Answered by Puneet on 2005-05-07 04:21:07: ER - Stands for entitity relationship diagrams. It is the first step in the design of data model which will later lead to a physical database design of possible a OLTP or OLAP database
The Entity-Relationship (ER) model was originally proposed by Peter in 1976 [Chen76] as a way to unify the network and relational database views.
Simply stated the ER model is a conceptual data model that views the real world as entities and relationships. A basic component of the model is the Entity-Relationship diagram which is used to visually represents data objects.
Since Chen wrote his paper the model has been extended and today it is commonly used for database design For the database designer, the utility of the ER model is:
it maps well to the relational model. The constructs used in the ER model can easily be transformed into relational tables. it is simple and easy to understand with a minimum of training. Therefore, the model can be used by the database designer to communicate the design to the end user.
In addition, the model can be used as a design plan by the database developer to implement a data model in a specific database management software.
ER - Stands for entitity relationship diagrams. It is the first step in the design of data model which will later lead to a physical database design of possible a OLTP or OLAP database
The Entity-Relationship (ER) model was originally proposed by Peter in 1976 [Chen76] as a way to unify the network and relational database views.
Simply stated the ER model is a conceptual data model that views the real world as entities and relationships. A basic component of the model is the Entity-Relationship diagram which is used to visually represents data objects.
Since Chen wrote his paper the model has been extended and today it is commonly used for database design For the database designer the utility of the ER model is:
it maps well to the relational model. The constructs used in the ER model can easily be transformed into relational tables. it is simple and easy to understand with a minimum of training. Therefore the model can be used by the database designer to communicate the design to the end user.
In addition the model can be used as a design plan by the database developer to implement a data model in a specific database management software.
E.R Diagram(Entitiy Relationship diagram) means how the different database table related to each other and what r the primary key and foreign key and their relation.
it is the first step of any database project to build E-R Diagram
The Entity-Relationship (ER) model was originally proposed by Peter in 1976 [Chen76] as a way to unify the network and relational database views.
Simply stated the ER model is a conceptual data model that views the real world as entities and relationships. A basic component of the model is the Entity-Relationship diagram which is used to visually represents data objects.
Since Chen wrote his paper the model has been extended and today it is commonly used for database design For the database designer the utility of the ER model is:
it maps well to the relational model. The constructs used in the ER model can easily be transformed into relational tables. it is simple and easy to understand with a minimum of training. Therefore the model can be used by the database designer to communicate the design to the end user.
In addition the model can be used as a design plan by the database developer to implement a data model in a specific database management software.
Entity Relationship Diagrams are a major data modelling tool and will help organize the data in your project into entities and define the relationships
There are three basic elements in ER models:
Entities are the "things" about which we seek information.
Attributes are the data we collect about the entities.
Relationships provide the structure needed to draw information from multiple entities.
The ER Diagrams is the initial process to analaysis a database application and understands the problems related or causes in future with the choosed database application in this satge different components are watched and studied by the dba's and a diagramatical model is designed by descibing entities attributes relationships constraints and some important things related with project data management and data storage there some unique type drawing shapes are used while design the ER- Diagram those shape are defines the various parts of your DB Application. It Must be designed first before going to start minor to major project of work environment and deeply catch everything and also the future scope of the project application.
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