Unit 1: Basics of Database - Practice Quiz

1 What is a database?

2 Which software is primarily used to create and manage databases?

3 What is a major benefit of using a database?

4 Which application commonly uses a database to store account and transaction information?

5 Which type of database organizes data into tables containing rows and columns?

6 Which type of database stores data in a tree-like parent-child structure?

7 Which database type is designed to represent highly connected data using nodes and edges?

8 In a client-server database architecture, what does the client usually do?

9 Which layer of a three-tier architecture contains the user interface?

10 How many main layers are present in a three-tier database architecture?

11 Which database component contains the actual stored facts, such as customer names and addresses?

12 Who is mainly responsible for database security, backup, and maintenance?

13 Which language is commonly used to query a relational database?

14 What does a database schema describe?

15 In a relational schema, what does an attribute usually represent?

16 Which data model represents information using entities, attributes, and relationships?

17 In the relational data model, what is a single row commonly called?

18 Which design stage identifies high-level entities and relationships without focusing on implementation details?

19 Which design stage converts a conceptual model into tables, keys, and relationships?

20 Which design stage determines storage structures, indexes, and file organization?

21 A university stores student profiles, course registrations, grades, and fee payments in one managed system. What is the primary advantage of using a database for this purpose?

22 An organization replaces separate spreadsheets with a database system. Which problem is most directly reduced by this change?

23 A bank must ensure that a transfer subtracts money from one account only when the amount is added to another account. Which database capability is most important?

24 A hospital system allows doctors, nurses, and billing staff to view different parts of a patient's record. Which database benefit is being applied?

25 A social networking application stores users, friendships, and frequently changing relationships. Which database type is generally most suitable for efficiently traversing these connections?

26 An analytics platform stores sales records in columns and frequently calculates totals for selected attributes. Which database type is likely to provide the greatest advantage?

27 A product catalog contains records with different attributes for different product categories. Which database type can naturally accommodate this variation?

28 In a three-schema architecture, which level describes the complete logical structure of the database for the organization?

29 A change in file organization should not require changes to user applications. Which data independence principle does this illustrate?

30 In a three-tier database application, which layer normally processes business rules between the user interface and the database server?

31 A database administrator creates a rule requiring every employee record to contain a unique employee number. Which database component enforces this requirement?

32 A query runs slowly because the system scans every row to find matching customer IDs. Which database component can improve this operation?

33 After a power failure, the database restores committed changes and removes incomplete transactions. Which component is primarily responsible?

34 A database schema is changed to add a new attribute to the CUSTOMER table, while existing customer rows remain stored. What does the schema represent?

35 A payroll clerk is allowed to see employee names and salaries but not medical information. Which schema concept best supports this requirement?

36 A company models each department as having many employees, while each employee belongs to one department. Which data model is most directly suited to representing these entities and relationships?

37 A database represents data as tables connected through keys and uses relational algebra for querying. Which data model is being used?

38 During which design stage would an analyst identify entities such as STUDENT and COURSE and define their enrollment relationship?

39 An ER diagram is converted into relations with primary keys, foreign keys, and normalized attributes. Which design stage is this?

40 A database designer chooses indexes, partitioning methods, and storage file organizations for a selected DBMS. Which stage is being performed?

41 Two concurrent programs update account balances stored in shared files. Each program validates the invariant that the total balance remains constant, yet interleaving writes can violate it. Which database capability most directly addresses this problem?

42 A payment API may receive the same request repeatedly because clients retry after timeouts. Which database design most reliably prevents the payment from being recorded twice?

43 During a network partition, a replicated database must preserve linearizable reads and reject conflicting writes, even if some reachable replicas cannot process requests. Under the CAP trade-off, which property is being sacrificed?

44 Administrators replace heap files with indexed storage and reorganize disk pages without changing conceptual relations or user views. Which architectural property does this demonstrate?

45 After a crash, committed updates must survive while incomplete transactions must leave no effects. Assuming write-ahead logging, which DBMS component primarily coordinates the required redo and undo operations?

46 A relation named Enrollment is defined with attributes, domains, a composite primary key, and a foreign-key constraint. Its rows change every semester, but the definition remains unchanged. What does the stable definition represent?

47 An application stores entities with varying properties and frequently evaluates variable-length relationship traversals such as friends-of-friends. Which data model is the most natural fit?

48 In an ER model, Dependent is a weak entity identified by owner entity Employee and partial key DependentName. What should identify a dependent after mapping this design to relations?

49 A ternary relationship Supply(Supplier, Part, Project) has no additional cardinality constraints or functional dependencies. Which relational mapping preserves each relationship occurrence without inventing information?

50 An Orders table is commonly queried by broad OrderDate ranges and occasionally by exact CustomerID. Only one clustered index is allowed. Which physical design best matches this workload?

51 A browser must not connect directly to the database, and all clients must share the same authorization and business rules. In a three-tier architecture, where should those rules primarily execute?

52 A distributed relation is horizontally fragmented using mutually exclusive predicates whose disjunction covers every valid tuple. Which operation reconstructs the original relation while preserving duplicate tuples?

53 A DBA adds a secondary index and changes table partitioning. Existing applications and logical queries continue unchanged. Which statement best characterizes these modifications?

54 Product records have deeply nested structures, optional attributes that differ by category, and are usually retrieved as complete aggregates. Which model minimizes impedance between stored and application-visible structure?

55 An EER specialization of Employee into Manager and Engineer is declared total and overlapping. Which population is valid?

56 Let have functional dependencies and . It is decomposed into and . Which assessment is correct?

57 A large table supports frequent predicates of the form , ordered scans, and occasional inserts. Which access structure is generally most appropriate?

58 After data distribution changes substantially, the DBMS repeatedly chooses a nested-loop join although a hash join would be cheaper. Which component most directly makes the incorrect plan choice?

59 An organization needs historical trend analysis over billions of sales records, with infrequent bulk loads and aggregation-heavy queries. Which database design is most suitable?

60 Several autonomous, heterogeneous databases retain local control but must appear through a unified query interface. Which database approach best describes this arrangement?