TRB PG Assistant - Object and Object-Relational Databases - concepts and applications One Line Questions & Answers

1. Consider a 'Person' class with attributes 'name' and 'age'. An object 'John' of class 'Person' would have specific values for 'name' and 'age'. What is 'John' called in Object Database terminology? — An Instance (or Object)

2. What is a 'Subclass' in an inheritance hierarchy within an Object Database? — A class that inherits properties from another class.

3. What is a 'Collection Class' in an Object Database? — A class that represents a container for other objects (e.g., lists, sets, arrays).

4. What is a 'Superclass' in an inheritance hierarchy within an Object Database? — A class from which other classes inherit properties.

5. In ORDBs, what does the term 'Object SQL' or 'SQL Object Extensions' refer to? — Extensions to standard SQL to support object-oriented concepts like user-defined types, inheritance, and methods.

6. What is a 'Method' in an Object Database context? — A function or procedure associated with a class that defines its behavior.

7. What is an 'Object-Relational Database' (ORDB)? — A hybrid database system that combines features of both relational and object databases.

8. What is a 'Database Programming Language' (DBPL) in the context of Object Databases? — A programming language that seamlessly integrates database operations and object manipulation.

9. In an Object-Relational Database, what is a 'Type Extender'? — A mechanism to extend the relational model with new data types and functions.

10. In Object-Relational Databases, what is a 'Table Inheritance' concept? — A way to define a table that inherits columns and constraints from another table.

11. What is a 'Collection-Member' relationship in Object Databases? — A relationship where an object contains or is part of a collection of other objects.

12. In an Object Database, what is a 'Collection'? — A group of objects of the same class.

13. What is an 'Object Cache' in Object Database systems? — A memory area that holds frequently accessed database objects for faster retrieval.

14. What is a 'Class' in an Object Database schema? — A blueprint or template defining the structure (attributes) and behavior (methods) of a set of objects.

15. Which of the following best describes a 'Composite Object' in Object Database terms? — An object that consists of other objects, forming a hierarchical structure.

16. What is a 'Complex Object' in the context of Object Databases? — An object that contains other objects or references to other objects.

17. Which of these is NOT a core concept directly inherited from OOP into Object Databases? — Relational Schema

18. What is the fundamental concept behind an Object Database? — Data is stored as objects, similar to objects in object-oriented programming.

19. What is a key advantage of Object Databases for applications dealing with version control systems or configuration management? — Natural representation and querying of object histories and relationships.

20. Which of the following is a characteristic of Object Databases that helps manage complex relationships between objects? — Direct object references or pointers

21. What is 'Identity' in the context of Object Databases, as opposed to 'Value'? — Identity is a unique, immutable OID, while Value refers to the actual data content of the object's attributes.

22. Which term describes the ability of different objects to respond to the same message (method call) in different ways? — Polymorphism

23. What is a potential disadvantage of Object Databases compared to Relational Databases? — Maturity and standardization of query languages and tools.

24. What challenge does Object Database Mapping (ODM) address? — Mapping object-oriented programming language objects to database objects.

25. Which feature of Object Databases allows for the definition of custom data types that can encapsulate both data and behavior? — User-Defined Types (UDTs) or Abstract Data Types (ADTs)

26. What is a key difference between Object Databases and Object-Relational Databases regarding their origin? — Object Databases were designed from scratch for object paradigms, while ORDBs extend relational databases with object features.

27. What does 'Persistence' mean in the context of Object Databases? — Objects can be saved and retrieved from the database even after the program terminates.

28. Which application domain benefits significantly from the ability of Object Databases to model complex, nested data structures like XML documents or JSON data? — Web Services and Data Integration

29. Which feature allows an object in an Object Database to inherit properties and behaviors from its parent class? — Inheritance

30. Which characteristic of Object-Oriented Programming (OOP) is directly mirrored in Object Databases? — Encapsulation and Inheritance

31. Which type of data is often poorly handled by traditional relational databases but well-suited for object databases? — Hierarchical or graph-like structures.

32. Which of the following is a typical application area for Object Databases? — Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM).

33. What is the primary advantage of using Object Databases for complex data types like multimedia or CAD designs? — Direct mapping of complex data structures and relationships.

34. What is a common query language extension used in ORDBs to support object-oriented features? — SQL:1999 and later standards (e.g., SQL/Object)

35. What is a primary use case for Object Databases in scientific research, such as genomics or particle physics? — Managing complex, multi-dimensional datasets and experimental data.

36. What is 'Object Versioning' in some advanced Object Database systems? — The mechanism to track and manage different revisions of an object over time.

37. What is 'Encapsulation' in Object Databases? — The bundling of data (attributes) and methods (behavior) that operate on the data within a single unit (object).

38. What is a potential performance bottleneck in Object-Relational Databases when implementing complex object hierarchies? — The overhead of object-relational mapping (ORM) and the need for multiple table joins.

39. What is 'Late Binding' in Object Databases, often associated with Polymorphism? — The resolution of method calls to the correct implementation at runtime, based on the object's actual type.

40. What is a 'Method Dispatch' mechanism in Object Databases? — The process of deciding which method implementation to execute based on the object's type.

41. What does the term 'Schema Evolution' refer to in Object Databases? — The ability to modify the structure of classes and their relationships over time without losing existing data.

42. In the context of Object Databases, what does 'Object Identity' (OID) represent? — A unique, system-generated identifier for each object, independent of its attribute values.

43. In ORDBs, how are complex data types typically handled? — They are represented as User-Defined Types (UDTs) or abstract data types.

44. What is a potential drawback of ORDBs compared to pure Object Databases when dealing with very complex object hierarchies? — They might require more complex mapping and potentially lead to performance overhead.

45. What is the main advantage of Object Databases for storing and querying recursive data structures (like organizational charts or bill-of-materials)? — They map naturally to object structures, simplifying traversal.

46. What is the role of a 'Query Optimizer' in an Object Database system? — To translate object-oriented queries into low-level data access operations and find the most efficient execution plan.

47. What is the purpose of 'Persistence Transparency' in Object Databases? — To make the distinction between in-memory objects and persistent database objects invisible to the programmer.

48. What is the primary goal of an Object Database Management System (ODBMS)? — To provide a system for creating, storing, and accessing data as objects.

Object and Object-Relational Databases - concepts and applications - One Line Questions