Ch14 Database Design.docx

Chapter 14 Database Design True/False Questions 1. A file is a collection of similar records. Answer: True 2. A database is a collection of interrelated files. Answer: True 3. An historical advantage of using conventional files has been processing speed. They can be optimized for the access of the application. Answer: True 4. Duplication of data items in multiple files is normally cited as the principal disadvantage of file-based systems. Answer: True 5. A database is not necessarily dependent on the applications that use it. Answer: True 6. Given the large capacity disks that are now available, database administrators no longer have to be concerned about estimating how much disk capacity is required for a new database. Answer: False Rationale: It is still important for the database administrator to estimate how much disk capacity is required for a new database to ensure that sufficient disk space is available. One never knows how much of that space is already consumed by other applications and their data. 7. It is important for the database administrator to estimate how much disk capacity is required for a new database to ensure that sufficient disk space is available. Answer: True 8. Conventional files are relatively difficult to design and implement because they are normally designed for use with multiple applications or information systems. Answer: False Rationale: Conventional files are relatively easy to design and implement because they are normally designed for use with a single application or information system. 9. Files tend to be built around single applications without regard to other, future applications. Answer: True 10. A significant disadvantage of conventional files is their inflexibility and non-scalability. Answer: True 11. A significant advantage of conventional files is their flexibility and scalability. Answer: False Rationale: A significant disadvantage of conventional files is their inflexibility and non-scalability. 12. As legacy file-based systems and applications become candidates for reengineering, the trend is overwhelmingly in favor of replacing file-based systems and applications with database systems and applications. Answer: True 13. As enterprise systems and applications are re-engineered, the trend is overwhelmingly in favor of replacing database systems and applications with legacy file-based systems and applications. Answer: False Rationale: As legacy file-based systems and applications become candidates for reengineering, the trend is overwhelmingly in favor of replacing file-based systems and applications with database systems and applications. 14. The principal advantage of database systems is the ability to share the same data across multiple applications and systems. Answer: True 15. A principal advantage of the database approach is that you can build a single super-database that contains all data items of interest to an organization. Answer: False Rationale: A common misconception about the database approach is that you can build a single super-database that contains all data items of interest to an organization. This notion, however desirable, is not currently practical. 16. Most organizations build several databases, each one sharing data with several information systems. Thus, there will be some redundancy between databases. Answer: True 17. Most organizations build several databases leading to significant and uncontrolled redundancy between databases. Answer: False Rationale: Most organizations build several databases, each one sharing data with several information systems. Thus, there will be some redundancy between databases. However, this redundancy is both greatly reduced and ultimately, controlled. 18. Database technology offers the advantage of storing data in flexible formats. Answer: True 19. A disadvantage of database technology is the lack of flexibility in data storage formats. Answer: False Rationale: Database technology offers the advantage of storing data in flexible formats. 20. Data independence refers to the fact that databases are defined separately from the information systems and application programs that will use them. Answer: True 21. Database technology provides superior scalability, meaning that the database and the systems that use it can be grown or expanded to meet the changing needs of an organization. Answer: True 22. Database technology provides better technology for client/server and network computing architectures. Answer: True 23. You see a return to conventional file-based architectures today because they are better technology for client/server and network computing architectures. Answer: False Rationale: Database technology provides better technology for client/server and network computing architectures. 24. File technology is more complex than database technology. Answer: False Rationale: Database technology is more complex than file technology. 25. While a database management system (DBMS) is somewhat slower than file technology, these performance limitations are rapidly disappearing. Answer: True 26. The cost of developing databases is higher than the cost of developing files. Answer: True 27. A field is the physical implementation of a data attribute. Fields are the smallest unit of meaningful data to be stored in a file or database. Answer: True 28. A file is the physical implementation of a data attribute. Files are the smallest unit of meaningful data to be stored. Answer: False Rationale: A field is the physical implementation of a data attribute. Fields are the smallest unit of meaningful data to be stored in a file or database. 29. A primary key is a field whose values identify one and only one record in a file. Answer: True 30. A foreign key is a field whose values identify one and only one record in the same file. Answer: False Rationale: A primary key is a field whose values identify one and only one record in the same file. A foreign key is a pointer to the records of a different file in a database. 