MIS EXAM 2 4,5,6

Each attribute of an entity becomes a(n) ________ of a table. A) column B) primary key C) foreign key D) alternate key

A

In many-to-many relationships between strong entities in a relational database design, which of the following is not true? A) The intersection table is ID-dependent on one of the parents B) The intersection table is ID-dependent on both of the parents C) The relationships from the intersection table to the parent tables are identifying relationships D) The maximum cardinality to the intersection table is always N

A

The identifier of the entity becomes the ________ of the corresponding table. A) primary key B) foreign key C) supertype D) subtype

A

When representing a one-to-many relationship in a relational database design, ________. A) the parent is always on the one side of the "one-to-many" relationship B) the child is always on the one side of the "one-to-many" relationship C) either parent or child can be on the one side of the "one-to-many" relationship, and the choice is arbitrary D) either parent or child can be on the one side of the "one-to-many" relationship, and special criteria indicate which table should be on the one side

A

When transforming an E-R data model into a relational database design, the key of the parent entity should be placed as part of the primary key into the child entity ________. A) when the child entity is ID-dependent B) when the child entity is non-ID-dependent C) when the child entity has a 1:1 relationship with the parent entity D) when the child entity has a 1:N relationship with the parent entity

A

When transforming an ID-dependent E-R data model relationship into a relational database design, the referential integrity constraints should allow ________. A) parent updates to cascade B) child updates to cascade C) child deletes to cascade D) Both A and B are correct

A

Which of the following is not true for an ideal primary key? A) a composite of several long attributes B) numeric C) fixed D) short

A

31) When you are given a set of tables and asked to create a database to store their data, the first step is to ________. A) assess the existing tables' structure and content B) design the database structure C) create one or more new tables D) move the data into the new database E) design the applications that will use the database

A Diff: 1 Page Ref: 128-129 Fig 4-1

52) A table designed to store PhoneNumber01, PhoneNumber02 and PhoneNumber03 contains ________. A) the multivalued, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem E) None of the above is correct.

A Diff: 1 Page Ref: 135

42) Entities of a given type are grouped into a(n) ________. A) entity class B) entity relationship C) entity instance D) entity attribute E) None of the above.

A Diff: 1 Page Ref: 145

46) A classic example of unneeded normalization is when we are dealing with ________. A) ZIP codes B) sales orders and line items C) association patterns D) multivalued dependencies E) general purpose remarks columns

A Diff: 2 Page Ref: 131

53) A form of multivalued dependency is found in ________. A) the multivalued, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem E) None of the above is correct.

A Diff: 2 Page Ref: 136

49) Maximum cardinality refers to ________. A) the most instances of one entity class that can be involved in a relationship instance with another entity class B) the minimum number of entity classes involved in a relationship C) whether or not an instance of one entity class is required to be related to an instance of another entity class D) whether or not an entity is a weak entity E) None of the above.

A Diff: 2 Page Ref: 149

41) The advantages of normalization include ________. A) the elimination of modification anomalies B) the elimination of duplicated data C) more complex SQL for multitable subqueries and joins D) A and B E) A, B and C

A Diff: 3 Page Ref: 129 Fig 4-2

48) For a relationship to be considered a binary relationship it must satisfy which of the following conditions? A) It must involve exactly two entity classes. B) It must have a maximum cardinality of 1:1. C) It must have a maximum cardinality of 1:N. D) A and B E) A and C

A Diff: 3 Page Ref: 147-149

67) To represent a multivalued attribute in an E-R model, ________. A) create a new ID-dependent entity with a 1:N relationship B) create a new weak, but not ID-dependent entity with a 1:N relationship C) create a new strong entity with a 1:1 relationship D) create a new ID-dependent entity with a 1:1 relationship E) create a new weak, but not ID-dependent entity with a 1:1 relationship

A Diff: 3 Page Ref: 164-165

68) To represent an archetype/instance pattern in an E-R model, ________. A) create a new ID-dependent entity with a 1:N relationship B) create a new weak, but not ID-dependent entity with a 1:N relationship C) create a new strong entity with a 1:1 relationship D) create a new ID-dependent entity with a 1:1 relationship E) create a new weak, but not ID-dependent entity with a 1:1 relationship

A Diff: 3 Page Ref: 166-168

What is an association relationship and how does it differ from an N:M relationship?

