SSD7 选择题。Multiple-Choice View Assessment Result: M

文件名称: SSD7 选择题。Multiple-Choice

所属分类: C

开发工具:

文件大小: 259kb

下载次数: 0

上传时间: 2010-01-04

提供者: peng****

下载 (259kb)

不能下载？报告错误

详细说明： View Assessment Result: Multiple-Choice Quiz 2 Your performance was as follows: 1. The degree of a table is the number of _____ in the table. (a) keys (b) columns (c) rows (d) foreign keys Correct answer is (b) Your score on this question is: 10.00 Feedback: (b) -------------------------------------------------------------------------------- 2. The arity of a table is the number of _____ in the table. (a) keys (b) columns (c) foreign keys (d) rows Correct answer is ( b) Your score on this question is: 10.00 Feedback: (b) -------------------------------------------------------------------------------- 3. What information is necessary when specifying the structure of a table? (a) the name of the table and the amount of storage space to be allocated to the table (b) the name of the table, the names of the table's attributes, the data types of the table's attributes, the formats of the table's attributes, and the maximum number of rows that the table can have (c) the name of the table and the names of the table's attributes (d) the name of the table, the names of the table's attributes, the data types of attributes, and the formats of attributes Correct answer is (d) Your score on this question is: 10.00 Feedback: (d) -------------------------------------------------------------------------------- 4. The foreign key in a table T1 _____ the same _____ as the corresponding primary key in table T2. must have, name need not have, name must have, domain (a) I, II, and III (b) I and II (c) I and III (d) II and III Correct answer is (d) Your score on this question is: 10.00 Feedback: (d) -------------------------------------------------------------------------------- 5. Which of the following SQL statements can be used to add a row to a table? (a) CREATE (b) INSERT (c) APPEND (d) ADD Correct answer is (b) Your score on this question is: 10.00 Feedback: (b) -------------------------------------------------------------------------------- 6. A difference operation can be applied to tables that (a) are union compatible (b) have the same column names (c) have the same name (d) are the same size Correct answer is (a) Your score on this question is: 10.00 Feedback: (a) -------------------------------------------------------------------------------- 7. Which of the following SQL statements can be used to create a relational table? (a) INSERT (b) ADD (c) CREATE (d) APPEND Correct answer is (c) Your score on this question is: 10.00 Feedback: (c) -------------------------------------------------------------------------------- 8. For two tables to be union compatible, the tables should be the same with respect to which of the following? (a) keys (b) cardinality (c) name (d) degree Correct answer is (d) Your score on this question is: 0.00 Feedback: (b) -------------------------------------------------------------------------------- 9. A deletion operation will _____ if the deletion leads to the violation of a referential integrity constraint. (a) fail (b) succeed with warning (c) succeed without warning (d) crash the system Correct answer is (a) Your score on this question is: 10.00 Feedback: (a) -------------------------------------------------------------------------------- 10. With Query By Example, a user enters a query by (a) filling in skeleton tables of the database with examples of what is to be retrieved (b) placing SQL keywords, such as select, under the column names they want to retrieve (c) typing a syntactically correct SQL query that uses column and table names similar to the correct column and table names in a database (d) writing an English description of the data that the user needs Correct answer is (a) Your score on this question is: 10.00 Feedback: See section 1.2.3 in the course notes. (a) -------------------------------------------------------------------------------- Go to top of assessment. Total score: 90.00 ? Copyright 2008 iCarnegie, Inc. All rights reserved. 1. In the Entity-Relationship model, the degree of a relationship specifies which of the following? (a) The cardinality ratio of the relationship (b) The number of integrity constraints required to implement the relationship (c) The number of attributes that characterize the relationship (d) The number of entities that participate in the relationship Correct answer is (d) 2. In an ER model, which of the following is true about a component attribute? (a) A component attribute is always atomic. (b) Component attributes must always be combined by an aggregation operation. (c) A component attribute can be a composite attribute. (d) A component attribute always contains other components. Correct answer is (c) 3. In the Entity-Relationship model, properties that characterize entities and relationships are modeled as (a) attributes (b) participation constraints (c) entity types (d) weak entities Correct answer is (a) 4. What is an identifying owner in an ER model? (a) The entity upon which a weak entity's existence depends (b) The relationship that identifies a weak entity's owner (c) The entity upon which a strong entity's existence depends (d) The relationship that identifies a strong entity's owner Correct answer is (a) 5. In an ER model, the cardinality ratio of a relationship type is (a) the number of instances of relationships of that relationship type (b) the number of entity types involved in that relationship type (c) the number of relationships of that relationship type in which an entity can participate (d) the minimum number of entities that can participate in that relationship type Correct answer is (c) 6. Which of the following is true about storage for derived attributes? (a) Derived attributes must not be stored. (b) Derived attributes are usually stored because storage improves retrieval performance. (c) Derived attributes must be stored. (d) Derived attributes are usually not stored because they can be computed. Correct answer is (d) 7. In an ER model, what is a recursive relationship type? (a) A never-ending type of relationship (b) The type of relationship that does not belong anywhere (c) The type of relationship between entities of one entity type (d) The relationship type where the related entities are one and the same Correct answer is (c) 8. In EER modeling, generalization is the process of generating (a) superclasses out of subclasses (b) subclasses out of superclasses (c) entities out of attributes (d) attributes out of entities Correct answer is (a) 9. When mapping from an ER model to a relational model, a strong entity is mapped into a (a) table (b) row (c) column (d) key Correct answer is (a) 10. Which of the following is true about attributes in a relational model? Attributes can be multi-valued. Attributes can be composite. (a) Both I and II (b) II only (c) Neither I nor II (d) I only Correct answer is (c) 1. In an ER model, what is a recursive relationship type? (a) The relationship type where the related entities are one and the same (b) The type of relationship that does not belong anywhere (c) The type of relationship between entities of one entity type (d) A never-ending type of relationship Correct answer is (c) 2. In an ER model, the cardinality ratio of a relationship type is (a) the number of relationships of that relationship type in which an entity can participate (b) the minimum number of entities that can participate in that relationship type (c) the number of entity types involved in that relationship type (d) the number of instances of relationships of that relationship type