31. A secondary key is an alternate identifier for a database. Its value may identify either a single record or a subset of all records. Answer: True 32. A primary key might be created by combining two or more fields. In this situation, it is called a concatenated key. Answer: True 33. An index is frequently created for keys. Answer: True 34. Foreign keys are pointers to the records of a different file in a database. Answer: True 35. A descriptive field is any other non-key field that stores business data. Answer: True 36. A record is a collection of fields arranged in a predefined format. Answer: True 37. A field is a collection of records arranged in a predefined format. Answer: False Rationale: A record is a collection of fields arranged in a predefined format. 38. A blocking factor allows different records in the same file to have different lengths. Answer: False Page: 521-522 Rationale: A blocking factor is the number of logical records included in a single read or write operation. 39. Most database technologies impose a fixed-length record structure, meaning that each record instance has the same fields, same number of fields and same logical size. Answer: True 40. Some database systems can compress unused fields and values to conserve disk storage space. Answer: True Page: 551 41. Variable-length record structures allow different records in the same file to have different lengths. Answer: True 42. When a computer program "reads" a record from a database, it actually retrieves a group or block (or page.) of records at a time. This approach minimizes the number of actual disk accesses. Answer: True Page: 522 43. A variable-length record structure means that each record instance has the same fields, same number of fields and the same logical size. Answer: False Rationale: This describes a fixed length record structure. 44. A fixed-length record structure means that each record instance can have different fields, a different number of fields, as long as the length (size) of the record is always fixed at the same size. Answer: False Rationale: A fixed-length record structure means that each record instance has the same fields, same number of fields and the same logical size. 45. A blocking factor is the number of physical records included in a single read or write operation. Answer: False Page: 522 Rationale: A blocking factor is the number of logical records included in a single read or write operation. 46. The set of all occurrences of a given record structure in a database system is frequently called a table. Answer: True Page: 522 47. Master files or tables contain records that are relatively permanent. Thus, once a record has been added to a master file, it remains in the system indefinitely. The values of fields for the record will change over its lifetime, but the individual records are retained indefinitely. Answer: True Page: 522 48. Transaction files or tables contain records that describe business events. The data describing these events normally has a limited useful lifetime. Answer: True Page: 522 49. Document files and tables contain stored copies of historical data for easy retrieval and review without the overhead of regenerating the document. Answer: True Page: 522 50. Archival files and tables contain master and transaction file records that have been moved from on-line storage to off-line storage. Answer: True Page: 522 51. Table look-up files contain relatively static data that can be shared by applications to maintain consistency and improve performance. Answer: True Page: 522 52. Audit files are special records of updates to other files, especially master and transaction files. They are used in conjunction with archival files to recover "lost" data. Audit trails are typically built into better database technologies. Answer: True Page: 522 53. In today's database environment, the database technology itself usually predetermines and/or limits file organization for all tables contained in the database. Answer: True Page: 522 54. Many information systems shops hesitate to give end users access to operational databases for queries and reports. Answer: True 55. Data are a resource that must be controlled and managed! Answer: True 56. Prototyping is an alternative to doing database design. Answer: False Rationale: Prototyping is not an alternative to carefully thought-out database schemas. 57. Once a database design and its corresponding schema have been completed, a prototype database can usually be generated very quickly. Answer: True 58. Most modern database management systems (DBMS) include powerful, menu-driven database generators that automatically create a DDL and generate a prototype database from that DDL. Answer: True 59. The advantages and disadvantages of horizontal versus vertical distribution of data are similar. Answer: True 60. Centralization of the database refers to the physical distribution of entire tables to multiple locations on central processing units. Answer: False Page: 533 Rationale: Centralization of a database means that it would be implemented on a single server regardless of the number of physical locations that may require access to it. 61. Centralization is the simplest and easiest solution to maintain. Answer: True 62. Centralization helps data administrators maintain an important data management rule - data should be controlled and centralized as much as possible to ensure data integrity. Answer: False Rationale: Centralization violates a data management rule that has become important to many data administrators and users - data should be located as closely as possible to its users. 63. Central distribution of data refers to the physical duplication of entire tables to multiple locations. Answer: False Rationale: Replication of data refers to the physical duplication of entire tables to multiple locations. 