304 Attributes of Relationship Types PDF

304 Attributes of Relationship Types * In ER models, relationships between entities can have attributes of their own, known as ** ** ** **...

304 Attributes of Relationship Types * In ER models, relationships between entities can have attributes of their own, known as ** ** ** ** ** ** ** ** ==** attributes of relationship types. **== * These attributes provide additional information about the association between entities. ** ** * ** *** They are especially useful in cases where details about the relationship itself are essential to * ** ** the database structure and cannot be fully represented by entity attributes alone. ** ** ** ** * Understanding Relationship Attributes ** Relationship attributes store properties specific to the interaction between two or more ** * ** entities, rather than to the entities themselves. ** ** ** * These attributes are typically included when the relationship has properties that need to be ** ** * ** ** tracked independently from the entities involved. ** ** * ** Example: ** In an academic database, the relationship between Student and Course is " enrolls ** ** ` ` ` ` ` in." ` This relationship could have attributes such as Enrollment Date and Grade. ** ** ** ** ` ` ` ` Examples of Relationship Attributes ** 1 Enrollment Example: * * ** ** Entities: Student and Course ** ` ` ` ` ** Relationship: " Enrolls in " ** ` `  ** Attribute of Relationship: ** ** ` Enrollment Date : The date when the student enrolled in the course. ` ** ==* Here, Enrollment Date is not specific to the Student or Course entities individually but ** ** ` ` ` ` ** ** ** rather describe the association between them. ** *== ** 2 Employment Example: * * ** ** Entities: Employee and Department ** ` ` ` ` ** Relationship: " Works in " ** ` ` ** Attributes of Relationship: ** ** ` Position : The role or title the employee holds in that department. ` ** * * * * In this case, Position is detail about the relationship "works in" between Employee and ** ` ` ** ** ** ** ` ` ** ** ` Department , not attributes of the Employee or Department entities alone. ` ** * * ** ** ** ` ` ** ** ` ` ** ** **