Test your basic knowledge |

Data Modeling

Subject : it-skills
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. A talbe is in 4NF if it is 3NF and has no ________.






2. A table that has all key attributes defined - has no repeating groups - and all its attributes are dependent on the primary key - is said to be in ____.






3. If database tables are treated as though they were files in a file system - the ___ never has a chance to demonstrate its superior data-handling capabilities.






4. The associative entity is also known as a ___ entity.






5. A ___ derives its name from the fact that a group of multiple entries of the same type can exist for any single key attribute occurrence.






6. The set of possible values for an attribute is a ____.






7. An attribute that is part of a key is known as a ____ attribute.






8. ________ cannot be further subdivided.






9. Dependencies can be identified with the help of a dependency _____.






10. In order to meet performance requirements - you may have to denormalize portions of the ________.






11. Complex ____ requirements may dictate data transformations - and they may expand the number of entities and attributes withing the design.






12. Any attribute whose value determines other values within a row is called ____.






13. Improving ___ leads to more flexible queries.






14. If a table has multiple candidate keys and one of those candidate keys is a composite key - the table can have ___ based on this composite candidate key - even when the primary key chosen is a single attribute.






15. In a ___ diagram - the arrows above the attribute indicate all desirable dependencies.






16. Need not be stored physically in the data base.






17. A ____ exists when there are functional dependencies such that Y is functionally dependent on X and Z is functionally dependent on Y - and X is the primary key.






18. When a nonkey attribute is the determinate of a key attribute the table is in 3NF but not ____.






19. A table where every determinant is a candidate key is said to be in ____.






20. BCNF can be violated only if the table contains more than one ___ key.






21. In order to meet ___ requirements - you may have to denormalize some portion of the database.






22. An example of denormalization is using a ___ denormalized table to hold report data. This is required when creating a tabular report in which the columns represent data that is stored in the table as rows.






23. From a system functionality point of view - ___ attribute values can be calculated when they are needed to write reports or invoices.






24. ______________database tables often lead to various data redundancy disasters in production databases.






25. Dependencies based on only a part of a composite primary key are called ___ dependencies.






26. A ___ attribute is one that cannot be subdivided.






27. Data redundancies occur from ____ of data on every row entry.






28. The word "entity" in the ER model corresponds to a _______.






29. A table where all attributes are dependent on the primary key are independent of each other - and no row contains two or more multivalued facts about an entity - is said to be in ____.






30. The ___ refers to a specific table row as an entity instance.






31. The Crow's foot symbol with two parallel lines indicates ___ cardinality.






32. A ___ relationship exists when an association is maintained within a single entity.






33. If you have three different transitive dependencies - ___ different determinants exist.






34. A table is in BCNF if every determinant in the table is a ____________.






35. The price paid for increased performance through denormalization is a larger amount of ____.






36. A ___________ must not contain a repeating group .






37. Depicts all dependencies found within a given table structure is known as a ______.






38. _______ databases reflect the ever-growing demand for greater scope and depth in the data on which decision support systems increasingly rely.






39. A ___ identifier is composed of more than one attribute.






40. An ERM is not dependent on the ____________.






41. According to naming conventions described in Chapter 2 - ___ would be the best name for a column representing the charges per hour in a table named JOB.






42. For most business transactional databases - we should normalize relations into ____.






43. Most designers consider the BCNF as a special case of the ____.






44. A table that is in 2NF and contains no transitive dependencies is said to be in ___.






45. Data redundancy produces ____.






46. A ___ entity has a primary key that is partially or totally derived from the parent entity in the relationship.






47. Another word for existence-independent is ____.






48. In a real-world environment - changing granularity requirements might dictate changes in primary key selection - and those changes might ultimately require the use of ____ keys.






49. A ____ relationship exists when three entities are associated.






50. If an employee within an EMPLOYEE entity has a relationship with itself - that relationship is known as a ____ relationship.