64. Operational databases are developed to support day-to-day operations and business transaction processing for major information systems. Answer: True 65. Few high-end, enterprise database management systems include replication technology that coordinates updates to the duplicated tables and records to maintain data integrity. Answer: True Rationale: Most high-end, enterprise database management systems include replication technology that coordinates updates to the duplicated tables and records to maintain data integrity. 66. Replication of data offers performance and accessibility advantages and reduces network traffic, but it also increases the complexity of data integrity and requires more physical storage. Answer: True 67. Data warehouses store data extracted from the operational databases and conventional files. Answer: True 68. Operational databases and conventional files store data extracted from data warehouses. Answer: False Rationale: Data warehouses store data extracted from the operational databases and conventional files. 69. Data mining is the term used to describe the use query tools and decision support tools that are used to generate reports and analyses off of data warehouses. Answer: True 70. Metadata is the data about data, such as record and field definitions, synonyms, data relationships, validation rules, help messages, etc. Answer: True 71. DML commands may be "called" from programming languages. Answer: True 72. Contemporary data architecture allows for Internet-enabled database technology. Answer: True Page: 524 73. Examples of high-performance relational DBMSs include Oracle, IBM's DB2, and Microsoft Access. Answer: False Page: 528 Rationale: Examples of high-performance relational DBMSs include Oracle, IBM's DB2, and Microsoft's SQL Server. 74. A data administrator is responsible for the data planning, definition, architecture, and management. Answer: True Page: 524 75. One or more database administrators (DBAs) are responsible for the database technology, database design and construction consultation, security, backup and recovery, and performance tuning. Answer: True Page: 524 76. Database architecture refers to the database technology including the database engine, database utilities, database CASE tools for analysis and design, and database application development tools. Answer: True Page: 524 77. A database management system (DBMS) is specialized computer software available from computer vendors that is used to create, access, control, and manage the database. Answer: True 78. A data definition language (DDL) is used by the DBMS to physically establish record types, fields, and structural relationships. Additionally, the DDL defines views of the database. Answer: True 79. The data manipulation language (DML) is used by the DBMS to physically establish record types, fields, and structural relationships. Additionally, the DML defines views of the database. Answer: False Page: 525-526 Rationale: A data definition language (DDL) is used by the DBMS to physically record types, fields, and structural relationships. A data manipulation language (DML) is used to create, read, update, and delete records in the database and to navigate between different records and types of records. 80. The data definition language (DDL) is able to specify different views of a database. Views restrict the portion of the database that may be used or accessed by different users and programs. Answer: True 81. The data manipulation language (DML) is able to specify different views of a database. Views restrict the portion of the database that may be used or accessed by different users and programs. Answer: False Rationale: The data definition language (DDL) is able to specify different views of a database. Views restrict the portion of the database that may be used or accessed by different users and programs. 82. Most database management systems store both user data and metadata. Answer: True 83. Some metadata is stored in the actual database, while other metadata is stored in the CASE tool repositories. Answer: True 84. A data manipulation language (DML) is used to create, read, update, and delete records in the database and to navigate between different records and types of records. Answer: True 85. The data definition language (DDL) is used to create, read, update, and delete records in the database and to navigate between different records and types of records. Answer: False Page: 525-526 Rationale: A data definition language (DDL) is used by the DBMS to physically establish those record types, fields, and structural relationships. Additionally, the DDL defines views of the database. A data manipulation language (DML) is used to create, read, update, and delete records in the database and to navigate between different records and types of records. 86. The database engine of a DBMS responds to commands to create, read, update, and delete records in the database. Answer: True 87. In a relational database ach table (sometimes called a relation) consists of named columns (which are fields or attributes) and any number of unnamed rows (which correspond to records). Answer: True 88. A fundamental characteristic of SQL is that commands return a set of records. Answer: True 89. Relational databases implement data in a series of two-dimensional tables that are "related" to one another via foreign keys. Answer: True 90. The physical, relational database implementation of the data model is known as the schema. Answer: True 91. The physical, relational database implementation of the data model is known as the scenario. Answer: False Rationale: The physical, relational database implementation of the data model is known as the schema. 