Explain Different Types of Attributes in Er Model

This is an independent type of entity that does not depend on anyone. In ER diagram key attribute is.

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Generally it is not recommended to give attributes to the relationships if not required because while converting the ER model into Relational model.

. There are four types of attributes. Key Attribute The attribute which uniquely identifies each entity in the entity set is called key attributeFor example Roll_No will be unique for each student. In the model entity relationship there are two kinds of entity types.

ER-Diagram is a pictorial representation of data that describes how data is communicated and related to each other. In ER diagram attribute is represented by an oval. The fundamental steps are same regardless of where youre working.

In ER diagram key attribute is represented by an oval with underlying lines. A rectangle is the symbol of the entity and should be given. In ER diagram attribute is represented by an oval.

In the ER model the attributes are the fields that are related to entity and used for describing the property of entity. The entities and the relationships between them are demonstrated by using the ER symbols part of ER diagram to show various kinds of entities attributes identifiers and relationships. The attributes with values that are atomic and cannot be broken down further are simple attributes.

Identifying relationship Type as double lined diamond shaped Box. Types of Attributes simple single-valued attributes simple multi-valued attributes composite single-valued attributes composite multi-valued attributes. Attributes Types In ER Diagram It is believed that the ER Diagram can be a powerful tool in data mining.

Any object such as entities attributes of an entity sets of relationship and other attributes of relationship can be characterized with the help of the ER diagram. In ER model entities have attributes which can be of various types like single-valued multi-valued composite simple stored derived and complex. A superkey of an entity set is an attribute or set of attributes with values that uniquely identify each entity in the set.

For example a person can have only one gender and one date of birth. In this example License is a superkey as it is a unique identifier. It is also called an atomic attribute.

But relationships can also have attributes associated to them. An attribute that composed of many other attributes is known as a composite attribute. For example phone numbers.

An attribute can be of many types here are different types of attributes defined in ER database model. The key attribute is used to represent the main characteristics of an entity. Types of attributes.

Weak entity Type as double lined Rectangular Box. The attribute of an entity that can be divided into smaller component is called composite attribute. Superkey Candidate Primary and Alternate Key.

This type of entity is dependent on a strong entity. Composite attribute The attributes which can be further divided. For example Roll_No Name DOB Age Address Mobile_No are the attributes which defines entity type Student.

Each component also represents simple attribute with independent meaning in the elements of the E-R Model of the same data file. Attributes are the properties which define the entity type. Simple Attributes- Simple attributes are those attributes which can not be divided further.

Entity Type as Rectangular Box. Multivalued attribute They contain more than one value of a single entity. An attribute describes the property of an entity.

The database structure utilizing the ER Model is typically demonstrated pictorially by the means of entity-relationship ie. For example age salary etc. For example students name can be divided into first name middle name and last name.

Types of Attributes- In ER diagram attributes associated with an entity set may be of the following types- Simple attributes. In a weak entity set it. The composite attribute contains more than one attribute in the group.

Single value attribute These attributes contain a single value. For example employee entity the employee name employee age employee number can be considered as attributes for employee entity. For example students age.

For example a DMV database might contain the following information. An attribute is represented as Oval in an ER diagram. For example the employee name attribute can be considered.

Multivalued attributes are modeled in ER using a double circle. They are represented using the rectangle-shaped box. Identifying Entity Types in the ER Model.

It allows users to see complicated relationships in a straightforward format. Relationship Type as diamond-shaped Box. Derived attributeThe value for this type of attribute can be derived from the values of other related attributes or entities instances.

The types of attributes in the Entity Relationship ER model are as follows. The simple attribute can be considered as atomic values that cant be further segregated. It represents a primary key.

First you must to determine what your system is. An attribute that cannot be subdivided into smaller components is known as a simple attribute. For example Roll_No Name DOB Age Address Mobile_No are the attributes which defines entity type Student.

Figure 1 shows the notation for a weak and strong entity type in the ER-model. 4 rows Primary Key is one of its attributes which helps to identify its member. Attribute names enclosed in ovals and attached to their entity type by straight lines.

For example the employee phone number cannot be further segregate to some other attribute. The attributes are represented by eclipse in ER model. A person may have zero one or more phone numbers and different employees may have different numbers of phones.

Click to see full answer. Different types of attributes are represented in the E-R diagram as follows. The key attribute is represented by an ellipse with the text underlined.

Key attribute names enclosed in ovals and.

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