Database Concepts: Relational vs. Non-Relational, Tables, Rows, Fields, Primary/foreign Keys. IT-FUNDAMENTALS-ITF-CERTIFICATION Practice Questions (Page 5)

Questions 21–25

1. 21expert · hard

   A company needs to store product data for an e-commerce site. The data includes a fixed set of attributes (ID, Name, Price) and a variable set of attributes (e.g., color, size, material) that differ by product category. They also need to run reports that aggregate sales by product category. The team is considering a relational database with a product table and a separate table for variable attributes, versus a non-relational database with a flexible document for each product. What is the most significant trade-off between these two approaches?

   • AThe non-relational approach will have a rigid schema, making it difficult to add new product attributes.
   • BThe relational approach requires complex joins to retrieve a complete product, while the non-relational approach stores all product data in one document.
   • CThe non-relational approach will require more storage space because of data duplication.
   • DThe relational approach is always faster for reporting and aggregation queries.
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2. 22expert · hard

   A database has an 'Orders' table and a 'Customers' table. The 'Customers' table has a primary key 'CustomerID'. The 'Orders' table has a foreign key 'CustomerID'. The company decides to delete a customer who has placed orders in the past. What is the most important consideration regarding the foreign key constraint when deleting this customer?

   • AThe deletion will always fail because of the foreign key constraint.
   • BThe deletion will automatically delete all of the customer's orders if the foreign key is defined with ON DELETE CASCADE.
   • CThe deletion will be successful, but the orders will remain with a NULL CustomerID.
   • DThe deletion will be successful, but the orders will become orphaned.
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4. 23application · medium

   A database has a 'Courses' table with 'CourseID' as the primary key. A new 'Enrollments' table is created to track which students are enrolled in which courses. The 'Enrollments' table will have 'EnrollmentID' as its primary key. What columns should be added to the 'Enrollments' table to link it to the 'Courses' table and a 'Students' table?

   • ACourseID and StudentID
   • BCourseID and EnrollmentID
   • CStudentID and EnrollmentDate
   • DCourseName and StudentName
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5. 24foundation · easy

   In a relational database, what is a field?

   • AA database query that retrieves specific data.
   • BA column in a table that holds a specific attribute for each record.
   • CA relationship between two tables.
   • DA row in a table that represents a single record.
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6. 25application · easy

   A library database has an 'Authors' table with a primary key 'AuthorID' and a 'Books' table. Each book is written by exactly one author. To link each book to its author, which column should be added to the 'Books' table?

   • ABookID
   • BAuthorID
   • CBookTitle
   • DAuthorName
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