An association relationship is very similar to an N:M relationship except that the intersection table has attributes of its own. This means that in addition to the foreign key fields linking to the two strong entities, there is at least one additional field in what would otherwise be called the intersection table but is now an association table. For example, intersection table ENROLLMENT for STUDENT and CLASS showing student enrollment in each class would normally have two columns: StudentID and ClassID. However, we can turn this intersection table into an association table by adding the column Grade, which records each student's grade in each class.

In a relational database design, all relationships are expressed by ________. A) creating a primary key B) creating a foreign key C) creating a supertype D) creating a subtype

B

The binary constraint MUST COVER indicates that ________. A) a specific binary relationship must be included in a ternary relationship B) a binary relationship includes a set of value combinations that must all occur in a ternary relationship C) a table includes values that must occur in a binary relationship D) a table includes values that must occur in a ternary relationship

B

To represent a one-to-many relationship in a relational database design, ________. A) the key of the child is placed as a foreign key into the parent B) the key of the parent is placed as a foreign key into the child C) an intersection table must be created D) the key of the table on the "many" side is placed in the table on the "one" side

B

When representing a 1:1 relationship in a relational database design, ________. A) the key of each table must be placed as foreign keys into the other B) the key of either table may be placed as a foreign key into the other C) the key of both tables must be the same D) the intersection table gets the key from both relations

B

Which of the following is not true about representing subtypes in a relational database design? A) One table is created for the supertype and one for each subtype. B) All of the attributes of the supertype are added to the subtype relations. C) The key of the supertype is made the key of the subtypes. D) An instance of the supertype may be related to one instance each of several subtypes.

B

Which of the following is not true of MUST constraint? A) It may be needed in ternary relationships to enforce special business rules. B) It can be expressed directly in a relational model. C) It must be enforced by program code. D) It requires that one entity be combined with another entity.

B

37) The SQL function COUNT ________. A) counts the number of columns in a table B) counts the number of rows in a table C) counts the number of tables in a database D) A and C E) B and C

B Diff: 1 Page Ref: 128

39) The SQL keyword TOP ________. A) limits the number of columns retrieved from a table B) limits the number of rows retrieved from a table C) limits the number of tables retrieved from a database D) A and C E) B and C

B Diff: 1 Page Ref: 128

49) For a number of reasons, ________ is not often an advantage for a read-only database. A) updating B) normalization C) denormalization D) A and B E) B and C

B Diff: 1 Page Ref: 132

55) You are creating a PRODUCT table using existing data from multiple sources. Examining the data, you find that you have "large red hat", "large hat, red", "red hat large" and "hat, large, red." This is an example of ________. A) the multivalue, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem E) None of the above is correct.

B Diff: 1 Page Ref: 136-137

57) A missing value is called a(n) ________. A) empty value B) null value C) missing value D) Any of A, B or C can be used. E) None of the above is correct.

B Diff: 1 Page Ref: 137-138

61) An entity that holds specialized attributes that distinguish it from one or more other similar entities is a(n) ________. A) supertype B) subtype C) discriminator D) A and C E) B and C

B Diff: 1 Page Ref: 156-157

38) To limit the number of rows retrieved from a table, use the SQL construct ________. A) SELECT * B) SELECT TOP n * C) SELECT COUNT(TOP n) D) SELECT COUNT(*) E) SELECT COUNT *

B Diff: 2 Page Ref: 128

54) When a table is created using existing data from multiple sources, you are likely to find that the different sources code data in slightly different ways. This is an example of ________. A) the multivalued, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem E) None of the above is correct.