Correct answer is (a) 3. In the Entity-Relationship model, a derived attribute is one (a) that is composed of multiple atomic attributes (b) that characterizes a relationship instead of an entity (c) that may have multiple values simultaneously (d) whose value can be computed from the values of other attributes Correct answer is (d) 4. In the Entity-Relationship model, properties that characterize entities and relationships are modeled as (a) entity types (b) weak entities (c) attributes (d) participation constraints Correct answer is (c) 5. Which of the following is true about storage for derived attributes? (a) Derived attributes must be stored. (b) Derived attributes are usually stored because storage improves retrieval performance. (c) Derived attributes must not be stored. (d) Derived attributes are usually not stored because they can be computed. Correct answer is (d) 6. What is an identifying owner in an ER model? (a) The relationship that identifies a weak entity's owner (b) The relationship that identifies a strong entity's owner (c) The entity upon which a strong entity's existence depends (d) The entity upon which a weak entity's existence depends Correct answer is (d) 7. In an ER model, which of the following is true about a component attribute? (a) A component attribute always contains other components. (b) A component attribute can be a composite attribute. (c) A component attribute is always atomic. (d) Component attributes must always be combined by an aggregation operation. Correct answer is (b) 8. In EER modeling, generalization is the process of generating (a) attributes out of entities (b) superclasses out of subclasses (c) subclasses out of superclasses (d) entities out of attributes Correct answer is (b) 9. When mapping from an ER model to a relational model, a strong entity is mapped into a (a) key (b) row (c) column (d) table Correct answer is (d) 10. Which of the following is true about attributes in a relational model? Attributes can be multi-valued. Attributes can be composite. (a) I only (b) II only (c) Neither I nor II (d) Both I and II Correct answer is (c) 1. Through normalization, update anomalies (a) can be eliminated (b) is usually left unchanged (c) can be maximized (d) can be minimized but not eliminated Correct answer is (a) 2. Which of the following is a property (are properties) exhibited by good relational schemas? The use of null values in tuples The grouping of as many attributes as possible into one main table The elimination of data redundancy to avoid update anomalies (a) III only (b) None (c) I and II only (d) II and III only Correct answer is (a) 3. Which of the following statements concerning normal forms is true? (a) A relation that is in second normal form is also in first normal form. (b) The lower the normal form number, the better the schema design is. (c) Each normal form contains a state of independent properties, unrelated to other normal forms. (d) Schemas that are in second normal form are considered the best. Correct answer is (a) 4. Consider the following functional dependency. {A, B} -> {C} Regarding this dependency, which of the following statements is (are) true? The values of C are uniquely determined by the values of A. The values of A are uniquely determined by the values of C. (a) None (b) II only (c) I only (d) I and II Correct answer is (a) 5. Which of the following problems can be caused by data redundancy in a relational schema? Inefficient use of space Update anomalies and possible loss of data Inefficient use of processing time (a) I and II only (b) I and III only (c) I, II, and III (d) II only Correct answer is (c) 6. Consider a table with atomic attributes A, B, and C and the following functional dependencies. A -> B B -> C If the primary key of this table is attribute A, then this relation satisfies which of the following normal forms? First Second Third (a) None (b) I only (c) I, II and III (d) I and II only Correct answer is (d) 7. For a relation to be in 3NF, it should not contain _____ attribute that is transitively dependent on _____. (a) a non-primary key, a foreign key (b) a primary key, a non-primary key (c) a primary key, a foreign key (d) a non-primary key, the primary key Correct answer is (d) 8. The FD X -> Y is a full dependency in a relation R, if there is _____ attribute A that can be _____ X and the dependency still holds. (a) no, added to (b) no, removed from (c) at least one, removed from (d) at least one, added to Correct answer is (b) 9. For a relation to be in 2NF, _____ attribute must be fully functionally dependent on _____. (a) every non-primary-key, the primary key (b) every alternate key, the primary key (c) every non-key, every key (d) every non-key, at least one key Correct answer is (a) 10. The FD X -> Y is a partial dependency in a relation R, if there is _____ attribute A that can be _____ X and the dependency still holds. (a) at least one, removed from (b) at least one, added to (c) no, added to (d) no, removed from Correct answer is (a) 1. Through normalization, update anomalies (a) can be eliminated (b) is usually left unchanged (c) can be minimized but not eliminated (d) can be maximized Correct answer is (a) 2. Consider the following functional dependency. {A, B} -> {C} Regarding this dependency, which of the following statements is (are) true? The values of C are uniquely determined by the values of A. The values of A are uniquely determined by the values of C. (a) None (b) I and II (c) I only (d) II only Correct answer is (a) 3. Which of the following is a property (are properties) exhibited by good relational schemas? The use of null values in tuples The grouping of as many attributes as possible into one main table The elimination of data redundancy to avoid update anomalies (a) III only (b) None (c) II and III only (d) I and II only Correct answer is (a) 4. Through normalization, data redundancy (a) can be eliminated (b) can be maximized (c) can be minimized but not eliminated (d) are usually left unchanged Correct answer is (a) 5. Which of the following statements concerning normal forms is true? (a) A relation that is in second normal form is also in first normal form. (b) Each normal form contains a state of independent properties, unrelated to other normal forms. (c) Schemas that are in second normal form are considered the best. (d) The lower the normal form number, the better the schema design is. Correct answer is (a) 6. For a relation to be in 3NF, it should not contain _____ attribute that is transitively dependent on _____. (a) a primary key, a foreign key (b) a primary key, a non-primary key (c) a non-primary key, a foreign key (d) a non-primary key, the primary key Correct answer is (d) 7. The FD X -> Y is a full dependency in a relation R, if there is _____ attribute A that can be _____ X and the dependency still holds. (a) no, removed from (b) at least one, removed from (c) at least one, added to (d) no, added to Correct answer is (a) 8. Consider a table with atomic attributes A, B, and C and the following functional dependencies. A -> B B -> C If the primary key of this table is attribute A, then this relation satisfies which of the following normal forms? First Second Third (a) I, II and III (b) None (c) I and II only (d) I only Correct answer is (c) 9. For a relation to be in 2NF, _____ attribute must be fully functionally dependent on _____. (a) every alternate key, the primary key (b) every non-key, at least one key (c) every non-key, every key (d) every non-primary-key, the primary key Correct answer is (d) 10. The FD X -> Y is a partial dependency in a relation R, if there is _____ attribute A that can be _____ X and