CPT-264 Chapter-9

Which of the following properties of a relation states that an entry at the intersection of each row and column is single-valued? A) Entries in cells are simple. B) Entries in columns are from the same set of values. C) Each row is unique. D) The sequence of rows is insignificant. E) The sequence of columns can be interchanged.

A) Entries in cells are simple.

Which of the following properties should be satisfied when the identifier of the entity type becomes the primary key of the corresponding relation? A) The value of the key must uniquely identify every row in the relation. B) The key should serve as a foreign key in at least two other relations. C) The key must be a composite of a primary key and a secondary key. D) The key should be an intelligent key. E) The key should allow for null values.

A) The value of the key must uniquely identify every row in the relation.

If an associative entity exists, then: A) a separate relation C is created; the primary key of relation C is a composite key consisting of the primary key for each of the two entities in the relationship. B) the primary keys of relation A and relation B become foreign keys in a new relation C. C) secondary keys are used to establish the relationship. D) place the primary key of either entity in the relation for the other entity or do this for both entities. E) none of the above should be done.

A) a separate relation C is created; the primary key of relation C is a composite key consisting of the primary key for each of the two entities in the relationship

For a binary many-to-many relationship existing between entity types A and B: A) a separate relation C is created; the primary key of relation C is a composite key consisting of the primary key for each of the two entities in the relationship. B) the primary keys of relation A and relation B become foreign keys in a new relation C. C) secondary keys are used to establish the relationship. D) place the primary key of either entity in the relation for the other entity or do this for both entities. E) none of the above.

A) a separate relation C is created; the primary key of relation C is a composite key consisting of the primary key for each of the two entities in the relationship.

The smallest unit of named application data recognized by system software is called a(n): A) field. B) table. C) row. D) relation. E) entity.

A) field.

An attribute that appears as a nonkey attribute in one relation and as a primary key attribute (or part of a primary key) in another relation is a: A) foreign key. B) candidate key. C) pointer. D) relationship key. E) marker.

A) foreign key.

If order number serves as the primary key in the order relation and also appears as a nonkey attribute in the invoice relation, then order number is said to be a: A) foreign key. B) candidate key. C) pointer. D) relationship key. E) marker.

A) foreign key.

A single name that is used for two or more different attributes best defines: A) homonym. B) synonym. C) transitive dependency. D) alias. E) antonym.

A) homonym.

Using the term "account" to refer to a checking account and also to a savings account is an example of a(n): A) homonym. B) synonym. C) transitive dependency. D) alias. E) antonym.

A) homonym.

A data integrity control that restricts the permissible values for data is called a(n): A) input mask. B) default value. C) range control. D) primary key. E) candidate key.

A) input mask.

The process of converting complex data structures into simple, stable data structures is referred to as: A) normalization. B) simplification. C) structuring. D) process modeling. E) relational conversion

A) normalization.

The primary deliverable from logical database design is: A) normalized relations. B) design specifications. C) an updated Baseline Project Plan. D) a list of alternatives design strategies. E) a production system.

A) normalized relations.

A field of data that can be used to located a related field or row of data is called a(n): A) pointer. B) key. C) entity. D) attribute. E) index.

A) pointer.

The most common style for a logical database model is the: A) relational database model. B) hierarchical database model. C) network database model. D) object-oriented database model. E) hybrid database model.

A) relational database model.

When each nonprimary key attribute is identified by the whole key, the relation is said to be in at least: A) second normal form. B) third normal form. C) fourth normal form. D) fifth normal form. E) a relational form.

A) second normal form.

For a unary M:N relationship: A) the entity type is modeled as one relation; a separate relation is created to represent the M:N relationship; the new relation has a composite key that consists of two attributes that both take their values from the same primary key. B) the entity type and the M:N relationship are modeled as one relation; a composite key consisting of two attributes that both take their values from the same primary key is used as the primary key for the relation. C) separate relations for the class and for each subclass are created; primary and foreign keys are established for each class. D) the primary key of the entity on the one side of the relationship serves as a foreign key in the relation on the many side of the relationship. E) none of the above is true.

A) the entity type is modeled as one relation; a separate relation is created to represent the M:N relationship; the new relation has a composite key that consists of two attributes that both take their values from the same primary key.

When transforming an E-R diagram into normalized relations, the identifier of the entity type becomes: A) the primary key of the corresponding relation. B) the foreign key in the corresponding relation. C) a nonkey attribute in the corresponding relation. D) a secondary key in the corresponding relation. E) a homonym in the corresponding relation.

A) the primary key of the corresponding relation.

During logical database design, the work of all systems development team members is coordinated and shared through: A) the project dictionary. B) scheduled weekly meetings. C) the project leader. D) JAD sessions. E) walkthroughs.

A) the project dictionary.

Merging relations is also referred to as: A) view integration. B) view consolidation. C) encompassing. D) normalizing. E) transforming.

