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90 Cards in this Set
- Front
- Back
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1) All relations are tables, but not all tables are relations. |
Answer: TRUE
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2) A relation is a three-dimensional table.
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Answer: FALSE
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3) A characteristic of a relation is that the cells of the relation hold a single value.
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Answer: TRUE
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4) A characteristic of a relation is that the rows of a relation may hold identical values.
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Answer: FALSE
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5) A relation is a table composed of columns and rows.
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Answer: TRUE
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6) In relational terms as defined by E.F. Codd, a row is called a tuple.
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Answer: TRUE
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7) In relational terms as defined by E.F. Codd, a column is called an attribute.
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Answer: TRUE
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8) The columns of a relation are sometimes called tuples.
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Answer: FALSE
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9) A tuple is a group of one or more columns that uniquely identifies a row.
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Answer: FALSE
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10) A functional dependency is a relationship between attributes such that if we know the value of one attribute, we can determine the value of the other attribute.
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Answer: TRUE
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11) If by knowing the value of A we can find the value of B, then we would say that B is functionally dependent on A.
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Answer: TRUE
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12) In functional dependencies, the attribute whose value is known or given is referred to as the determinant.
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Answer: TRUE
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13) Attribute Y is functionally dependent on attribute X if the value of attribute X determines the value of Y.
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Answer: TRUE
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14) The functional dependency noted as A → B means that the value of A can be determined from the value of B.
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Answer: FALSE
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15) In the functional dependency shown as A → B, B is the determinant.
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Answer: FALSE
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16) Functional dependencies can involve groups of attributes.
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Answer: TRUE
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17) Given the functional dependency (A, B) → C, the attributes (A, B) are referred to as a composite determinant.
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Answer: TRUE
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18) Given the functional dependency A → (B, C), then it is true that A → B and A → C.
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Answer: TRUE
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19) Given the functional dependency (A, B) → C, then it is true that A → C and B → C.
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Answer: FALSE
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20) Given the functional dependency A → B, then it is necessarily true that B → A.
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Answer: FALSE
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21) A determinant of a functional dependency may or may not be unique in a relation.
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Answer: TRUE
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22) A key is a combination of one or more columns that is used to identify particular rows in a relation.
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Answer: TRUE
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23) A row can be uniquely identified by a key.
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Answer: TRUE
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24) A combination key is a group of attributes that uniquely identifies a row.
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Answer: FALSE
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25) A key can be composed of a group of attributes taken together.
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Answer: TRUE
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26) It is possible to have a relation that does not have a key.
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Answer: FALSE
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27) A candidate key is one of a group of keys that may serve as the primary key in a relation.
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Answer: TRUE
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28) A relation can have only one candidate key.
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Answer: FALSE
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29) A primary key is a candidate key that has been selected to uniquely identify rows in a relation.
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Answer: TRUE
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30) A surrogate key is an artificial column that is added to a relation to be its primary key.
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Answer: TRUE
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31) Surrogate keys usually slow performance.
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Answer: FALSE
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32) Surrogate keys are normally not shown on forms or reports.
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Answer: TRUE
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33) A foreign key is one or more columns in one relation that also is the primary key in another table.
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Answer: TRUE
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34) A referential integrity constraint is used to make sure the values of a foreign key match a valid value of a primary key.
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Answer: TRUE
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35) A constraint that requires an instance of an entity to exist in one relation before it can be referenced in another relation is called an insertion anomaly.
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Answer: FALSE
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36) A referential integrity constraint limits the values of a foreign key.
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Answer: TRUE
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37) If a table meets the minimum definition of a relation, it has an effective or appropriate structure.
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Answer: FALSE
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38) Undesirable consequences of changing the data in a relation are called "modification anomalies."
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Answer: TRUE
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39) A deletion anomaly exists when deleting data about one entity results in the loss of data about another entity.
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Answer: TRUE
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40) Relations are classified into "normal forms" based on the types of modification anomalies that they are vulnerable to.
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Answer: TRUE
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41) Any table that meets the definition of a relation is said to be in first normal form (1NF).