B Diff: 2 Page Ref: 136-137

50) You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above, and are asked to draw the relationship between them. If a given customer can place only one order and a given order can be placed by at most one customer, which of the following should be indicated in the relationship symbol between the two entities? A) 0:1 B) 1:1 C) 1:N D) N:1 E) N:M

B Diff: 2 Page Ref: 149-150

60) An entity whose existence depends on the presence of another entity, but whose identifier does not include the identifier of the other entity is a(n) ________. A) strong entity B) weak entity C) ID-dependent entity D) A and C E) B and C

B Diff: 2 Page Ref: 154-156

65) Supertype/subtype entities are said to have a(n) ________ relationship. A) HAS-A B) IS-A C) recursive D) redundant E) multivalue

B Diff: 2 Page Ref: 157

40) You have been given two tables, CUSTOMER and SALE. You want to check the referential integrity constraint: SALE.CustomerNumber must exist in CUSTOMER.CustomerNumber You run the following SQL query: SELECT CustomerNumber FROM SALE WHERE CustomerNumber NOT IN (SELECT CustomerNumber FROM SALE, CUSTOMER WHERE SALE.CustomerNumber = CUSTOMER.CustomerNumber); What is shown in the results of this query? A) All values of CustomerNumber that match the constraint. B) All values of CustomerNumber that violate the constraint. C) All values of CustomerNumber where SALE.CustomerNumber = CUSTOMER.CustomerNumber. D) A and C E) B and C

B Diff: 3 Page Ref: 128

43) The presence of one or more foreign keys in a relation prevents ________. A) the elimination of modification anomalies B) the elimination of duplicated data C) more complex SQL for multitable subqueries and joins D) A and B E) A, B and C

B Diff: 3 Page Ref: 129

73) A defining requirement for ________ is that every determinant must be a candidate key.

BCNF Diff: 2 Page Ref: 130

What are MUST NOT and MUST COVER constraints?

Both MUST NOT and MUST COVER constraints occur when working with three tables in a ternary relationship. When a MUST NOT constraint occurs, it indicates that one binary relationship of two of the tables contains combinations of values that are not allowed to occur in the ternary relationship. When a MUST COVER constraint occurs, it indicates that one binary relationship of two of the tables contains combinations of values that must all appear in the ternary relationship.

A referential integrity constraint policy that insures that foreign key values in a table are correctly maintained when there is a change to the primary key value in the parent table is called ________. A) incremental updates B) incremental deletes C) cascading updates D) cascading deletes

C

A surrogate key should be considered when ________. A) A relationship is N:M B) A composite key is required C) The key contains a lengthy text field D) The key contains a number

C

In many-to-many relationships in a relational database design, ________. A) the key of the child is placed as a foreign key into the parent B) the key of the parent is placed as a foreign key into the child C) the keys of both tables are placed in a third table D) the keys of both entity tables are placed in each other

C

In relational database design, ID-dependent entities are not used to ________. A) represent N:M relationships B) handle associative relationships C) represent relationships where the child identifier does not include the key of the parent D) handle archetype/instance relationships

C

The first step in transforming an extended E-R model into a relational database design is to ________. A) create a table for each relationship B) evaluate the entities against the normalization criteria C) create a table for each entity D) remove any recursive relationships

C

Which of the following is not true about a NULL attribute? A) On insertion, entering the data for that field is optional. B) It is an important property of an attribute. C) It must have a default value specified. D) A primary key can't be NULL.

C

Which of the following is not true about surrogate keys? A) They are identifiers that are supplied by the system, not the users. B) They have no meaning to the users. C) They are non-unique within a table. D) They can be problematic when combining databases.

C

42) The disadvantages of normalization include ________. A) the elimination of modification anomalies B) the elimination of duplicated data C) more complex SQL for multitable subqueries and joins D) A and B E) A, B and C

C Diff: 1 Page Ref: 129 Fig 4-2

43) The occurrence of a particular entity is called a(n) ________. A) entity class B) entity relationship C) entity instance D) entity attribute E) None of the above.

