Library Database System Basics

Answers and Descriptions:

1. Answer: The main purpose is to track books and their borrowers, ensuring efficient management of library resources.
   Description: This database helps librarians know which books are available, who has borrowed them, and when, reducing manual tracking errors and improving efficiency.
2. Answer: “BookID” is unique for each book, ensuring no two books have the same identifier, which prevents duplication.
   Description: A primary key like “BookID” (e.g., 1, 2, 3) uniquely identifies each record. Titles or authors could repeat (e.g., multiple books by Tolkien), but “BookID” cannot.
3. Answer: “CopiesAvailable” is a numeric value (e.g., 5, 3) that may need calculations (e.g., subtracting when borrowed), which requires a Number data type.
   Description: If it were Text, you couldn’t perform math operations like reducing stock when a book is borrowed. Number ensures functionality in an electronic system.
4. Answer: “BookID” is the primary key in “Books” and a foreign key in “Borrowers,” linking each borrowed book to its details in the “Books” table.
   Description: For example, BorrowerID 101 (Alice) has BookID 1, which matches “The Hobbit” in the “Books” table, showing what she borrowed.
5. Answer: In the DBMS, drag “BookID” from the “Books” table to “BookID” in the “Borrowers” table in the Relationships window to create a one-to-many link.
   Description: One book (e.g., BookID 1) can be borrowed by many students (e.g., Alice and Clara), and the DBMS enforces this link to maintain data integrity.

Question Title: Advanced Library Database Operations

Answers and Descriptions:

1. Answer: “The Hobbit” (BookID 1) has been borrowed twice (by Alice and Clara), confirmed by checking the “BookID” in the “Borrowers” table.
   Description: The relational link shows BookID 1 appears in two records (BorrowerID 101 and 103), proving its popularity without needing manual counts.
2. Answer: The DBMS would reject the record or show an error because the foreign key “BookID” must match an existing primary key in “Books” to maintain referential integrity.
   Description: If BookID 4 isn’t in “Books,” adding it to “Borrowers” would break the relationship (e.g., no book details exist), so the system prevents this.