What is the value of attribute, entity, data?

Attribute, Entity, Data value

Attribute

Fields or items or elements used to express the properties of an entity are called attributes. For example, a teacher's name, address, phone number, department, etc. is an attribute. Attributes can be of two types.

(i) Simple Attributes (eg Name, Address etc.)

(ii) Composite Attributes (eg – First Name, Last Name, Road No., House No., Area etc.).

 Entity

Entity is the main unit required for standard classification of real or non-real objects. The entity may have real presence or it may be based only on concept. Examples of data entities are building, room, chair, business contract, syllabus, machine, employee, country, nation, student, teacher etc. Of course NT will have some properties. Eg - student is an entity whose attributes are student name, roll no, age, class etc.

An entity type or entity set for an organization is a set of similar 'objects' containing data related to that organization. So the entities associated with the subject database to be created are collectively called entity sets.

Identifying and classifying objects from sets of entities is sometimes difficult, as an 'object' can exist in multiple sets of entities simultaneously. For example, a person can be a student and a part-time employee at the same time.

Value

Each attribute used in an entity has a value called a value. For example, name is an attribute whose value can be Srirup, phone number attribute can be value 0170000.