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Answer: TRUE
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42) Any table that meets the definition of a relation is in 2NF.
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Answer: FALSE
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43) A relation is in 2NF if and only if it is in 1NF and all non-key attributes are determined by the entire primary key.
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Answer: TRUE
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44) A relation is in 3NF if and only if it is in 2NF and there are no non-key attributes determined by another non-key attribute.
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Answer: TRUE
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45) The condition that a non-key attribute determines another non-key attribute is known as transitive dependency.
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Answer: TRUE
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46) An attribute is considered to be a non-key attribute when it is a non-prime attribute, which means that the attribute is not contained in any candidate key.
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Answer: TRUE
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47) Candidate keys are called interlocking candidate keys when they share one or more attributes.
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Answer: FALSE
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48) A relation is in Boyce-Codd Normal Form (BCNF) if and only if it is in 3NF and every determinant is a candidate key.
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Answer: TRUE
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49) A defining requirement for Boyce-Codd Normal Form (BCNF) is that every candidate key must be a determinant.
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Answer: FALSE
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50) Every time we break up a relation during the normalization process, we may have to create a referential integrity constraint.
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Answer: TRUE
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51) The essence of normalization is taking a relation that is not in BCNF and breaking it into multiple relations such that each one is in BCNF.
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Answer: TRUE
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52) When designing or normalizing relations, each relation should have only one theme.
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Answer: TRUE
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53) A multivalued dependency exists when a determinant is matched to a set of values.
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Answer: TRUE
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54) The multivalued dependency noted as A → → B, means that the value of A determines a set of values of B.
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Answer: TRUE
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55) A relation is in 4NF when multivalued dependencies are isolated in their own relation.
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Answer: TRUE
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56) A relation is in 4NF if it is in BCNF and it has no multivalued dependencies.
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Answer: TRUE
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57) Domain/key normal form requires that every constraint be a logical consequence of the definition of domains and keys.
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Answer: TRUE
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58) A relation that is in domain/key normal form is assured to be free from all anomalies.
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Answer: TRUE
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59) A relation ________.
A) has rows containing data about an entity B) has columns containing data about attributes of the entity C) has cells that hold only a single value D) has no two identical rows E) All of the above. |
Answer: E
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60) In a relation ________.
A) entities in a column vary as to kind B) the order of the columns is important C) the order of the rows is unimportant D) more than one column can use the same name E) All of the above. |
Answer: C
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61) A relation is also known as a(n) ________.
A) table B) tuple C) relationship D) attribute E) field |
Answer: A
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62) A tuple is also known as a(n) ________.
A) table B) relation C) row D) field E) file |
Answer: C
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63) An attribute is also known as a(n) ________.
A) table B) relation C) row D) field E) file |
Answer: D
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64) Saying that two entities are functionally dependent means that ________.
A) the entities are always connected by a mathematical equation B) for one of the entities, if we are given the value of that entity, we can determine the value of one other entity C) for both of the entities, if we are given the value of one entity, we can determine the value of the other entity D) the functional dependency will have to be removed through normalization E) All of the above. |
Answer: B
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65) Given the functional dependency A → (B, C), A is a(n) ________.
A) independent variable B) dependent variable C) determinant D) composite determinant E) C and D |
Answer: C
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66) Given the functional dependency (A, B) → C, (A, B) is a(n) ________.
A) independent variable B) dependent variable C) determinant D) composite determinant E) C and D |
Answer: E
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67) Given the functional dependency (A, B) → C, then ________.
A) A → B B) A → C C) B → A D) B → C E) None of the above is correct. |
Answer: E
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68) Which of the following is true about the functional dependency A → (X, Y)?
A) X is functionally dependent on A. B) A determines Y. C) A is a determinant. D) X and Y are functionally dependent on A. E) All of the above. |
Answer: E
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69) Which of the following is true about the functional dependency (A, B) → (C, D)?
A) A is the determinant of C. B) A and B together are determined by C and D together. C) A and B together determine D. D) C and D together determine A. E) A determines B. |
Answer: C
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70) The only reason(s) for having relations is to ________.