the dependency still holds. (a) no, added to (b) no, removed from (c) at least one, added to (d) at least one, removed from Correct answer is (d) 1. What is an identifying owner in an ER model? (a) The entity upon which a weak entity's existence depends (b) The relationship that identifies a weak entity's owner (c) The relationship that identifies a strong entity's owner (d) The entity upon which a strong entity's existence depends Correct answer is (a) 2. In an ER model, the cardinality ratio of a relationship type is (a) the minimum number of entities that can participate in that relationship type (b) the number of instances of relationships of that relationship type (c) the number of entity types involved in that relationship type (d) the number of relationships of that relationship type in which an entity can participate Correct answer is (d) 3. In the Entity-Relationship model, properties that characterize entities and relationships are modeled as (a) entity types (b) participation constraints (c) weak entities (d) attributes Correct answer is (d) 4. In an ER model, what is a recursive relationship type? (a) A never-ending type of relationship (b) The relationship type where the related entities are one and the same (c) The type of relationship between entities of one entity type (d) The type of relationship that does not belong anywhere Correct answer is (c) 5. In the Entity-Relationship model, a derived attribute is one (a) that characterizes a relationship instead of an entity (b) that may have multiple values simultaneously (c) whose value can be computed from the values of other attributes (d) that is composed of multiple atomic attributes Correct answer is (c) 6. In the Entity-Relationship model, the degree of a relationship specifies which of the following? (a) The number of attributes that characterize the relationship (b) The number of entities that participate in the relationship (c) The cardinality ratio of the relationship (d) The number of integrity constraints required to implement the relationship Correct answer is (b) 7. Which of the following is true about storage for derived attributes? (a) Derived attributes are usually not stored because they can be computed. (b) Derived attributes are usually stored because storage improves retrieval performance. (c) Derived attributes must be stored. (d) Derived attributes must not be stored. Correct answer is (a) 8. In EER modeling, generalization is the process of generating (a) superclasses out of subclasses (b) entities out of attributes (c) subclasses out of superclasses (d) attributes out of entities Correct answer is (a) 9. When mapping from an ER model to a relational model, a strong entity is mapped into a (a) key (b) table (c) row (d) column Correct answer is (b) 10. Which of the following is true about attributes in a relational model? Attributes can be multi-valued. Attributes can be composite. (a) II only (b) I only (c) Both I and II (d) Neither I nor II Correct answer is (d) 1. Which of the following is true about storage for derived attributes? (a) Derived attributes are usually stored because storage improves retrieval performance. (b) Derived attributes must be stored. (c) Derived attributes are usually not stored because they can be computed. (d) Derived attributes must not be stored. Correct answer is (c) 2. In an ER model, the cardinality ratio of a relationship type is (a) the minimum number of entities that can participate in that relationship type (b) the number of entity types involved in that relationship type (c) the number of relationships of that relationship type in which an entity can participate (d) the number of instances of relationships of that relationship type Correct answer is (c) 3. In the Entity-Relationship model, the degree of a relationship specifies which of the following? (a) The number of attributes that characterize the relationship (b) The number of integrity constraints required to implement the relationship (c) The cardinality ratio of the relationship (d) The number of entities that participate in the relationship Correct answer is (d) 4. In the Entity-Relationship model, properties that characterize entities and relationships are modeled as (a) weak entities (b) participation constraints (c) attributes (d) entity types Correct answer is (c) Your score on this question is: 0.00 5. A weak entity type implies a (a) weak relationship type (b) relationship with total participation constraint (c) strong relationship type (d) relationship with partial participation constraint Correct answer is (b) 6. In an ER model, which of the following is true about a component attribute? (a) A component attribute can be a composite attribute. (b) Component attributes must always be combined by an aggregation operation. (c) A component attribute always contains other components. (d) A component attribute is always atomic. Correct answer is (a) 7. In the Entity-Relationship model, a derived attribute is one (a) that characterizes a relationship instead of an entity (b) that is composed of multiple atomic attributes (c) whose value can be computed from the values of other attributes (d) that may have multiple values simultaneously Correct answer is (c) 1. Through normalization, update anomalies (a) is usually left unchanged (b) can be minimized but not eliminated (c) can be maximized (d) can be eliminated Correct answer is (d) 2. Which of the following problems can be caused by data redundancy in a relational schema? Inefficient use of space Update anomalies and possible loss of data Inefficient use of processing time (a) I and II only (b) I and III only (c) II only (d) I, II, and III Correct answer is (d) 3. Consider the following functional dependency. {A, B} -> {C} Regarding this dependency, which of the following statements is (are) true? The values of C are uniquely determined by the values of A. The values of A are uniquely determined by the values of C. (a) I only (b) I and II (c) II only (d) None Correct answer is (d) 4. Which of the following is a property (are properties) exhibited by good relational schemas? The use of null values in tuples The grouping of as many attributes as possible into one main table The elimination of data redundancy to avoid update anomalies (a) III only (b) II and III only (c) I and II only (d) None Correct answer is (a) 5. Which of the following statements concerning normal forms is true? (a) Schemas that are in second normal form are considered the best. (b) Each normal form contains a state of independent properties, unrelated to other normal forms. (c) A relation that is in second normal form is also in first normal form. (d) The lower the normal form number, the better the schema design is. Correct answer is (c) 6. The FD X -> Y is a partial dependency in a relation R, if there is _____ attribute A that can be _____ X and the dependency still holds. (a) at least one, added to (b) at least one, removed from (c) no, removed from (d) no, added to Correct answer is (b) 7. For a relation to be in 2NF, _____ attribute must be fully functionally dependent on _____. (a) every non-primary-key, the primary key (b) every non-key, at least one key (c) every non-key, every key (d) every alternate key, the primary key Correct answer is (a) 8. Consider a table with atomic attributes A, B, and C and the following functional dependencies. A -> B B -> C If the primary key of this table is attribute A, then this relation satisfies which of the following normal forms? First Second Third (a) I only (b) None (c) I and II only (d) I, II and III Correct answer is (c) 9. The FD X -> Y is a full dependency in a relation R, if there is _____ attribute A