The purpose of a database is to store information about certain types of objects or entities.
Entity Class = Table name.
Entity=a data / row of a table.
Entity Set = set of data / rows In table.
Attributes are used to include information that we want in the database. Attributes = Field, Columns
The Entity-Relationship Model Of A Database Sample
LIBRARY database
- Books entity class.
- ISBN attribute.
- Title attribute.
- Price attribute.
- Authors entity class.
- Author_Id attribute.
- Author_Name attribute.
- Author_Phone attribute.
- Publishers entity class.
- Publisher_Id attribute.
- Publisher_Name attribute.
- Publisher_Phone attribute.
- Contributors entity class.
- Contributor_Id attribute.
- Contributor_Name attribute.
- Contributor_Phone attribute.
Table Scheme
Syntax:
Table_Name ( Field_Name_1, Field_Name_2, ... )
Example:
Entities And Attributes List:
Authors (AuID#,AuName,AuPhone)
BookAuthor (ISBN,AuID)
Books(ISBN#,Title,PubID,Price)
Publishers (PubID#, PubName, PubPhone)
Contributors (Contributor_Id#, Contributor_Name, Contributor_Phone)
# is notation to primary key
to read about foreign key notation, click : Entity Relationship Diagram ( ERD ) 2 >
to read about DDL, DQL, DML, DCL and TCL Commands, click : DDL, DQL, DML, DCL and TCL Commands >
Bibliography
Introduction To Database Management System;Dr. Satinder Bal Gupta et. al.;University Science Press
Access Database Design &
Programming;Steven Roman;O'Reilly
ERM, Entity Relationship Diagram, erd, data column, data row, program design, table sample, software design, application design
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