Data Models
Data Models
A model is a representation of reality, ‘real world’ objects and events, and their associations. It is an abstraction that concentrates on the essential, inherent aspects of an organization and ignore the accidental properties. A data model represents the organization itself. Let should provide the basic concepts and notations that will allow database designers and end users unambiguously and accurately to communicate their understanding of the organizational data.
Data Model can be defined as an integrated collection of concepts for describing and manipulating data, relationships between data, and constraints on the data in an organization.
A data model comprises of three components:
• A structural part, consisting of a set of rules according to which databases can be constructed.
• A manipulative part. Defining the types of operation that are allowed on the data (this includes the operations that are used or updating or retrieving data from the database and for changing the structure of the database).
• Possibly a set of integrity rules, which ensures that the data is accurate.
The purpose of a data model is to represent data and to make the data understandable.
There have been many data models proposed in the literature. They fall into three broad categories:
• Object Based Data Models
• Physical Data Models
• Record Based Data Models
The object based and record based data models are used to describe data at the conceptual and external levels, the physical data model is used to describe data at the internal level.
A model is a representation of reality, ‘real world’ objects and events, and their associations. It is an abstraction that concentrates on the essential, inherent aspects of an organization and ignore the accidental properties. A data model represents the organization itself. Let should provide the basic concepts and notations that will allow database designers and end users unambiguously and accurately to communicate their understanding of the organizational data.
Data Model can be defined as an integrated collection of concepts for describing and manipulating data, relationships between data, and constraints on the data in an organization.
A data model comprises of three components:
• A structural part, consisting of a set of rules according to which databases can be constructed.
• A manipulative part. Defining the types of operation that are allowed on the data (this includes the operations that are used or updating or retrieving data from the database and for changing the structure of the database).
• Possibly a set of integrity rules, which ensures that the data is accurate.
The purpose of a data model is to represent data and to make the data understandable.
There have been many data models proposed in the literature. They fall into three broad categories:
• Object Based Data Models
• Physical Data Models
• Record Based Data Models
The object based and record based data models are used to describe data at the conceptual and external levels, the physical data model is used to describe data at the internal level.
Leave a Comment