A) store instances of functional dependencies B) store equation components C) store equation results D) B and C E) A, B, and C |
Answer: A
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71) A combination of one or more columns used to identify particular rows in a relation is a ________.
A) record B) field C) key D) tuple E) dependency |
Answer: C
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72) A combination of two or more columns used to identify particular rows in a relation is a ________.
A) record B) field C) composite key D) foreign key E) surrogate key |
Answer: C
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73) A determinant that determines all the other columns in a relation is a ________.
A) record B) field C) foreign key D) candidate key E) surrogate key |
Answer: D
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74) When designing a database, one of the candidate keys in a relation is selected as the ________.
A) composite key B) primary key C) foreign key D) surrogate key E) dependency |
Answer: B
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75) An artificial column added to a relation to serve as the primary key is a ________.
A) composite key B) candidate key C) foreign key D) surrogate key E) dependency |
Answer: D
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76) A key consisting of one or more columns that is a primary key in another relation is a ________.
A) composite key B) candidate key C) foreign key D) surrogate key E) dependency |
Answer: C
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77) Referential integrity constraints are used to limit the possible values of a ________.
A) composite key B) candidate key C) foreign key D) surrogate key E) dependency |
Answer: C
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78) A ________ is used to limit the possible values of a(n) foreign key.
A) composite key B) surrogate key C) functional dependency D) referential integrity constraint E) normal form |
Answer: D
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79) Normalization is a process used to deal with which of the following modification anomalies?
A) Insertion anomaly B) Update anomaly C) Deletion anomaly D) A and B E) A, B, and C |
Answer: E
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80) If the removal of facts about one entity results in the unintentional loss of data about another entity, this is referred to as a(n) ________.
A) normalization anomaly B) insertion anomaly C) update anomaly D) deletion anomaly E) removal anomaly |
Answer: D
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81) Suppose that you need to update one value of the column SalesCost in a relation. The way the relation is constructed, this value actually needs to be changed in three different rows. However, you only change the value in two of the rows. You have just created an a(n) ________.
A) normalization anomaly B) insertion anomaly C) update anomaly D) deletion anomaly E) removal anomaly |
Answer: C
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82) A table that meets the definition of a relation is in ________.
A) First Normal Form B) Second Normal Form C) Third Normal Form D) Boyce-Codd Normal Form E) Fourth Normal Form |
Answer: A
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83) A relation is in second normal form (2NF) if and only if it is in 1NF and ________.
A) all non-key attributes are determined by the entire primary key B) there are no non-key attributes determined by another non-key attribute C) every attribute is a candidate key D) every candidate key is a determinant E) every determinant is a candidate key |
Answer: A
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84) A relation is in third normal form (3NF) if and only if it is in 2NF and ________.
A) all non-key attributes are determined by the entire primary key B) there are no non-key attributes determined by another non-key attribute C) every attribute is a candidate key D) every candidate key is a determinant E) every determinant is a candidate key |
Answer: B
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85) A relation is in Boyce-Codd normal form (BCNF) if and only if it is in 3NF and ________.
A) all non-key attributes are determined by the entire primary key B) there are no non-key attributes determined by another non-key attribute C) every attribute is a candidate key D) every candidate key is a determinant E) every determinant is a candidate key |
Answer: E
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86) If a table is designed so that every determinant is a candidate key, then that relation is in ________.
A) First Normal Form B) Second Normal Form C) Third Normal Form D) Boyce-Codd Normal Form E) Fourth Normal Form |
Answer: D
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87) If a relation is in BCNF, and each multivalued dependency has been moved to a relation of its own, then the first relation is in ________.
A) First Normal Form B) Second Normal Form C) Third Normal Form D) Boyce-Codd Normal Form E) Fourth Normal Form |
Answer: E
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88) A relation is in fourth normal form if it is in BCNF and it has no ________.
A) transitive dependencies B) multivalued dependencies C) partial dependencies D) deletion dependencies E) referential integrity conflicts |
Answer: B
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89) 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 |
Answer: D
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90) In general, each relation should have ________.
A) one and only one theme B) one or more themes C) exactly two themes D) one or two themes E) exactly three themes |
Answer: A |
