![]() Value of Age attribute can be derived from Date of Birth attribute, so age is known as derived attribute.ĭerived attributes are represented using dotted line oval.Īttribute which will be used to uniquely identify data (records) of an entity is known as primary key attribute. Multivalued attribute are represented using double line oval.Īttribute whose value can be derived from another attributes are known as derived attribute.Į.g. Mobile No, Phone No can have multiple value, as person can have more than one mobile or phone number. Sub attributes of composite attribute are connected with attribute using a line.Īttribute which may have more than one value are known as multivalued attribute.Į.g. Hence this type of attributes are known as composite attribute. Address attribute can be divided into sub attribute like apartment name, street address, city, pin code name attribute can be divided into sub attribute like first name, middle name, last name.Į.g. Composite AttributeĪttribute which can be further divided into sub attribute are known as composite attribute.Į.g. Simple - Single Value AttributeĪll simple attribute which contains a single value is known as a simple or single value attribute.Į.g. Attributes are connected with entity using a line.Īttributes of entity can be categorized into several types.Attributes of entity are represented using oval/ellipse symbol.Each entity in ER Diagram is represented using rectangle shape with name of entity written on the rectangle.For example, employee entity can have attributes like name, salary, organization, department etc.(in short attributes defines the detail of entity) Attributes is used to define the different type of data of the particular entity.For example, each Employee in a firm is an entity. ![]() An entity is generally a “thing” or “object” of real world which is present in the context.It uses different types of symbols to represent various instances of database.It is a graphical or a pictorial representation of a database.Stands for Entity-Relationship diagram.
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