Describe Relational Concepts DP-900 Practice Questions (Page 1)

Questions 1–5

1. 1foundation · easy

   Which of the following is a potential trade-off when creating an index on a table?

   • AInability to use foreign keys
   • BDecreased data security
   • CIncreased storage space and slower write operations
   • DLoss of data integrity
   Reveal Solution Discussion Select an answer first
2. 2application · medium

   A small business tracks sales in a single spreadsheet with columns: SaleID, Date, CustomerName, CustomerAddress, ProductName, ProductCategory, Quantity, and UnitPrice. The owner notices that when a customer changes address, they must update many rows, and some products appear with inconsistent category names. The owner asks you to design a relational database to fix these problems. What is the primary benefit of normalizing this data into separate tables?

   • AIt eliminates the need for primary keys in the database.
   • BIt reduces data redundancy and avoids update anomalies by storing each fact once.
   • CIt ensures that all queries return results in alphabetical order.
   • DIt guarantees faster query performance by reducing the number of tables.
   Reveal Solution Discussion Select an answer first
4. 3expert · hard

   A university database has a single table: Enrollments(StudentID, StudentName, CourseID, CourseName, InstructorID, InstructorName, Grade). A student can enroll in many courses, and a course can have many students. Each course is taught by one instructor, and each instructor teaches many courses. The database is experiencing update anomalies: changing an instructor's name requires updating many rows. You are asked to redesign the schema to eliminate these anomalies while preserving all relationships. Which design best achieves this?

   • ACreate separate Student, Course, Instructor, and Enrollment tables, with Enrollment containing only foreign keys and Grade.
   • BCreate Student and Course tables, but keep InstructorName in the Course table.
   • CKeep the single table but add a composite primary key on StudentID and CourseID.
   • DCreate separate tables for Student and Instructor, but keep CourseName in the Enrollment table.
   Reveal Solution Discussion Select an answer first
5. 4application · medium

   A company has a policy to remove all data for customers who have requested to be forgotten. A customer with CustomerID = 208 has no related orders in the Order table. The database administrator needs to remove this customer's record from the Customer table. Which SQL statement should they use?

   • ADROP TABLE Customer;
   • BDELETE FROM Customer;
   • CUPDATE Customer SET Active = 0 WHERE CustomerID = 208;
   • DDELETE FROM Customer WHERE CustomerID = 208;
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6. 5foundation · easy

   What is the purpose of the SQL SELECT statement?

   • ATo insert new rows into a table
   • BTo modify existing data in a table
   • CTo remove data from a table
   • DTo retrieve data from one or more tables
   Reveal Solution Discussion Select an answer first