A. TRUE-FALSE: GROUP 2 PRACTICE EXAMPLES FOR THE REVIEW QUIZ:

Transcription

1 GROUP 2 PRACTICE EXAMPLES FOR THE REVIEW QUIZ: Review Quiz will contain very similar question as below. Some questions may even be repeated. The order of the questions are random and are not in order of importance or difficulty level. There may be few terminologies unknown to you. Read those from your text (chapter 5). All the concepts are covered in chapter 5 of your text. We will also discuss the new terminologies in the class. (the following questions are covered from your text) A. TRUE-FALSE: 1. A relation is a two-dimensional table. 2. Rows are called attributes. 3. Columns are called tuples. 4. A functional dependency is a relationship between or among attributes. 5. The known or given attribute is called the determinant in a functional dependency. 6. The relationship in a functional dependency is one-to-one (1:1). 7. If a composite attribute is a determinant, then the individual attributes also functional determine the same attribute as the composite attribute. 8. A key is a group of one or more attributes that uniquely identifies a row. 9. The selection of the attributes to use for the key is determined by the database programmers. 10. Rows in a relation must be unique. 11. A deletion anomaly occurs when deleting one entity results in deleting facts about another entity. 12. An insertion anomaly occurs when we cannot insert some data into the database without inserting another entity first. 13. Modification anomalies do not occur in tables that meet the definition of a relation. 14. Normalization is the process of splitting a relation into two or more relations. 15. Relations are classified into normal forms, based on the type of modification anomalies to which they are vulnerable. 16. A table of data that meets the minimum definition of a relation is automatically in first normal form. 17. The order of the rows in a relation is determined by the key chosen. 18. A relation is in first normal form if all of its non-key attributes are dependent on part of the key. 19. A relation is in second normal form if all of its non-key attributes are dependent on all of the key. 20. A transitive dependency occurs when one non-key attribute determines another non-key attribute. 21. A relation can be in third normal form without being in second normal form. 22. A relation often has two or more attributes or attribute collections that can be a key. 23. A relation is in Boyce-Codd normal form if every determinant is a candidate key. 24. A multivalued dependency occurs when an attribute that has multiple values depends on another attribute. 25. Fifth normal form is the highest normal form. 26. A relation can be converted into domain/key normal form using an algorithm specified by R. Fagin. 27. A relation in domain/key normal form is guaranteed to have no modification anomalies. 28. Two attributes in a relation can determine each other. 29. If attribute A determines B, but B does not determine A, the relationship among their data values is one-toone. 30. Normalized relations are sometimes de-normalized to improve performance.

2 B. MULTIPLE-CHOICE 31. A relation is analogous to a: a. file b. field c. record d. row e. column 32. A tuple is analogous to a: a. file b. row c. column d. field e. table 33. An attribute is analogous to a: a. field b. file c. row d. table e. record 34. In a relation: a. the order of the rows and the columns is significant b. the order of the rows is significant, but the order of the columns is not c. the order of the columns is significant, but the order of the rows is not d. neither the order of the rows nor the columns is significant e. the order of the rows and the columns is specified when the relation is defined 35. In a functional dependency, the determinant: a. will be paired with one value of the dependent attribute b. may be paired with one or more values of the dependent attribute c. may consist of more than one attribute d. a and c e. b and c 36. When the determinant contains two attributes: a. the first attribute determines the dependent attribute b. the second attribute determines the dependent attribute c. both attributes determine the dependent attribute d. either the first or second attribute determines the dependent attribute e. the first attribute determines the second 37. A key in a relation: a. may not functionally determine any attribute in the row b. functionally determines only one attribute in the row c. functionally determines at least one attribute in the row d. functionally determines all the attributes in the row e. functionally determines all duplicate rows 38. An anomaly in a relation is: a. an unusual data value b. a duplicate data value caused by changing the data c. an undesirable consequence of changing the data d. an error in the design

3 e. a conflict between the users' and developers' views 39. Restrictions on operations on a relation are called: a. deletion anomalies b. insertion anomalies c. modification anomalies d. domains e. referential integrity constraints 40. The normalization process generally: a. reduces the number of relations b. increases the number of relations c. reduces the number of functional dependencies d. increases the number of functional dependencies e. reduces the number of duplicate rows 41. A relation is automatically in: a. First Normal Form b. Second Normal Form c. Third Normal Form d. Boyce-Codd Normal Form e. Fourth Normal Form 42. A relation is in second normal form if all its non-key attributes are: a. dependent on part of the key b. dependent on all of the key c. independent of the key d. independent of each other e. independent of any other relation 43. A relation is in third normal form if all its non-key attributes are: a. dependent on part of the key b. dependent on all of the key c. independent of the key d. independent of each other e. independent of any other relation 44. A relation is in Boyce-Codd normal form if: a. every determinant is a candidate key b. every determinant is a primary key c. every attribute is a candidate key d. there is more than one candidate key e. there is more than one primary key 45. The primary key is: a. selected by the developers b. selected by the users c. automatically determined by the design d. determined by the DBMS e. determined by the sequence selected for the rows 46. A multivalued dependency exists when a relation has: a. at least two attributes, both of them are multivalued, and their values depend on each other b. at least two attributes, one of them is multivalued, and its value depends on the other c. at least three attributes, two of them are multivalued, and their values depend on only the third attribute d. at least three attributes, one of them is multivalued, and its value depends on the other two attributes