92. SQL is a language that supports complete database creation, maintenance and usage, and is the DDL and DML of most relational databases. Answer: True Page: 527 93. SQL provides a SELECT command to select specific records from a table based on specific criteria. Answer: True Page: 527 94. SQL provides a JOIN command to join two or more tables across a common field. Answer: True Page: 527 95. Triggers are programs embedded within a table that are automatically invoked by updates to another table. Answer: True Page: 528 96. Stored procedures are programs embedded within a table that can be called from an application program. Answer: True Page: 528 97. Triggers are programs embedded within a table that can be called from an application program. Answer: False Page: 528 Rationale: Triggers are programs embedded within a table that are automatically invoked by updates to another table. Stored procedures are programs embedded within a table that can be called from an application program. 98. Stored procedures are programs embedded within a table that are automatically invoked by updates to another table. Answer: False Page: 528 Rationale: Triggers are programs embedded within a table that are automatically invoked by updates to another table. Stored procedures are programs embedded within a table that can be called from an application program. 99. Both triggers and stored procedures are reusable because they are stored with the tables themselves (as metadata). Answer: True Page: 528 100. A good data model is simple. Answer: True 101. A good data model is complex. As a general rule, the data attributes that describe an entity should describe all possible characteristics of that entity. Answer: False Rationale: A good data model is simple. As a general rule, the data attributes that describe an entity should describe only that entity. 102. A good data model is essentially non-redundant. This means that each data attribute, other than foreign keys, describes at most one entity. Answer: True 103. Database design should proceed only if the underlying logical data model is in at least 2NF. Answer: False Rationale: Database design should proceed only if the underlying logical data model is in at least 3NF. 104. A good data model should be flexible and adaptable to future needs. Answer: True 105. A role name is an alternate name for a foreign key that clearly distinguishes the purpose that the foreign key serves in the table. Answer: True 106. Data distribution analysis establishes which business locations need access to which logical data entities and attributes. Answer: True 107. Centralization of a database means that it would be implemented on a single server regardless of the number of physical locations that may require access to it. Answer: True 108. Horizontal distribution of the data means that each table or entire rows in a table would be assigned to different database servers and locations. Answer: True 109. Vertical distribution of the data means that each table or entire rows in a table would be assigned to different database servers and locations. Answer: False Rationale: Horizontal distribution of the data means that each table or entire rows in a table would be assigned to different database servers and locations. 110. Vertical distribution of the data has specific columns of tables assigned to specific databases and servers. Answer: True 111. Horizontal distribution of the data has specific columns of tables assigned to specific databases and servers. Answer: False Rationale: Vertical distribution of the data has specific columns of tables assigned to specific databases and servers. 112. With horizontal distribution of data, the data cannot always be easily recombined for management analysis across sites. Answer: True 113. Many CASE tools can generate SQL code for creating a database from a CASE-based database schema. Answer: True 114. In implementing a database schema, each fundamental, associate, and weak entity is implemented as a separate table. Answer: True Page: 530 115. In implementing a database schema, an index should be created for any nonkey attributes that were identified as subsetting criteria requirements. Answer: True Page: 530 116. A database schema is the physical model or blueprint for a database. It represents the technical implementation of the logical data model. Answer: True Page: 530 117. In implementing a database schema, each supertype and subtype entity must be implemented with a separate table. Answer: False Page: 532 Rationale: Implementing them as separate tables is one of three options that can be employed. 118. Different DBMSs express precision of real numbers differently. Answer: True Page: 532 119. During the creation of database schemas, NULL means the field does not have to have a value; whereas, NOT NULL means the field must have a value. Answer: True Page: 532 120. During the creation of database schemas, NULL means the field must have a value; whereas, NOT NULL means the field must not have a value. Answer: False Page: 532 Rationale: During the creation of database schemas, NULL means the field does not have to have a value; whereas, NOT NULL means the field must have a value. 121. Key integrity for a database means that every table should have a primary key. Answer: True Page: 535 122. In a database, primary key fields may be duplicated across records. Answer: False Page: 535 Rationale: Key integrity for a database means that every table should have a primary key (which may be concatenated) but is controlled such that no two records in the table have the same primary key value. 123. The primary key for a record must never be allowed to have a NULL value. Answer: True Page: 535 124. The primary key for a record can have a NULL value. This defines a template record. Answer: False Page: 535 Rationale: The primary key for a record must never be allowed to have a NULL value. 