Chapter 3 Multiple Choice
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
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
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
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
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
43. The relationship is the "relational model ideal." a. 1:1 b. 1:M c. M:1 d. M:N
ANSWER: b 1:M
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
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
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
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
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
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