Chapter 3 Multiple Choice

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34. returns only the attributes requested, in the order in which they are requested. a. PROJECT b. SELECT c. UNION d. DIFFERENCE

ANSWER: a. PROJECT

48. When you define a table's primary key, the DBMS automatically creates a(n) index on the primary key column(s) you declared. a. key b. composite c. unique d. primary

ANSWER: c. unique

50. According to Codd's rule of relational database, "If the system supports lowlevel access to the data, users must not be allowed to bypass the integrity rules of the database." a. nonsubversion b. rule zero c. view updating d. information

ANSWER: a. nonsubversion

25. A is any key that uniquely identifies each row. a. superkey b. special key c. foreign key d. candidate key

ANSWER: a. superkey

31. The constraint can be placed on a column to ensure that every row in the table has a value for that column. a. UNIQUE b. NOT NULL c. VALUE d. EMPTY

ANSWER: b. NOT NULL

26. A key can be described as a minimal superkey, a superkey without any unnecessary attributes. a. secondary b. candidate c. primary d. foreign

ANSWER: b. candidate

21. logic, used extensively in mathematics, provides a framework in which an assertion (statement of fact) can be verified as either true or false. a. Predicate b. Database c. Relational d. Index

ANSWER: a. Predicate

46. Another name for a composite entity is a(n) entity. a. bridge b. linked c. directive d. associative

ANSWER: a. bridge

37. are especially useful when you are trying to determine what values in related tables cause referential integrity problems. a. Inner joins b. Outer joins c. Equijoins d. Theta joins

ANSWER: b. Outer joins

44. The relationship should be rare in any relational database design. a. 1:1 b. 1:M c. M:1 d. M:N

ANSWER: a

30. The CUSTOMER table's primary key is CUS_CODE. The CUSTOMER primary key column has no null entries, and all entries are unique. This is an example of integrity. a. entity b. referential c. relational d. null

ANSWER: a. entity

43. The relationship is the "relational model ideal." a. 1:1 b. 1:M c. M:1 d. M:N

ANSWER: b 1:M

41. In a database context, the word indicates the use of the same attribute name to label different attributes. a. redundancy b. homonym c. duplicate d. synonym

ANSWER: b. homonym

38. A(n) only returns matched records from the tables that are being joined. a. outer join b. inner join c. equijoin d. theta join

ANSWER: b. inner join

24. In the relational model, are important because they are used to ensure that each row in a table is uniquely identifiable. a. relations b. keys c. indexes d. logical structures

ANSWER: b. keys

49. According to Codd's rule of relational database, "Application programs and ad hoc facilities are logically unaffected when changes are made to the table structures that preserve the original table values (changing order of columns or inserting columns)." a. nonsubversion b. logical data independence c. comprehensive data sublanguage d. integrity independence

ANSWER: b. logical data independence

35. When two or more tables share the same number of columns, and when their corresponding columns share the same or compatible domains, they are said to be . a. intersect-compatible b. union-compatible c. difference-compatible d. select-compatible

ANSWER: b. union-compatible

23. Date attributes contain calendar dates stored in a special format known as the date format. a. Epoch b. calendar c. Julian d. logical

ANSWER: c. Julian

45. relationships can be implemented by creating a new entity in 1:M relationships with the original entities. a. 1:N b. M:1 c. M:N d. 1:1

ANSWER: c. M:N

42. In a database context, a(n) indicates the use of different names to describe the same attribute. a. entity b. duplicate c. synonym d. homonym

ANSWER: c. synonym

32. To be considered minimally relational, the DBMS must support the key relational operators , PROJECT, and JOIN. a. INTERSECT b. UNION c. DIFFERENCE d. SELECT

ANSWER: d. SELECT

33. , also known as RESTRICT, yields values for all rows found in a table that satisfy a given condition. a. INTERSECT b. UNION c. DIFFERENCE d. SELECT

ANSWER: d. SELECT

27. A is the primary key of one table that has been placed into another table to create a common attribute. a. superkey b. composite primary key c. candidate key d. foreign key

ANSWER: d. foreign key

47. A(n) is an orderly arrangement used to logically access rows in a table. a. primary rule b. superkey c. relationship d. index

ANSWER: d. index

36. A(n) join links tables by selecting only the rows with common values in their common attribute(s). a. attribute b. unique c. foreign d. natural

ANSWER: d. natural

29. A key is defined as a key that is used strictly for data retrieval purposes. a. lookup b. foreign c. candidate d. secondary

ANSWER: d. secondary

40. The is actually a system-created database whose tables store the user/designer-created database characteristics and contents. a. database tuple b. systematic database c. unique index d. system catalog

ANSWER: d. system catalog

28. Referential dictates that the foreign key must contain values that match the primary key in the related table, or must contain null. a. integrity b. uniqueness c. model d. attribute

ANSWER: a. integrity

22. Each table represents an attribute. a. column b. row c. dimension d. value

ANSWER: a. column

39. A contains at least all of the attribute names and characteristics for each table in the system. a. data dictionary b. relational schema c. logical schema d. database

ANSWER: a. data dictionary


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