C Diff: 1 Page Ref: 145

47) A composite attribute is an attribute that ________. A) is multivalued B) describes a characteristic of the relationship C) consists of a group of attributes D) is calculated at run-time E) is an identifier

C Diff: 1 Page Ref: 147

63) An attribute that determines which subtype should be used is a(n) ________. A) supertype B) subtype C) discriminator D) A and C E) B and C

C Diff: 1 Page Ref: 156-157

69) When an entity has a relationship to itself, we have a(n) ________. A) supertype/subtype relationship B) archetype/instance relationship C) recursive relationship D) A or C E) B or C

C Diff: 1 Page Ref: 172

33) The second step in assessing table structure includes ________. A) counting rows B) examining columns C) examining data values D) A and B E) B and C

C Diff: 2 Page Ref: 128-129 Fig 4-1

50) ________ is the process of joining two or more tables and storing the result as a single table. A) Querying B) Normalization C) Denormalization D) A and B E) B and C

C Diff: 2 Page Ref: 132

56) When a table is created using existing data from multiple sources, you are likely to find that some data values have never been provided. This is an example of ________. A) the multivalued, multicolumn problem B) the inconsistent values problem C) the missing values problem D) the general-purpose remarks column problem E) None of the above is correct.

C Diff: 2 Page Ref: 137-138

59) To check for null values in a column in a table, use the SQL phrase ________. A) IS B) IS NOT C) IS NULL D) COUNT(IS NOT) E) COUNT(IS NULL)

C Diff: 2 Page Ref: 137-138

60) The SQL keyword IS NULL can be used to ________. A) count the number of columns in a table B) count the number of rows in a table C) count the number of null values in a column D) A and C E) B and C

C Diff: 2 Page Ref: 137-138

41) Which of the following is not a key element of an E-R model? A) Identifiers B) Entities C) Objects D) Attributes E) Relationships

C Diff: 2 Page Ref: 145-149

53) Minimum cardinality refers to ________. A) the most instances of one entity class that can be involved in a relationship with one instance of another entity class B) the minimum number of entity classes involved in a relationship C) whether or not an instance of one entity class is required to be related to an instance of another entity class D) whether or not an entity is a weak entity E) None of the above.

C Diff: 2 Page Ref: 150

56) A circle across the relationship line near an entity indicates ________. A) a maximum cardinality of "zero" B) a maximum cardinality of "one" C) a minimum cardinality of "optional" D) a minimum cardinality of "required" E) None of the above.

C Diff: 2 Page Ref: 150-151

57) You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above. What does the symbol next to the ORDER entity indicate? A) A maximum cardinality of "zero" B) A maximum cardinality of "one" C) A minimum cardinality of "optional" D) A minimum cardinality of "required" E) None of the above.

C Diff: 2 Page Ref: 150-151

63) To count the number of rows in a table, use the SQL construct ________.

COUNT(*) Diff: 2 Page Ref: 128

A referential integrity constraint policy that guarantees that a row in a parent table always has a required entry in a child table ________. A) is known as a minimum cardinality enforcement action B) needs to be documented by the database development team C) is enforced in most DBMS products D) Both A and B are correct

D

A referential integrity constraint policy that insures that all rows containing a particular foreign key value in a table are eliminated from the table when the row containing the corresponding primary key value in a parent table is eliminated from the database is called ________. A) incremental updates B) incremental deletes C) cascading updates D) cascading deletes

D

For the M-O (parent mandatory, child optional) case, what action(s) should be taken to ensure minimum cardinality is maintained? A) Define referential integrity constraint from child to parent B) Make foreign key NOT NULL C) Will require trigger or other application code D) Both A and B are correct

D

In a supertype-subtype structure, discriminator attributes ________. A) are easily represented in a relational design B) cannot be represented in a relational design C) require application logic to determine which subtypes correspond to a specific supertype instance D) Both B and C are correct

D

Many-to-many relationships are represented by ________. A) two tables with an M:N relationship B) two tables with a 1:N relationship C) an intersection table which has M:N relationships with the two tables D) an intersection table which has 1:N relationships with the two tables

D

The binary constraint MUST NOT indicates that ________. A) a specific binary relationship must not be included in a ternary relationship B) a table includes values that must not occur in a binary relationship C) a table includes values that must not occur in a ternary relationship D) a binary relationship includes value combinations that must not occur in a ternary relationship

D

When transforming an ID-dependent E-R data model relationship into a relational database design and the parent entity has a surrogate primary key and the child entity has a data identifier, then the primary key of the child table should be ________. A) the parent's surrogate key + the child's data key B) the parent's surrogate key + a surrogate key in the child C) either A or B will work, but method A is preferable D) either A or B will work, but method B is preferable

D

Which of the following is not a step in the database design process? A) Create tables and columns from entities and attributes B) Select primary keys C) Represent relationships D) Create constraints and triggers

D

Which of the following is not true about N:M recursive relationships? A) Both foreign keys in the intersection table refer to the same table. B) Since it is a recursive relationship, an intersection table is not needed. C) The foreign keys in the intersection table can't refer to the same attribute in the parent table. D) Both B and C are correct.

