CS409 Introduction to Database Administration is about how a database is structured at different levels and how its parts fit together. Assignment 1 for Fall 2026 carries 20 marks and the due date is 4 November 2026, and it has two questions. The first asks you to identify the DBMS architecture level in three descriptions, and the second asks you to work out the entities, relationships, and a complete ER diagram for a device rental system.
The solution file linked below covers both questions in full. Question 1 is answered with the correct architecture level for each description. Question 2 lists the four entities with their attributes and keys, gives the three relationships with their cardinalities, and includes a complete ER diagram showing the entities, attributes, primary keys, foreign keys, and relationships.
What Does the Solution File Cover?
The file covers the three-schema DBMS architecture and a complete ER design for the device rental system. The architecture answers follow the standard three levels: what the whole database defines, what one user sees, and how data is physically stored. The ER design covers all four entities, their keys, and every relationship between them, with the diagram included so you can see the full design at a glance.
Which Architecture Level Is Each Description?
The company-wide definition of the entities Customer, Device, and Rental, with their attributes and relationships, is the Conceptual Level, because it describes the whole database structure. A customer-specific view that shows only that customer’s current rentals and due dates is the External Level, because it is one user’s view of the data. The DBA selecting disk file organization and creating an index on Rental_Date is the Internal Level, because it is about physical storage and retrieval.
What Are the Entities and Their Attributes?
The system has four entities. Branch has Branch_ID as primary key and Branch_Name. Device has Device_ID as primary key, Device_Name, Daily_Rate, and Branch_ID as foreign key. Customer has Customer_ID as primary key, Customer_Name, and Contact_No. Rental has Rental_ID as primary key, Rental_Date, Return_Date which is optional, and Customer_ID and Device_ID as foreign keys.
What Are the Relationships and the ER Diagram?
All three relationships are one-to-many. One branch can have many devices, but each device belongs to exactly one branch. One customer can have many rental records, but each rental belongs to exactly one customer. One device can appear in many rental records over time, but each rental record refers to exactly one device. The ER diagram in the file shows all four entities with their attributes and keys, connected by these one-to-many relationships.
How Do You Download the Solution File?
You can download the complete solution file from Google Drive using the link below. Read it alongside your own question file on VULMS, and make sure you understand each answer before submitting, since the ER diagram part is best learned by redrawing it yourself once.
How Should You Use This Solution?
A solution file helps most when you use it to learn, not just to submit. First, memorize the three architecture levels with one example each, because that distinction is asked again and again. Then study the ER diagram: cover the relationships and try to name them yourself before checking. Also check your work against the exact assignment file on VULMS, since question wording can vary.
- Learn the three architecture levels with one example each.
- Study the four entities, their keys, and the foreign keys.
- Redraw the ER diagram yourself once before submitting.
- Check every answer against your own question file on VULMS.
For more study material, you can download course handouts from the VU handouts page and compact revision notes from the VU short notes page. Past papers are also useful for database practice, and you can find them on the VU midterm past papers page.
Frequently Asked Questions
Is this the complete solution for CS409 Assignment 1 Fall 2026?
Yes. The file covers both questions: the three DBMS architecture levels, the four entities with attributes and keys, the three relationships with cardinalities, and the complete ER diagram. The assignment carries 20 marks and the due date is 4 November 2026.
What is the difference between the Conceptual and External levels?
The Conceptual Level defines the whole database: all entities, attributes, and relationships. The External Level is one user’s view, showing only the part of the data that user needs, such as one customer’s own rentals and due dates.
Why is the Rental return date optional?
Because a device that is still on rent has no return date yet. The field stays empty (NULL) until the device is returned, which is why it is marked optional in the design.
Last updated: October 2026.