that can be _____ X and the dependency still holds. (a) no, removed from (b) at least one, removed from (c) at least one, added to (d) no, added to Correct answer is (a) 10. For a relation to be in 3NF, it should not contain _____ attribute that is transitively dependent on _____. (a) a primary key, a foreign key (b) a non-primary key, a foreign key (c) a non-primary key, the primary key (d) a primary key, a non-primary key Correct answer is (c) 1. Which of the following statements concerning normal forms is true? (a) The lower the normal form number, the better the schema design is. (b) A relation that is in second normal form is also in first normal form. (c) Schemas that are in second normal form are considered the best. (d) Each normal form contains a state of independent properties, unrelated to other normal forms. Correct answer is (b) 2. Consider the following functional dependency. {A, B} -> {C} Regarding this dependency, which of the following statements is (are) true? The values of C are uniquely determined by the values of A. The values of A are uniquely determined by the values of C. (a) I only (b) II only (c) I and II (d) None Correct answer is (d) 3. Which of the following problems can be caused by data redundancy in a relational schema? Inefficient use of space Update anomalies and possible loss of data Inefficient use of processing time (a) I, II, and III (b) I and II only (c) I and III only (d) II only Correct answer is (a) Y 4. Through normalization, update anomalies (a) can be eliminated (b) can be maximized (c) is usually left unchanged (d) can be minimized but not eliminated Correct answer is (a) 5. Which of the following is a property (are properties) exhibited by good relational schemas? The use of null values in tuples The grouping of as many attributes as possible into one main table The elimination of data redundancy to avoid update anomalies (a) I and II only (b) III only (c) None (d) II and III only Correct answer is (b) 6. Consider a table with atomic attributes A, B, and C and the following functional dependencies. A -> B B -> C If the primary key of this table is attribute A, then this relation satisfies which of the following normal forms? First Second Third (a) I and II only (b) I only (c) I, II and III (d) None Correct answer is (a) 7. For a relation to be in 3NF, it should not contain _____ attribute that is transitively dependent on _____. (a) a non-primary key, a foreign key (b) a primary key, a foreign key (c) a primary key, a non-primary key (d) a non-primary key, the primary key Correct answer is (d) 8. The FD X -> Y is a partial dependency in a relation R, if there is _____ attribute A that can be _____ X and the dependency still holds. (a) at least one, added to (b) no, removed from (c) no, added to (d) at least one, removed from Correct answer is (d) 9. For a relation to be in 2NF, _____ attribute must be fully functionally dependent on _____. (a) every non-primary-key, the primary key (b) every alternate key, the primary key (c) every non-key, every key (d) every non-key, at least one key Correct answer is (a) 10. The FD X -> Y is a full dependency in a relation R, if there is _____ attribute A that can be _____ X and the dependency still holds. (a) no, added to (b) at least one, removed from (c) at least one, added to (d) no, removed from Correct answer is (d) 1. In an ER model, which of the following is true about a composite attribute? (a) A composite attribute can have a method attached to it. (b) A composite attribute cannot be broken into more basic attributes. (c) A composite attribute can be broken into more basic attributes. (d) A composite attribute can only be designed by users with special privileges. Correct answer is (c) 2. The term physical data independence refers to the ability to change (a) the physical layout of the data without changing the external schemas, the conceptual schemas, or the application programs (b) the data without physically relocating the tables (c) the conceptual schema without changing the application programs (d) the application programs without changing the conceptual schema Correct answer is (a) 3. What attributes does a subclass have? (a) None of the attributes of its superclass (b) All the attributes of its superclass, and possibly more (c) Just the attributes from the superclass (d) A subset of the attributes of its superclass Correct answer is (b) 4. If X -> Y, which of the following would make Y fully dependent on X? (a) Y is a single attribute (b) X is a single attribute (c) X consists of multiple attributes (d) Y consists of multiple attributes Correct answer is (b) 5. In an ER model, what is the degree of a relationship type? (a) The validity of the relationship type (b) The strength of the relationship type (c) The number of entity types participating in the relationship type (d) The number of instances of the relationship type Correct answer is (c) 6. Database design typically consists of which of the following phases? Conceptual design Logical design Physical design (a) II only (b) I, II, and III (c) II and III only (d) I only Correct answer is (b) 7. A relational schema is in first normal form, if the domain of all of its (a) primary keys are not multi-valued (b) primary keys and alternate keys are not multi-valued (c) primary keys are not composite (d) attributes can take on only atomic values Correct answer is (d) 8. In an ER model, a derived attribute is one whose values (a) have been derived at some time in the past (b) can be derived from the values of some other attributes (c) can be derived from the system tables (d) can be derived from another table Correct answer is (b) 9. Y is transitively dependent on X, if (a) X -> Y and A -> Y (b) X -> A, B and A -> Y (c) X -> Y and Y -> A (d) X -> A, B and Y -> A, B Correct answer is (b) 10. Relationships in an ER model are primarily translated to which of the following in a relational model? (a) relationships (b) primary keys and foreign keys (c) three-way tables (d) dummy relationship tables Correct answer is (b) View Assessment Result With Query By Example, a user enters a query by (a) filling in skeleton tables of the database with examples of what is to be retrieved (b) placing SQL keywords, such as select, under the column names they want to retrieve (c) writing an English description of the data that the user needs (d) typing a syntactically correct SQL query that uses column and table names similar to the correct column and table names in a database F Your performance was as follows: You took 2 minutes on this assessment from Tue Mar 17 05:22:13 UTC+0800 2009 to Tue Mar 17 05:24:13 UTC+0800 2009. Total score: 100.00 1. An E-Commerce system consists of the following components. Which of the same components must be included in a database management system? 1 The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 2 A collection of programs must be included that control the data, such as programs to create, maintain, and manipulate the data. These programs can be easily used to create, maintain, and manipulate data in other domains, such as in a library information system. 3 A collection of programs that operate on the data, but are specific to the E-commerce system. These programs enable users to browse through the store-items, place orders, track shipping, etc. (a) II only (b) I, II, and III (c) I only (d) II and III only Correct answer is (a) Your score on this question is: 14.29 Feedback: A DBMS refers to just the set of general-purpose programs to control data. (a) 2. An E-Commerce system consists of the following components. Which of these same components will constitute a database system? 