D

Which of the following is not true of recursive relationships? A) When the recursive relationship is M:N, an intersection table is created. B) The rows of a single table can play two different roles. C) Recursive relationships can be 1:1, 1:N, or M:N relationships. D) When the relationship is 1:N, a new table must be defined to represent the relationship.

D

44) The characteristics of a thing are described by its ________. A) identifiers B) entities C) objects D) attributes E) relationships

D Diff: 1 Page Ref: 146

46) An identifier may be ________. A) composite B) a single attribute C) a relationship D) A and B E) A, B and C

D Diff: 1 Page Ref: 146-147

64) Discriminators can be ________. A) exclusive only B) inclusive only C) decisive only D) A or B E) B or C

D Diff: 1 Page Ref: 156-157

32) The first step in assessing table structure includes ________. A) counting rows B) examining columns C) examining data values D) A and B E) B and C

D Diff: 2 Page Ref: 128-129 Fig 4-1

44) Anomalies caused by functional dependencies can be eliminated by putting tables into ________. A) 1NF B) 2NF C) 3NF D) BCNF E) 4NF

D Diff: 2 Page Ref: 129

45) The defining characteristic of BCNF is that a table is in BCNF if ________. A) all rows are unique B) all columns are consistent C) the primary key is a candidate key D) all determinants are candidate keys E) all candidate keys are determinants

D Diff: 2 Page Ref: 130

47) Unlike the anomalies from functional dependencies, the anomalies from ________ are so serious that they should always be eliminated. A) ZIP codes B) sales orders and line items C) association patterns D) multivalued dependencies E) general purpose remarks columns

D Diff: 2 Page Ref: 132

58) A null value can indicate which of the following conditions? A) The value is inappropriate. B) The value is appropriate but unknown. C) The value is appropriate and known, but not entered into the database. D) All of A, B or C are correct. E) None of the above is correct.

D Diff: 2 Page Ref: 137-138

45) Attributes may be ________. A) composite B) element C) multivalued D) A and C E) B and C

D Diff: 2 Page Ref: 146 and 150-151

54) In a minimum cardinality, minimums are generally stated as ________. A) 0 B) 1 C) N D) A or B E) A, B or C

D Diff: 2 Page Ref: 150-151

55) A hash mark across the relationship line near an entity indicates ________. A) a maximum cardinality of "zero" B) a maximum cardinality of "one" C) a minimum cardinality of "optional" D) a minimum cardinality of "required" E) None of the above.

D Diff: 2 Page Ref: 150-151

58) You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above. What does the symbol next to the CUSTOMER entity indicate? A) A maximum cardinality of "zero" B) A maximum cardinality of "one" C) A minimum cardinality of "optional" D) A minimum cardinality of "required" E) None of the above.

D Diff: 2 Page Ref: 150-151

36) To count the number of rows in a table, use the SQL construct ________. A) SELECT * B) SELECT TOP n * C) SELECT COUNT(TOP n) D) SELECT COUNT(*) E) SELECT COUNT *

D Diff: 3 Page Ref: 128

51) You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above, and are asked to draw the relationship between them. If a given customer can place many orders and a given order can be placed by at most one customer, which of the following should be indicated in the relationship symbol between the two entities? A) 0:1 B) 1:1 C) 1:N D) N:1 E) N:M

D Diff: 3 Page Ref: 149-150

66) To represent an association pattern in an E-R model, ________. A) create a new ID-dependent entity with a 1:1 relationship to one other entity B) create a new weak, but not ID-dependent entity with a 1:1 relationship to one other entity C) create a new strong entity with a 1:1 relationship to one other entity D) create a new ID-dependent entity with a 1:N relationship to one of two parent entities E) create a new weak, but not ID-dependent entity with a 1:N relationship to one of two parent entities

D Diff: 3 Page Ref: 162-164

81) ________ is the process of joining previously normalized tables back together.

