Assuming there is a 1:M relationship between entities Project and Employee. The

Question

Assuming there is a 1:M relationship between entities Project and Employee. The minimum cardinality is O:M ( optional : mandatory) . Feel in the following table by indicating how a database system maintains the data integrity.

When

What a system* does on parent

What a system does on child

Delete an employee

Add an employee

Delete a project

Add a project

Update key of project

Update foreign key of employee

Update primary key of employee

*Note: The system here is a well design and developed database system and its applications.

When

What a system* does on parent

What a system does on child

Delete an employee

Add an employee

Delete a project

Add a project

Update key of project

Update foreign key of employee

Update primary key of employee

Explanation / Answer

Please find my answer below

-----------------------------------------------

When What a system* does on parent What a system does on child Delete an employee can be deleted can be deleted Add an employee can be added can be added Delete a project can not delete if child exists , if child does not exist then only can delete can be deleted Add a project can be added can not add if the parent does not exists Update key of project can be updated can be updated Update foreign key of employee can be updated can be updated Update primary key of employee can update so that to form uniqueness on the primary key or unique key columns else can not update can update so that to form uniqueness on the primary key or unique key columns else can not update

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.