4 The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 5 A collection of programs that control the data, such as programs to create, maintain, and manipulate the data constitutes a database system. These programs can be easily used to create, maintain, and manipulate data in other domains such as in a library information system. 6 A collection of programs that operate on the data, but are specific to the E-commerce system, constitutes a database system. These programs enable users to browse through the store-items, place orders, track shipping, etc. (a) I only (b) I, II, and III (c) I and II only (d) II only Correct answer is (b) Your score on this question is: 14.29 Feedback: A database system includes the data, the DBMS, and the application-specific programs that operate on that data. (b) 3. An E-Commerce system consists of the following components. Which of these same components must be included in a database? 7 The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 8 A database must include a collection of programs that control the data, such as programs to create, maintain, and manipulate the data. These programs can be easily used to create, maintain, and manipulate data in other domains. 9 A database must include a collection of programs that operate on the data, but are specific to the E-commerce system. These programs enable users to browse through the store-items, place orders, track shipping, etc. (a) I and II only (b) I only (c) II only (d) I, II, and III Correct answer is (b) Your score on this question is: 14.29 Feedback: Database refers to just the data (b) 4. An E-Commerce database contains data about customers, products, orders, system response times, etc. Which of the following can be specified as integrity constraints in an E-Commerce database system? 10 No two products can have the same product ID. 11 The DBMS response time for all Web requests should be at most 2 seconds. 12 A customer order cannot have more than one shipping address. (a) I and III only (b) I and II only (c) I only (d) I, II, and III Correct answer is (a) Your score on this question is: 14.29 Feedback: The constraints I, II and III specify the application semantics of the data captured in the E-Commerce database. Constraint II, although it seems contrary to common sense, is not something that can be prohibited by the DBMS because the DBMS is general purpose. The response time of the DBMS cannot be enforced by the DBMS. It depends on factors such the processor speed, memory available, etc. (a) 5. In a database system, whose responsibility is it to provide data consistency? (a) the user's (b) the application programmer's (c) the DBMS's (d) the database administrator's Correct answer is (c) Your score on this question is: 14.29 Feedback: (c) 6. A database is needed for which of the following application scenarios? 13 A video store that needs to keep track of data about members, about videos carried by the store, about videos rented by members, as well as data concerning borrow-date, return-date, and payment information. 14 In the human resources department of a company, information about employees, their titles, their salaries and sick days, and about vacation days taken by each employee. 15 A computer-simulated video game which needs to calculate and display, the physical (x, y) location of each actor in the game, the speed with which they are moving at the current instant, the direction in which they are moving, the action they are performing, the angle at which the game-player is viewing the scene. (a) I only (b) I, II, and III (c) I and II only (d) I and III only Correct answer is (c) Your score on this question is: 14.29 Feedback: (c) 7. The physical storage structure will be _____ to the application programmer in a database approach, and will be _____ to the application programmer in a file system approach. (a) hidden, hidden (b) hidden, visible (c) visible, visible (d) visible, hidden Correct answer is (b) Your score on this question is: 14.29 Feedback: The layer of abstraction offered by a DBMS hides the physical storage structure from the application programmer. (b) Go to top of assessment. Total score: 100.00 Your performance was as follows: You took 3 minutes on this assessment from Tue Mar 17 04:27:27 UTC+0800 2009 to Tue Mar 17 04:30:02 UTC+0800 2009. Total score: 85.71 1. An E-Commerce system consists of the following components. Which of these same components must be included in a database? 1 The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 2 A database must include a collection of programs that control the data, such as programs to create, maintain, and manipulate the data. These programs can be easily used to create, maintain, and manipulate data in other domains. 3 A database must include a collection of programs that operate on the data, but are specific to the E-commerce system. These programs enable users to browse through the store-items, place orders, track shipping, etc. (a) II only (b) I and II only (c) I only (d) I, II, and III Correct answer is (c) Your score on this question is: 14.29 Feedback: Database refers to just the data (c) 2. In a database system, whose responsibility is it to provide data consistency? (a) the database administrator's (b) the user's (c) the application programmer's (d) the DBMS's Correct answer is (d) Your score on this question is: 14.29 Feedback: (d) 3. An E-Commerce system consists of the following components. Which of these same components will constitute a database system? 4 The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 5 A collection of programs that control the data, such as programs to create, maintain, and manipulate the data constitutes a database system. These programs can be easily used to create, maintain, and manipulate data in other domains such as in a library information system. 6 A collection of programs that operate on the data, but are specific to the E-commerce system, constitutes a database system. These programs enable users to browse through the store-items, place orders, track shipping, etc. (a) I, II, and III (b) I only (c) I and II only (d) II only Correct answer is (a) Your score on this question is: 14.29 Feedback: A database system includes the data, the DBMS, and the application-specific programs that operate on that data. (a) 4. An E-Commerce system consists of the following components. Which of the same components must be included in a database management system? 7 The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 8 A collection of programs must be included that control the data, such as programs to create, maintain, and manipulate the data. These programs can be easily used to create, maintain, and manipulate data in other domains, such as in a library information system. 9 A collection of programs that operate on the data, but are specific to the E-commerce system. These programs enable users to browse through the store-items, place orders, track shipping, etc. (a) I only (b) I, II, and III (c) II only (d) II and III only Correct answer is (c) Your score on this question is: 0.00 Feedback: A DBMS refers to just the set of general-purpose programs to control data. (d) 5. An E-Commerce database contains data about customers, products, orders, system response times, etc. Which of the following can be specified as integrity constraints in an E-Commerce database system? 10 No two products can have the same product ID. 11 The DBMS response time for all Web requests should be at most 2 seconds. 