Denormalization Diff: 1 Page Ref: 132-133

82) ________ reduces the complexity of the SQL statements needed in an application to read required data.

Denormalization Diff: 2 Page Ref: 132-133

48) Read-only databases are used for ________. A) updating B) querying C) reporting D) A and B E) B and C

E Diff: 1 Page Ref: 132

70) Recursive relationships can have which of the following maximum cardinalities? A) 1:1 B) 1:N C) N:M D) A or B E) A, B or C

E Diff: 1 Page Ref: 172-174

34) During the second step of the assessing table structure, you are trying to determine ________. A) multivalued dependencies B) functional dependencies C) foreign keys D) A and B E) A, B and C

E Diff: 2 Page Ref: 128-12 Fig 4-1

35) During the second step of the assessing table structure, you are trying to determine ________. A) primary keys B) candidate keys C) foreign keys D) A and B E) A, B and C

E Diff: 2 Page Ref: 128-129 Fig 4-1

52) You are given an E-R diagram with two entities, ORDER and CUSTOMER, as shown above, and are asked to draw the relationship between them. If a given customer can place many orders and a given order can be by one or more customers, which of the following should be indicated in the relationship symbol between the two entities? A) 0:1 B) 1:1 C) 1:N D) N:1 E) N:M

E Diff: 2 Page Ref: 149-150

59) An entity whose identifier includes the identifier of another entity is a(n) ________. A) strong entity B) weak entity C) ID-dependent entity D) A and C E) B and C

E Diff: 2 Page Ref: 153-154

51) An advantage of denormalization is ________. A) faster updating B) faster querying C) less complex SQL in application code D) A and B E) B and C

E Diff: 3 Page Ref: 132-133

62) Which of the following is not true about subtype entities? A) Subtypes may be exclusive. B) The supertype and subtypes will have the same identifier. C) Subtypes are used to avoid a situation in which some attributes are required to be null. D) Subtypes have attributes that are required by the supertype. E) Subtypes can produce a closer-fitting data model.

E Diff: 3 Page Ref: 156-157

92) An entity whose identifier includes the identifier of another entity is called a(n) ________ entity.

ID-dependent Diff: 2 Page Ref: 153-154

90) The SQL keyword ________ can be used to count the number of nulls in a column.

IS NULL Diff: 1 Page Ref: 137-138

99) Relationships between supertypes and subtypes are called ________ relationships.

IS-A Diff: 2 Page Ref: 157

What are the four sets of minimum cardinalities that can be present in a 1:N binary relationship?

If we use the labels "Parent" and "Child" to represent, respectively, the one and many side of a 1:N relationship, we can then consider whether the parent and child must participate in the relationship. If one must participate, it is mandatory (M). If one does not have to participate it is optional (O). The four possible sets of minimum cardinalities are therefore: Parent optional and Child optional (O-O) Parent mandatory and Child optional (M-O) Parent optional and Child mandatory (O-M) Parent mandatory and Child mandatory (M-M)

Explain the representation of a many-to-many strong entity relationship in a relational database design.

Many-to-many relationships cannot be directly represented in a relational database design. Therefore, many-to-many relationships are essentially broken into two one-to-many relationships by creating an intersection table that represents the relationship itself. The intersection table takes its key as a combination of the keys of the two original, or parent, entities. Each of the parent entities has a one-to-many relationship with the intersection table that is represented by placing the keys of the parents into the intersection table.

70) ________ requires application programmers to write complex SQL since they will need to write subqueries and joins to recombine data stored in separate relations.

Normalization Diff: 2 Page Ref: 129 Fig 4-2

Explain the representation of a one-to-many strong entity relationship in a relational database design.

One-to-many relationships are represented by placing the primary key of the table on the one side of the relationship into the table on the many side of the relationship as a foreign key. The term parent refers to the table on the one side of a 1:N relationship, and the term child refers to the table on the many side of the 1:N relationship. Therefore, the rule for representing a one-to-many relationship can be summarized as "Place the key of the parent table in the child table as a foreign key."

How are one-to-one recursive relationships addressed using the relational model?

