3. Why it is invalid to ask for the first row in a relational table. (10 pts) 4.

Question

3. Why it is invalid to ask for the first row in a relational table. (10 pts)

4. Give a relational database schema for a department-student database. Every department has a unique department number, a name and several contact phone numbers. Every student has a student id, a name (first and last), and a corresponding department. In the database schema, you should indicate the keys and foreign keys wherever applicable. (40 pts)

Note: Database schema includes the definition of the relation as well as all database constraints. For simplicity, the domain for each attribute can be omitted in the schema. The database schema should use the following format for each table:

Relation_name (attribute name list), PK: ..., FK (if any): ... refs ...

For example:

Project (ProjectNo, ProjectName), PK: ProjectNo.

Employee (EmployeeNo, Name, WorksOn), PK: EmployeeNo, FK: WorksOn refs Project.

Explanation / Answer

3.
It is not invalid to ask for the first row in a relational table unless you are using the proper syntax and proper conditions to fetch the first row. Or maybe you want to ask something else. For that you'll have to give more explanation.

4.
department(departmentNumber, departmentName, phoneNumber) PK: departmentNumber
student(studentId, firstName, lastname, departmentId) PK: studentId, FK departmentId refs department.departmentNumber

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