12 A customer order cannot have more than one shipping address. (a) I, II, and III (b) I only (c) I and II only (d) I and III only Correct answer is (d) Your score on this question is: 14.29 Feedback: The constraints I, II and III specify the application semantics of the data captured in the E-Commerce database. Constraint II, although it seems contrary to common sense, is not something that can be prohibited by the DBMS because the DBMS is general purpose. The response time of the DBMS cannot be enforced by the DBMS. It depends on factors such the processor speed, memory available, etc. (d) 6. A database is needed for which of the following application scenarios? 13 A video store that needs to keep track of data about members, about videos carried by the store, about videos rented by members, as well as data concerning borrow-date, return-date, and payment information. 14 In the human resources department of a company, information about employees, their titles, their salaries and sick days, and about vacation days taken by each employee. 15 A computer-simulated video game which needs to calculate and display, the physical (x, y) location of each actor in the game, the speed with which they are moving at the current instant, the direction in which they are moving, the action they are performing, the angle at which the game-player is viewing the scene. (a) I and II only (b) I only (c) I, II, and III (d) I and III only Correct answer is (a) Your score on this question is: 14.29 Feedback: (a) 7. The physical storage structure will be _____ to the application programmer in a database approach, and will be _____ to the application programmer in a file system approach. (a) visible, hidden (b) hidden, hidden (c) hidden, visible (d) visible, visible Correct answer is (c) Your score on this question is: 14.29 Feedback: The layer of abstraction offered by a DBMS hides the physical storage structure from the application programmer. (c) Go to top of assessment. Total score: 85.71 Total score: 42.86 1. An E-Commerce system consists of the following components. Which of these same components must be included in a database? 1 The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 2 A database must include a collection of programs that control the data, such as programs to create, maintain, and manipulate the data. These programs can be easily used to create, maintain, and manipulate data in other domains. 3 A database must include a collection of programs that operate on the data, but are specific to the E-commerce system. These programs enable users to browse through the store-items, place orders, track shipping, etc. (a) I and II only (b) I only (c) II only (d) I, II, and III Correct answer is (b) Your score on this question is: 14.29 Feedback: Database refers to just the data (b) 2. In a database system, whose responsibility is it to provide data consistency? (a) the DBMS's (b) the user's (c) the application programmer's (d) the database administrator's Correct answer is (a) Your score on this question is: 0.00 Feedback: (d) 3. An E-Commerce system consists of the following components. Which of these same components will constitute a database system? 4 The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 5 A collection of programs that control the data, such as programs to create, maintain, and manipulate the data constitutes a database system. These programs can be easily used to create, maintain, and manipulate data in other domains such as in a library information system. 6 A collection of programs that operate on the data, but are specific to the E-commerce system, constitutes a database system. These programs enable users to browse through the store-items, place orders, track shipping, etc. (a) II only (b) I and II only (c) I, II, and III (d) I only Correct answer is (c) Your score on this question is: 0.00 Feedback: A database system includes the data, the DBMS, and the application-specific programs that operate on that data. (a) 4. An E-Commerce system consists of the following components. Which of the same components must be included in a database management system? 7 The data, such as information about the goods available for sale, customers, orders placed, shipping information, etc. 8 A collection of programs must be included that control the data, such as programs to create, maintain, and manipulate the data. These programs can be easily used to create, maintain, and manipulate data in other domains, such as in a library information system. 9 A collection of programs that operate on the data, but are specific to the E-commerce system. These programs enable users to browse through the store-items, place orders, track shipping, etc. (a) I, II, and III (b) II only (c) I only (d) II and III only Correct answer is (b) Your score on this question is: 0.00 Feedback: A DBMS refers to just the set of general-purpose programs to control data. (d) 5. An E-Commerce database contains data about customers, products, orders, system response times, etc. Which of the following can be specified as integrity constraints in an E-Commerce database system? 10 No two products can have the same product ID. 11 The DBMS response time for all Web requests should be at most 2 seconds. 12 A customer order cannot have more than one shipping address. (a) I only (b) I and III only (c) I and II only (d) I, II, and III Correct answer is (b) Your score on this question is: 0.00 Feedback: The constraints I, II and III specify the application semantics of the data captured in the E-Commerce database. Constraint II, although it seems contrary to common sense, is not something that can be prohibited by the DBMS because the DBMS is general purpose. The response time of the DBMS cannot be enforced by the DBMS. It depends on factors such the processor speed, memory available, etc. (d) 6. A database is needed for which of the following application scenarios? 13 A video store that needs to keep track of data about members, about videos carried by the store, about videos rented by members, as well as data concerning borrow-date, return-date, and payment information. 14 In the human resources department of a company, information about employees, their titles, their salaries and sick days, and about vacation days taken by each employee. 15 A computer-simulated video game which needs to calculate and display, the physical (x, y) location of each actor in the game, the speed with which they are moving at the current instant, the direction in which they are moving, the action they are performing, the angle at which the game-player is viewing the scene. (a) I only (b) I and II only (c) I, II, and III (d) I and III only Correct answer is (b) Your score on this question is: 14.29 Feedback: (b) 7. The physical storage structure will be _____ to the application programmer in a database approach, and will be _____ to the application programmer in a file system approach. (a) visible, visible (b) visible, hidden (c) hidden, visible (d) hidden, hidden Correct answer is (c) Your score on this question is: 14.29 Feedback: The layer of abstraction offered by a DBMS hides the physical storage structure from the application programmer. (c) Go to top of assessment. The arity of a table is the number of _____ in the table. (a) rows (b) columns (c) keys (d) foreign keys Correct answer is (b) Your score on this question is: 10.00 Feedback: 2. The cardinality of a table is the number of _____ in the table. (a) rows (b) foreign keys (c) keys (d) columns Correct answer is (a) Your score on this question is: 10.00 Feedback: 3. The degree of a table is the number of _____ in the table. (a) rows (b) columns (c) foreign keys (d) keys Correct answer is (b) Your score on this question is: 10.00 Feedback: 4. The foreign key in a table T1 _____ the same _____ as the corresponding primary key in table T2. 