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






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






3. View the data as part of a table or collection of tables in which all key values must be identified.






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






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






6. Refers to the level of detail represented by the values stored in a table's row






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






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






9. 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.






10. A _____ entity is composed of the primary keys of each of the entities to be connected.






11. Improving ___ leads to more flexible queries.






12. __________ is a process to help reduce the likelihood of data anomalies.






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






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






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






16. A ___________ must not contain a repeating group .






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






18. 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.






19. From a structural point of view - ______ is better than 1NF






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






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






22. 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.






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






24. Data redundancy produces ____.






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






26. A ______ attribute can have only one value.






27. 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.






28. ________ cannot be further subdivided.






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






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






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






32. 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.






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






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






35. 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.






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






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






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






39. ____ yields better performance.






40. 1NF - 2NF - and 3NF are _____.






41. A ___ relationship exists when two entities are associated.






42. The existence of a(n) ___ relationship indicated that the minimum cardinality is at least 1 for the mandatory entity.






43. In the ERD - Cardinality is indicated using the ___ notation.






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






45. A talbe is in 4NF if it is 3NF and has no ________.






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






47. THE MOST LIKELY DATA TYPE FOR A SURROGATE KEY IS ____.






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






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






50. 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.