A) view integration.

Which of the following is NOT a true statement regarding a relation? A) Each relation consists of a set of named columns and an arbitrary number of unnamed rows. B) Each column in a relation corresponds to an attribute of that relation. C) An entry at the intersection of each row and column has a single value. D) Each row in a relation corresponds to an attribute of that relation. E) The rows may be interchanged or stored in any sequence.

B) Each column in a relation corresponds to an attribute of that relation.

Which of the following statements is true regarding normalization? A) Normalization is a top-down process. B) Normalization produces a set of well-structured relations that contain all of the data mentioned in system inputs and outputs developed in human interface design. C) Through the use of anomalies, stable structures are produced. D) Normalization is an integrity constraint specifying that the value of an attribute in one relation depends on the value of the same attribute in another relation. E) Normalization is a coding scheme recognized by system software for representing organizational data.

B) Normalization produces a set of well-structured relations that contain all of the data mentioned in system inputs and outputs developed in human interface design.

"Create a relation with primary key and nonkeyattributes" is the relational representation for which E-R structure? A) Weak entity B) Regular entity C) Gerund D) IS-A relationship E) Transitive dependency

B) Regular entity

Which of the following is NOT associated with logical and physical database design? A) Structure the data in stable structures that are not likely to change over time and that have minimal redundancy. B) The preparation of a final conceptual model and the implementation of the database C) Develop a logical database design from which we can do physical database design. D) Develop a logical database design that reflects the actual data requirements that exist in the forms and reports of an information system. E) Translate a relational database model into a technical file and database design.

B) The preparation of a final conceptual model and the implementation of the database

If a relationship exists among three or more entities, then: A) recursive relationships must be established through the use of recursive foreign keys. B) a separate relation with a primary key that is the composite of the primary keys of each of the participating entities is created. C) separate relations are established for each class and for each of the subclasses. D) use the primary key of relation A as a foreign key in relations B and C. E) none of the above is done

B) a separate relation with a primary key that is the composite of the primary keys of each of the participating entities is created.

A binary one-to-many relationship in an E-R diagram is best represented by: A) the creation of a separate relation; the primary key of this new relation is a composite key consisting of the primary key for each of the two entities in the relationship. B) adding the primary key attribute (or attributes) of the entity on the one side of the relationship as a foreign key in the relation that is on the many side of the relationship. C) adding the primary key attribute (or attributes) of the entity on the many side of the relationship as a foreign key in the relation that is on the one side of the relationship. D) creating a relation with a composite primary key and nonkey attributes. E) none of the above.

B) adding the primary key attribute (or attributes) of the entity on the one side of the relationship as a foreign key in the relation that is on the many side of the relationship.

Assume the structure of a relation is Employee (EmpID, Name, Dept, Salary). The number of attributes for this relation would: A) be three. B) be four. C) be five. D) be six. E) vary depending upon the number of employees.

B) be four.

A many-to-many relationship that associates certain items with their component items is called a: A) binary structure. B) bill-of-materials structure. C) binary relationship. D) ternary relationship. E) singular relationship.

B) bill-of-materials structure.

A particular relationship between two attributes best defines: A) context. B) functional dependency. C) normal form. D) structure. E) join.

B) functional dependency.

A foreign key in a relation that references the primary key values of that same relation is referred to as a: A) secondary key. B) recursive foreign key. C) composite key. D) complex key. E) concatenated key.

B) recursive foreign key.

Two different names that are used to refer to the same data item best defines: A) homonym. B) synonym. C) transitive dependency. D) alias. E) antonym.

B) synonym.

A default value is: A) the value that all fields will take. B) the value that a field will take unless otherwise specified. C) a value that is not allowed in a field. D) a way to represent null values. E) the value that a field always returns to.

B) the value that a field will take unless otherwise specified.

The dependence of nonprimary key attributes on other nonprimary key attributes best describes a: A) relationship dependency. B) transitive dependency. C)weak attribute. D) weak entity. E) weak relationship.

B) transitive dependency.

Which of the following is NOT a key step in logical database modeling and design? A) Combine normalized data requirements from all user interfaces into one consolidated logical database model. B) Compare the consolidated logical database design with the translated E-R model and produce, through view integration, one final logical database design for the application. C) Model how data flow through an information system, the relationships among the data flows, and how data come to be stored at specific locations. D) Translate the conceptual E-R data model for the application into normalized data requirements. E) Using normalization principles, develop a logical data model for each known user view for the application.

C) Model how data flow through an information system, the relationships among the data flows, and how data come to be stored at specific locations.

Using the normalized relation notation, an attribute of a relation which is the primary key of another relation is indicated by: A) an underline. B) a circle. C) a dashed underline. D) italics. E) a double-lined ellipse.

C) a dashed underline.