1 must have, name 2 need not have, name 3 must have, domain (a) I and III (b) II and III (c) I, II, and III (d) I and II Correct answer is (b) Your score on this question is: 10.00 Feedback: 5. The SQL clause to perform a set UNION operation is (a) MELD (b) UNITE (c) UNION (d) COMBINE Correct answer is (c) Your score on this question is: 10.00 Feedback: 6. DML is used to (a) manipulate the structure of database applications. (b) add/modify/delete data in the database. (c) specify the structure of a database. (d) add and delete tables. Correct answer is (b) Your score on this question is: 10.00 Feedback: 7. DDL is used to (a) specify the structure of a database. (b) add contents to tables. (c) access the contents of tables. (d) define the structure of database applications. Correct answer is (a) Your score on this question is: 10.00 Feedback: 8. Which of the following SQL statements can be used to create a relational table? (a) APPEND (b) CREATE (c) ADD (d) INSERT Correct answer is (b) Your score on this question is: 10.00 Feedback: 9. Which of the following SQL statements can be used to modify just one row (out of many rows) in a table? (a) CHANGE (b) UPDATE (c) ALTER (d) MODIFY Correct answer is (b) Your score on this question is: 0.00 Feedback: 10. The term query by example refers to (a) a visual query language developed by IBM (b) a query for SQL examples (c) example SQL queries provided by the DBMS that users can modify to suit their current needs (d) example SQL queries provided by other users that can be modified to suit current needs Correct answer is (a) Your score on this question is: 10.00 Feedback: See section 1.2.3 in the course notes. Your performance was as follows: You took 4 minutes on this assessment from Wed Mar 29 08:46:41 UTC+0800 2006 to Wed Mar 29 08:50:36 UTC+0800 2006. Total score: 90.00 1. What information is necessary when specifying the structure of a table? (a) the name of the table, the names of the table's attributes, the data types of attributes, and the formats of attributes (b) the name of the table, the names of the table's attributes, the data types of the table's attributes, the formats of the table's attributes, and the maximum number of rows that the table can have (c) the name of the table and the names of the table's attributes (d) the name of the table and the amount of storage space to be allocated to the table Correct answer is (a) Your score on this question is: 0.00 Feedback: 2. The cardinality of a table is the number of _____ in the table. (a) columns (b) foreign keys (c) rows (d) keys Correct answer is (c) Your score on this question is: 10.00 Feedback: 3. The arity of a table is the number of _____ in the table. (a) foreign keys (b) keys (c) rows (d) columns Correct answer is (d) Your score on this question is: 10.00 Feedback: 4. The degree of a table is the number of _____ in the table. (a) rows (b) foreign keys (c) columns (d) keys Correct answer is (c) Your score on this question is: 10.00 Feedback: 5. A difference operation can be applied to tables that (a) are union compatible (b) have the same name (c) are the same size (d) have the same column names Correct answer is (a) Your score on this question is: 10.00 Feedback: 6. Which of the following SQL statements can be used to remove a row from a table? (a) DESTROY (b) DELETE (c) ERASE (d) REMOVE Correct answer is (b) Your score on this question is: 10.00 Feedback: 7. DML is used to (a) add/modify/delete data in the database. (b) add and delete tables. (c) manipulate the structure of database applications. (d) specify the structure of a database. Correct answer is (a) Your score on this question is: 10.00 Feedback: 8. A deletion operation will _____ if the deletion leads to the violation of a referential integrity constraint. (a) fail (b) succeed with warning (c) succeed without warning (d) crash the system Correct answer is (a) Your score on this question is: 10.00 Feedback: 9. DDL is used to (a) access the contents of tables. (b) add contents to tables. (c) define the structure of database applications. (d) specify the structure of a database. Correct answer is (d) Your score on this question is: 10.00 Feedback: 10. With Query By Example, a user enters a query by (a) writing an English description of the data that the user needs (b) typing a syntactically correct SQL query that uses column and table names similar to the correct column and table names in a database (c) filling in skeleton tables of the database with examples of what is to be retrieved (d) placing SQL keywords, such as select, under the column names they want to retrieve Correct answer is (c) Your score on this question is: 10.00 1. What information is necessary when specifying the structure of a table? (a) the name of the table, the names of the table's attributes, the data types of attributes, and the formats of attributes (b) the name of the table, the names of the table's attributes, the data types of the table's attributes, the formats of the table's attributes, and the maximum number of rows that the table can have (c) the name of the table and the names of the table's attributes (d) the name of the table and the amount of storage space to be allocated to the table Correct answer is (a) Your score on this question is: 0.00 Feedback: 2. The cardinality of a table is the number of _____ in the table. (a) columns (b) foreign keys (c) rows (d) keys Correct answer is (c) Your score on this question is: 10.00 Feedback: 3. The arity of a table is the number of _____ in the table. (a) foreign keys (b) keys (c) rows (d) columns Correct answer is (d) Your score on this question is: 10.00 Feedback: 4. The degree of a table is the number of _____ in the table. (a) rows (b) foreign keys (c) columns (d) keys Correct answer is (c) Your score on this question is: 10.00 Feedback: 5. A difference operation can be applied to tables that (a) are union compatible (b) have the same name (c) are the same size (d) have the same column names Correct answer is (a) Your score on this question is: 10.00 Feedback: 6. Which of the following SQL statements can be used to remove a row from a table? (a) DESTROY (b) DELETE (c) ERASE (d) REMOVE Correct answer is (b) Your score on this question is: 10.00 Feedback: 7. DML is used to (a) add/modify/delete data in the database. (b) add and delete tables. (c) manipulate the structure of database applications. (d) specify the structure of a database. Correct answer is (a) Your score on this question is: 10.00 Feedback: 8. A deletion operation will _____ if the deletion leads to the violation of a referential integrity constraint. (a) fail (b) succeed with warning (c) succeed without warning (d) crash the system Correct answer is (a) Your score on this question is: 10.00 Feedback: 9. DDL is used to (a) access the contents of tables. (b) add contents to tables. (c) define the structure of database applications. (d) specify the structure of a database. Correct answer is (d) Your score on this question is: 10.00 Feedback: 10. With Query By Example, a user enters a query by (a) writing an English description of the data that the user needs (b) typing a syntactically correct SQL query that uses column and table names similar to the correct column and table names in a database (c) filling in skeleton tables of the database with examples of what is to be retrieved (d) placing SQL keywords, such as select, under the column names they want to retrieve Correct answer is (c) The cardinality of a table is the number of _____ in the table. (a) rows (b) keys (c) foreign keys (d) columns Correct answer is (a) Your score on this question is: 10.00 Feedback: 2. The foreign key in a table T1 _____ the same _____ as the corresponding primary key in table T2. 