4 e. at least three attributes, all of them are multivalued, and their values depend on each other 47. A relation is in fourth normal form if it is in BCNF and it has no: a. transitive dependencies b. multivalued dependencies c. deletion anomalies d. insertion anomalies e. referential integrity conflicts 48. A relation is in domain/key normal form if: a. every key of the relation is a logical consequence of the definition of constraints and determinants b. every key of the relation is a logical consequence of the definition of constraints and domains c. every constraint on the relation is a logical consequence of the definition of keys and determinants d. every constraint on the relation is a logical consequence of the definition of keys and domains e. every domain of the relation is a logical consequence of the definition of keys and constraints 49. The advantage of having a relation in domain/key normal form is that: a. it takes less storage space than other normal forms b. it is easily obtained from Boyce-Codd normal form c. there is an algorithm for obtaining DK/NF d. it is obtained by enforcing referential integrity constraints e. it is guaranteed to have no modification anomalies 50. Synthesizing relations means that the developers start with a: a. relation and normalize it b. relation and determine its functional dependencies c. set of attributes and determine what relations should be formed d. set of attributes and normalize them e. set of attributes and remove any modification anomalies 51. If two attributes A and B have a one-to-one attribute relationship, it would be shown as: 52. If two attributes A and B have a many-to-one attribute relationship, it would be shown as: 53. If two attributes A and B have a many-to-many attribute relationship, it would be shown as: 54. When a relation has a key consisting of multiple attributes, you can add a new attribute to the relation: a. without any restriction b. so long as it is functionally dependent on part of the key c. so long as it is functionally dependent on all of the key

5 d. so long as it is functionally dependent on a non-key attribute e. so long as it is a candidate key 55. Relations should be normalized to the greatest extent possible except when: a. it would take too long b. performance would be adversely affected c. the database is too large d. the DBMS can't support the restrictions e. data duplication is desired C. FILL-IN BLANKS: 56. A is a two-dimensional table. 57. Rows are called. 58. Columns are called. 59. A is a relationship between or among attributes. 60. The known or given attribute in a functional dependency is called the. 61. A is a group of one or more attributes that uniquely identifies a row. 62. is the process of redefining or splitting a relation into two or more relations that have more desirable properties. 63. For some relations, changing the data can have undesirable consequences, called. 64. A occurs when deleting facts about one entity causes facts about another entity to be deleted. 65. An occurs when we can't insert facts about one entity until we insert facts about another entity. 66. require that before an attribute of a relation can be stored as an attribute in another relation, the value of the attribute must be stored in the first relation. 67. Relations can be classified into classes called, based on the types of modification anomalies to which they are vulnerable. 68. Any table of data that meets the definition of a relation is said to be in. 69. A relation is in if all its non-key attributes are dependent on the entire key. 70. A relation is in third normal form if it is in second normal form and has no. 71. Two or more attributes or attribute collections that can be a key are called. 72. The attribute or attribute collection which is used to uniquely identify each row is called the. 73. A relation is in Boyce-Codd normal form if every is a candidate key. 74. A exists when a relation has at least three attributes, two of them are multivalued, and their values depend on only the third attribute. 75. A relation is in if every constraint on the relation is a logical consequence of the definition of keys and domains. 76. If two attributes have a, they functionally determine each other. 77. If attribute A determines B, but B does not determine A, the relationship among their data values is. 78. If attribute A does not determine B and B does not determine A, the relationship among their data values is. 79. Relations are sometimes purposely left unnormalized or are normalized and then de-normalized in order to. 80. In some cases, creating is preferred to the standard normalization techniques. 81. Describe the relationship between functional dependencies, keys, and uniqueness. 82. Describe the different types of modification anomalies. 83. What is meant by a referential integrity constraint? 84. Give the requirements for a table to be in First, Second, and Third Normal forms. 85. Give the requirements for a table to be in Domain/Key Normal Form, and give the advantage and the disadvantage of the technique.