One-to-one recursive relationships are addressed just the same as one-to-one nonrecursive relationships. The only difference is that both of the related entity instances are in the same entity class. The key of either instance is placed in the other instance as a foreign key. In the case of a recursive relationship, this means that a new attribute is added to the entity class with a recursive relationship. For each instance, this new attribute will contain the value of the key attribute of the instance that is related.

Explain the pragmatic reason for using surrogate keys.

Primary keys are commonly included in indexes, and are used to identify records to be retrieved by users. The ideal primary key is short, numeric and fixed. When the primary key contains a lengthy text field, this creates a large amount of duplicated data that must be frequently manipulated. For these reasons, it is often practical to use a surrogate key that is generated by the system and is relatively small and easy to manipulate.

83) ________ often use several copies of a set of same data, where each copy is modified for a specific use.

Read-only databases Diff: 2 Page Ref: 134

64) To determine the number and type of columns in a table, use the SQL construct ________.

SELECT * Diff: 1 Page Ref: 128

65) To limit the number of rows retrieved from a table, use the SQL keyword ________.

TOP Diff: 1 Page Ref: 128

Using the VRG database as an example, briefly describe what a final database design consists of.

The obvious part of the database design is the ER drawing itself, for example as shown for VRG in Figure 6-39. However, this needs to be accompanied by a summary of the database design relationships as shown in Figure 6-40. This document summarizes the cardinalities of relationships. For each relationship, we need a set of actions to enforce the minimum cardinalities. These can be based on Figures 6-28(a) and 6-28(b), the examples for VRG are shown in Figures 6-41 and 6-42. Finally, we need a set of column characteristics for each table, as shown in Figure 6-43 for VRG.

Briefly describe the process of converting an extended E-R model into a relational database design.

To convert an extended E-R model into a relational database design, first tables and columns must be defined for each entity attribute. The attributes of the entity are represented as the columns of the table. Primary keys are then selected for each table, after which the relationships between the entities are represented through the creation of foreign keys. Next, constraints are specified. Finally the normalization is verified.

89) Null values are a problem because they are ________.

ambiguous Diff: 3 Page Ref: 137-138

75) A(n) ________ describes a characteristic of an entity.

attribute Diff: 1 Page Ref: 146

84) Relationships of degree two are referred to as ________ relationships.

binary Diff: 2 Page Ref: 148

83) A ________ is a relationship between two entities.

binary relationship Diff: 2 Page Ref: 148

85) When transforming a data model into a relational design, relationships of all degrees are treated as combinations of ________.

binary relationships Diff: 3 Page Ref: 148

75) A relation is in BCNF if every determinant is a(n) ________.

candidate key Diff: 2 Page Ref: 130

87) Relationships are classified by their ________.

cardinality Diff: 1 Page Ref: 149

80) E-R modeling recognizes both relationship ________ and relationship ________.

classes; instances Diff: 2 Page Ref: 147

77) A(n) ________ is an identifier consisting of two or more attributes.

composite identifier Diff: 2 Page Ref: 147

62) The first step in assessing table structure is to ________ and ________.

count rows; examine columns Diff: 2 Page Ref: 128-129 Fig 4-1

82) The ________ of a relationship is the number of entity classes in the relationship.

degree Diff: 2 Page Ref: 148

74) A relation is in BCNF if every ________ is a candidate key.

determinant Diff: 2 Page Ref: 130

97) An attribute that determines which subtype is appropriate is called a ________.

discriminator Diff: 2 Page Ref: 157

71) A(n) ________ is something that the users want to track in their environment.

entity Diff: 1 Page Ref: 145

73) Entities of a given type are grouped into ________.

entity classes Diff: 1 Page Ref: 145

74) A(n) ________ is the occurrence of a particular entity.

entity instance Diff: 1 Page Ref: 145

98) Subtypes can be ________ or ________.

exclusive; inclusive Diff: 2 Page Ref: 157

72) The method of constructing data models used in the text is the ________ model.

extended entity-relationship (E-R) Diff: 1 Page Ref: 145

69) The presence of one or more ________ in a relation means that we will not be able to eliminate all duplicated data in that table.