1 must have, name 2 need not have, name 3 must have, domain (a) I and II (b) I, II, and III (c) II and III (d) I and III Correct answer is (c) Your score on this question is: 10.00 Feedback: 3. What information is necessary when specifying the structure of a table? (a) the name of the table and the names of the table's attributes (b) the name of the table, the names of the table's attributes, the data types of attributes, and the formats of attributes (c) the name of the table, the names of the table's attributes, the data types of the table's attributes, the formats of the table's attributes, and the maximum number of rows that the table can have (d) the name of the table and the amount of storage space to be allocated to the table Correct answer is (b) Your score on this question is: 10.00 Feedback: 4. The arity of a table is the number of _____ in the table. (a) columns (b) foreign keys (c) keys (d) rows Correct answer is (a) Your score on this question is: 10.00 Feedback: 5. A difference operation can be applied to tables that (a) are union compatible (b) are the same size (c) have the same name (d) have the same column names Correct answer is (a) Your score on this question is: 10.00 Feedback: 6. What can be specified in the selection condition of a SELECT statement? (a) a Boolean operation (b) an arithmetic operation (c) the conditions under which the statement should be executed (d) the time at which the selection should be performed Correct answer is (a) Your score on this question is: 0.00 Feedback: 7. The SQL clause to perform a set UNION operation is (a) MELD (b) UNION (c) UNITE (d) COMBINE Correct answer is (b) Your score on this question is: 10.00 Feedback: 8. Which of the following SQL statements can be used to add a row to a table? (a) APPEND (b) CREATE (c) ADD (d) INSERT Correct answer is (d) Your score on this question is: 10.00 Feedback: 9. A join operation joins _____ tables into _____. (a) two, one (b) four, two (c) three, one (d) three, two Correct answer is (a) Your score on this question is: 10.00 Feedback: 10. With Query By Example, a user enters a query by (a) placing SQL keywords, such as select, under the column names they want to retrieve (b) writing an English description of the data that the user needs (c) typing a syntactically correct SQL query that uses column and table names similar to the correct column and table names in a database (d) filling in skeleton tables of the database with examples of what is to be retrieved Correct answer is (d) Your score on this question is: 10.00 The degree of a table is the number of _____ in the table. (a) foreign keys (b) columns (c) rows (d) keys Correct answer is (b) Your score on this question is: 10.00 Feedback: 2. The arity of a table is the number of _____ in the table. (a) rows (b) keys (c) columns (d) foreign keys Correct answer is (c) Your score on this question is: 10.00 Feedback: 3. What information is necessary when specifying the structure of a table? (a) the name of the table and the amount of storage space to be allocated to the table (b) the name of the table and the names of the table's attributes (c) the name of the table, the names of the table's attributes, the data types of the table's attributes, the formats of the table's attributes, and the maximum number of rows that the table can have (d) the name of the table, the names of the table's attributes, the data types of attributes, and the formats of attributes Correct answer is (d) Your score on this question is: 10.00 Feedback: 4. The cardinality of a table is the number of _____ in the table. (a) foreign keys (b) columns (c) keys (d) rows Correct answer is (d) Your score on this question is: 10.00 Feedback: 5. DML is used to (a) specify the structure of a database. (b) add and delete tables. (c) manipulate the structure of database applications. (d) add/modify/delete data in the database. Correct answer is (d) Your score on this question is: 10.00 Feedback: 6. The SQL clause to perform a set UNION operation is (a) COMBINE (b) UNION (c) UNITE (d) MELD Correct answer is (b) Your score on this question is: 10.00 Feedback: 7. Which of the following SQL statements can be used to create a relational table? (a) ADD (b) APPEND (c) CREATE (d) INSERT Correct answer is (c) Your score on this question is: 10.00 Feedback: 8. DDL is used to (a) access the contents of tables. (b) specify the structure of a database. (c) add contents to tables. (d) define the structure of database applications. Correct answer is (b) Your score on this question is: 10.00 Feedback: 9. What can be specified in the selection condition of a SELECT statement? (a) the time at which the selection should be performed (b) an arithmetic operation (c) the conditions under which the statement should be executed (d) a Boolean operation Correct answer is (d) Your score on this question is: 10.00 Feedback: 10. The term query by example refers to (a) a query for SQL examples (b) example SQL queries provided by other users that can be modified to suit current needs (c) a visual query language developed by IBM (d) example SQL queries provided by the DBMS that users can modify to suit their current needs Correct answer is (c) Your score on this question is: 10.00 Feedback: See section 1.2.3 in the course notes. Go to top of assessment. Your performance was as follows: 1. What information is necessary when specifying the structure of a table? (a) the name of the table, the names of the table's attributes, the data types of attributes, and the formats of attributes (b) the name of the table and the amount of storage space to be allocated to the table (c) the name of the table and the names of the table's attributes (d) the name of the table, the names of the table's attributes, the data types of the table's attributes, the formats of the table's attributes, and the maximum number of rows that the table can have Correct answer is (a) Your score on this question is: 10.00 Feedback: (a) 2. The foreign key in a table T1 _____ the same _____ as the corresponding primary key in table T2. 1 must have, name 2 need not have, name 3 must have, domain (a) I and II (b) II and III (c) I and III (d) I, II, and III Correct answer is (b) Your score on this question is: 10.00 Feedback: (b) 3. The arity of a table is the number of _____ in the table. (a) foreign keys (b) rows (c) keys (d) columns Correct answer is (d) Your score on this question is: 10.00 Feedback: (d) 4. The cardinality of a table is the number of _____ in the table. (a) keys (b) columns (c) rows (d) foreign keys Correct answer is (c) Your score on this question is: 10.00 Feedback: (c) 5. Which of the following SQL statements can be used to create a relational table? (a) INSERT (b) ADD (c) CREATE (d) APPEND Correct answer is (c) Your score on this question is: 10.00 Feedback: (c) 6. The SQL clause to perform a set difference operation is (a) EXCEPT (b) OMIT (c) DIFFER (d) REJECT Correct answer is (a) Your score on this question is: 10.00 Feedback: (a) 7. Which of the following SQL statements can be used to remove a row from a table? (a) ERASE (b) REMOVE (c) DESTROY (d) DELETE Correct answer is (d) Your score on this question is: 10.00 Feedback: (d) 8. Which of the following SQL statements can be used to add a row to a table? (a) ADD (b) APPEND (c) CREATE (d) INSERT Correct answer is (d) Your score on this question is: 10.00 Feedback: (d) 9. What can be specified in the selection condition of a SELECT statement? (a) the time at which the selection should be performed (b) a Boolean operation (c) an arithmetic operat ...展开收缩

(系统自动生成,下载前可以参看下载内容)