Describe Relational Concepts DP-900 Practice Questions (Page 8)

Questions 36–40

1. 36foundation · easy

   In a relational database, which of the following best describes the structure of a table?

   • AA hierarchical tree of parent-child nodes
   • BA set of rows and columns where each row represents an entity instance and each column represents an attribute
   • CA collection of documents with flexible schemas
   • DA collection of related data stored as key-value pairs
   Reveal Solution Discussion Select an answer first
2. 37foundation · easy

   What does the following SQL statement do? INSERT INTO Customers (CustomerID, Name) VALUES (1, 'John');

   • AAdds a new row to the Customers table with CustomerID 1 and Name 'John'
   • BUpdates the Name of CustomerID 1 to 'John'
   • CSelects the customer with CustomerID 1
   • DDeletes the customer with CustomerID 1
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4. 38application · medium

   A startup is building a customer relationship management (CRM) system. They currently store customer data in a single spreadsheet with columns for CustomerID, CustomerName, OrderID, OrderDate, OrderTotal, and ProductName. Each customer can place multiple orders, and each order can contain multiple products. The team notices that when they update a customer's phone number, they must update it in multiple rows. They want to redesign the data storage to eliminate this redundancy. Which approach best addresses their requirement?

   • ACreate one table per customer to store their orders and products.
   • BStore all data in a single table but use a composite primary key on CustomerID and OrderID.
   • CKeep the single spreadsheet but add more columns for each possible product.
   • DCreate separate Customer, Order, and OrderItem tables, linking them with foreign keys.
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5. 39application · medium

   A database has a table named EmployeeAudit that records every change made to the Employees table. The business requires that whenever a new employee is inserted, a row must automatically be added to EmployeeAudit with the current date and the username of the person who performed the insert. What should be created to meet this requirement?

   • AA view that joins Employees and EmployeeAudit.
   • BA trigger on the Employees table that fires AFTER INSERT.
   • CA stored procedure that applications must call after every insert.
   • DAn index on the EmployeeAudit table.
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6. 40application · medium

   A retail company stores customer orders in a relational database. Each order must be linked to exactly one customer, and each customer can have many orders. The Orders table currently has columns: OrderID, OrderDate, CustomerName, CustomerEmail, and CustomerPhone. The database designer wants to enforce the relationship between Orders and Customers without duplicating customer data. What should the designer do?

   • AAdd an OrderID column to the Customers table as a foreign key referencing the Orders table.
   • BCreate a new table called OrderCustomers with OrderID and CustomerID as a composite primary key.
   • CAdd a CustomerID column to the Orders table as a foreign key referencing the Customers table.
   • DKeep CustomerName, CustomerEmail, and CustomerPhone in the Orders table and add a primary key on CustomerEmail.
   Reveal Solution Discussion Select an answer first