The Main Building Modules of the Entity Relationship Model

1. What atomic number 18 the main building modules of the Entity production line mock up?  reason each one. The Entity-Relationship model is a top-down approach to anatomy database that is based on unambiguously recognizable object. If begins by identifying things that be uniquely appropriateable called entities and familys 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 distinct and can exists independently. Relationships Relationship defines the association among dickens entities. Suppose, opine savant 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 co nsider a ener astoundic phone as an entity then each mobile sanitary ware 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 plat? 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 primary(a) key. To make it uniquely unidentifiable, anaemic entity instal is associated with another entity set, called identifying or possessor entity set. The owner entity set OWNs the w eak entity set. The relationship among the t! wo entity sets is called identifying relationship. The identifying relationship is invariably 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 requirement to get a full essay, order it on our website: OrderCustomPaper.com

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