies is a relationship between the two entities, student and class. Attributes The properties of the entities are called attributes. For example if we consi der a ener astoundic phone as an entity then each unstable sanitary keep up its own color, design, model company. All these are the attributes of the mobile entity. 2. What is a faint entity, and how is it represented in an E-R draw? part an example. Weak entity is the one that depends on other entities for existence.

A woebegone entity cannot be identifies uniquely as it does not have comfortable entities to form a primitive key. To make it uniquely unidentifiable, anaemic entity instal is associated with another entity set, called identifying or owner entity set. The owner entity set OWNs the we ak entity set. The relationship among the tw! o entity sets is called identifying relationship. The identifying relationship is incessantly many-to-one and its intricacy is total. Although weak entity set is not provided with a primary key, thither is always a need to distinguish among attributes in weak entities. The discriminator is a set of attributes that enable us to distinguish attributes in weak entity set. The discriminator is also called partial...If you necessity to get a full essay, order it on our website: OrderCustomPaper.com

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