foreign keys Diff: 3 Page Ref: 129

86) The principle difference between an entity and a table is that you can express the relationship between entities without using ________.

foreign keys Diff: 3 Page Ref: 148

72) Relations in BCNF have no modification anomalies in regard to ________.

functional dependencies Diff: 3 Page Ref: 129

66) When examining data values as a part of assessing table structure, you should try to determine two types of dependencies: ________ and ________.

functional dependencies; multivalued dependencies Diff: 2 Page Ref: 128-129 Fig 4-1

76) A(n) ________ of an entity instance is one or more attributes that name or identify entity instances.

identifier Diff: 1 Page Ref: 146-147

78) A(n) ________ serves the same role for an entity that a key does for a table.

identifier Diff: 3 Page Ref: 147

94) E-R models use a(n) ________ to connect entities that are ID-dependent.

identifying relationship Diff: 2 Page Ref: 154

87) You are creating a BOAT table using existing data from multiple sources, and you find that you have "power boat blue", "boat, power, blue" and "blue power boat" as data values for the same column. This is an example of the ________ problem.

inconsistent values Diff: 1 Page Ref: 135-139

88) A relationship's ________ indicates the maximum number of entity instances that can participate in the relationship.

maximum cardinality Diff: 2 Page Ref: 149

89) The notation 1:N shows the relationship's ________.

maximum cardinality Diff: 2 Page Ref: 149

91) A relationship's ________ indicates the number of entity instances that must participate in the relationship.

minimum cardinality Diff: 2 Page Ref: 149, 150

68) The elimination of ________ and the reduction of ________ are advantages of normalization.

modification anomalies; duplicated data Diff: 3 Page Ref: 129 Fig 4-2

76) Anomalies from ________ are so serious that these structures must be eliminated.

multivalued dependencies Diff: 2 Page Ref: 132

85) Multivalued dependencies show up under a different name as the ________ problem.

multivalued, multicolumn Diff: 1 Page Ref: 135-139

86) If you have a table with a set of columns named "Child01", "Child02" and "Child03", the table has the ________ problem.

multivalued, multicolumn Diff: 1 Page Ref: 135-139

79) Read-only databases are ________ updated.

never Diff: 2 Page Ref: 132

88) A missing value is called a(n) ________.

null value Diff: 1 Page Ref: 137-138

90) In a 1:N relationship, ________ is on the one side of the relationship, and the ________ is on the many side of the relationship.

parent entity; child entity Diff: 2 Page Ref: 149

71) Relations are sometimes left unnormalized to improve ________.

performance Diff: 3 Page Ref: 129

67) When examining data values as a part of assessing table structure, you should try to determine three types of keys: the ________, any additional ________ and any ________.

primary key; candidate keys; foreign keys Diff: 2 Page Ref: 128-129 Fig 4-1

78) Creating a ________ database is a job often given to beginning database professionals.

read-only Diff: 1 Page Ref: 132

80) Normalization is seldom an advantage for a ________ database.

read-only Diff: 2 Page Ref: 132

100) Relationships among an entity instance of a single entity class are called ________ relationships.

recursive Diff: 2 Page Ref: 172

79) Entities can be associated with one another in ________.

relationships Diff: 1 Page Ref: 147

77) Writing SQL subqueries and joins against normalized tables is ________ compared to the code that must be written to handle anomalies from multivalued dependencies.

simple (or a similar word) Diff: 2 Page Ref: 132

93) An entity that represents something that can exist on its own is called a(n) ________ entity.

strong Diff: 1 Page Ref: 153

61) When you are given a set of tables and asked to create a database to store their data, the first step is to assess the tables' ________.

structure and content Diff: 1 Page Ref: 128-129 Fig 4-1

95) Entities containing optional sets of attributes are often represented using ________.

subtypes Diff: 2 Page Ref: 156-157

96) The ________ entity contains the attributes that are common to all subtypes.

supertype Diff: 1 Page Ref: 156-157

84) Denormalization is simplejoin the data together and store it in a(n) ________.

table (or relation) Diff: 1 Page Ref: 132-133

81) A relationship class may involve ________ entity classes.

two or more Diff: 3 Page Ref: 148