All of the following are objectives when choosing data types EXCEPT: A) minimizing storage space. B) representing all possible values. C) decrease data quality. D) improve data integrity. E) support all data manipulations desired on the field.

C) decrease data quality.

The process of splitting or combining normalized relations into physical tables based on affinity of use of rows and fields best describes: A) normalization. B) simplification. C) denormalization. D) data structure. E) nullifying.

C) denormalization.

Relationships between instances of a single entity type are referred to as: A) binary relationships. B) transitive relationships. C) recursive relationships. D) dependent relationships. E) singular relationships.

C) recursive relationships.

The integrity constraint that specifies that the value (or existence) of an attribute in one relation depends on the value (or existence) of the same attribute in another relation is called: A) foreign integrity. B) attribute integrity. C) referential integrity. D) dependence integrity. E) join integrity.

C) referential integrity.

A named two-dimensional table of data is a(n): A) network. B) tree structure. C) relation. D) tuple. E) object.

C) relation.

Each regular entity type in an E-R diagram is transformed into a: A) row in a relation. B) column in a relation. C) relation. D) tuple in a relation. E) database.

C) relation.

A data model that represents data in the form of tables or relations is called a(n): A) hierarchical database model. B) network database model. C) relational database model. D) hybrid database model. E) object-oriented database model.

C) relational database model.

For any relation R, if, for every valid instance of A, that at value of A uniquely determines the value of B: A) then a primary dependency exists in the relation. B) then A is said to be functionally dependent on B. C) then B is said to be functionally dependent on A. D) then A and B are candidate keys for the relation. E) None of the above is true.

C) then B is said to be functionally dependent on A.

A field that can be derived from other database fields is called a: A) quoted field. B) primary field. C) hidden field. D) calculated field. E) none of the above

D) calculated field.

All of the following are types of file organizations EXCEPT: A) indexed. B) sequential. C) hashed. D) logical.

D) logical.

The transformation of an E-R diagram into normalized relations and then the merging of all the relations into one final, consolidated set of relations requires all of the following steps EXCEPT: A) represent entities. B) represent relationships. C) normalize the relations. D) structure requirements. E) merge the relations.

D) structure requirements

The relation state specifying that nonprimary key attributes do not depend on other nonprimary key attributes is: A) first normal form. B) second normal form. C) Boyce-Codd normal form. D) third normal form. E) fifth normal form.

D) third normal form.

A functional dependency between two (or more) nonkey attributes in a relation defines a: A) weak dependency. B) partial dependency. C) simple dependency. D) transitive dependency. E) recursive dependency

D) transitive dependency.

Combining all normalized user views into one consolidated logical database model refers to: A) normalization. B) requirements structuring. C) file integration. D) view integration. E) logic modeling

D) view integration

A relation that contains a minimum amount of redundancy and allows users to insert, modify, and delete the rows in a table without errors or inconsistencies is a(n): A) independent relation. B) simple relation. C) unnormalized relation. D) well-structured relation. E) derived relation.

D) well-structured relation.

Which of the following is a purpose of logical and physical database design? A) Structure the data in stable structures that are not likely to change over time and that have minimal redundancy. B) Develop a logical database design that reflects the actual data requirements that exist in the forms and reports of an information system. C) Develop a logical database design from which we can do physical database design. D) Translate a relational database model into a technical file and database design. E) All of the above.

E) All of the above.

Which of the following best describes a unique sequential number or random number assigned by the database management system (DBMS) whenever a new record is added to a table? A) Number B) Currency C) OLE object D) Hyperlink E) Autonumber

E) Autonumber

During physical design, you consider: A) the definitions of each attribute. B) the descriptions of where and when data are entered, retrieved, deleted, and updated. C) the expectations for response time and data integrity. D) the descriptions of the file and database technologies to be used. E) all of the above.

E) all of the above.

Key physical database design decisions include: A) choosing the storage format for each attribute from the logical database model. B) grouping attributes from the logical database model into physical records. C) arranging related records in secondary memory so that individual and groups of records can be stored, retrieved, and updated rapidly. D) selecting media and structures for storing data to make access more efficient. E) all of the above.

E) all of the above.

For a binary one-to-one relationship between two entities A and B, the relationship is represented by: A) adding the primary key of A as a foreign key of B. B) adding the primary key of B as a foreign key of A. C) combining the two entities into one relation. D) creating a third relation to represent the relationship between the two entities. E) either A or B.

E) either A or B.

For a unary one-to-one relationship between two entities A and B, the relationship is represented by: A) adding the primary key of A as a foreign key of B. B) adding the primary key of B as a foreign key of A. C) combining the two entities into one relation. D) creating a third relation to represent the relationship between the two entities. E) either A or B.

E) either A or B.

An entity whose primary key depends on the primary key of another entity is called a: A) referential entity. B) candidate entity. C) transitive entity. D) dependent entity. E) weak entity.

E) weak entity.