125. Domain integrity means that appropriate controls must be designed to ensure that no field takes on a value that is outside the range of legal values. Answer: True 126. Domain integrity means that a primary key cannot take on the NULL value. Answer: False Rationale: Key integrity means that the primary key for a record must never be allowed to have a NULL value. Domain integrity means that appropriate controls must be designed to ensure that no field takes on a value that is outside the range of legal values. 127. Key integrity means that the primary key for a record must not take on a value that is outside the range of legal values. Answer: False Rationale: Key integrity means that the primary key for a record must never be allowed to have a NULL value. Domain integrity means that appropriate controls must be designed to ensure that no field takes on a value that is outside the range of legal values. 128. Referential integrity is the assurance that a foreign-key value in one table has a matching primary-key value in a related table. Answer: True 129. Referential integrity means that every table should have a unique, primary key, whose value is NOT NULL. Answer: False Rationale: Key integrity means that every table should have a primary key such that no two records in the table have the same primary key value. Referential integrity is the assurance that a foreign-key value in one table has a matching primary-key value in a related table. 130. A domain integrity error exists when a foreign key value in one table has no matching primary key value in the related table. Answer: False Rationale: A referential integrity error exists when a foreign key value in one table has no matching primary key value in the related table. 131. A referential integrity error exists when a foreign key value in one table has no matching primary key value in the related table. Answer: True 132. Horizontal distribution of data results in efficient access and security because each location has only those tables and rows required for that location. Answer: True Multiple Choice Questions 133. A Gender field can hold only the values M or F. This is an example of: A) key integrity B) domain integrity C) referential integrity D) logical integrity E) schema integrity Answer: B 134. The EmployeeID field in an employee table cannot be left blank. This is an example of: A) key integrity B) domain integrity C) referential integrity D) logical integrity E) schema integrity Answer: A Page: 535 135. The DeptID field in an employee table must match the DeptID of an existing record in the department table. This is an example of: A) key integrity B) domain integrity C) referential integrity D) logical integrity E) schema integrity Answer: C 136. Specialized computer software that is used to create, access, control, and manage the database is called: A) network system B) database management system C) operating system D) network operating system E) none of these Answer: B 137. A program embedded within a table and invoked automatically by updates is called a(n): A) DML B) DDL C) trigger D) stored procedure E) view Answer: C Page: 528 138. The person responsible for data planning, definition, architecture, and management is known as a(n): A) data administrator B) database administrator C) system owner D) end-user E) none of these Answer: A Page: 524 139. The person responsible for the database technology, database design and construction consultation, security, backup and recovery, and performance tuning is known as a(n): A) data administrator B) database administrator C) system owner D) end-user E) none of these Answer: B Page: 524 140. To add a new record to a database table you would use: A) DML B) DDL C) DBA D) CASE E) none of these Answer: A 141. Which language is used by the DBMS to physically establish those record types, fields, and structural relationships in a relational database? A) DML B) DDL C) DBA D) CASE E) none of these Answer: B 142. Which language is used by the DBMS to create, read, update, and delete records in the database and to navigate between different records and types of records? A) DML B) DDL C) CASE D) navigator E) none of these Answer: A 143. The physical, relational database implementation of a data model is known as a: A) scenario B) role model C) schema D) primary data model E) none of these Answer: C 144. Which of the following is not a command in SQL? A) SELECT B) BLOCK C) PROJECT D) JOIN E) all of these are commands in SQL Answer: B Page: 527 145. Which of the following is NOT a high-performance relational DBMS? A) Oracle B) IBM DB2 C) Microsoft SQL Server D) Microsoft Access E) Sybase Answer: D Page: 528 146. A program that is embedded within a relational database table that can be called from an application program is known as a(n): A) embedded procedure B) stored procedure C) trigger procedure D) schema procedure E) none of these Answer: B Page: 528 147. Which of the following are not criteria for producing a quality data model? A) A good data model is simple. B) A good data model is redundant. C) A good data model is flexible. D) A good data model is adaptable to future needs. E) all of these are criteria for producing a quality data model Answer: B 148. No two records in an employee table can have the same value for EmployeeID. This is an example of: A) key integrity B) domain integrity C) referential integrity D) logical integrity E) schema integrity Answer: A 149. Appropriate controls must be designed to ensure that no field takes on a value that is outside of the range of legal values. This refers to: A) referential integrity B) domain integrity C) key integrity D) data integrity E) none of these Answer: B 150. The foreign key value in one table must have a matching primary key value in the related table. This refers to: A) referential integrity B) domain integrity C) key integrity D) data integrity E) none of these Answer: A 151. The alternate name for a foreign key that clearly distinguishes the purpose that foreign key serves in the table is known as: A) role name B) attribute name C) service pointer D) domain name E) none of these Answer: A 152. When a database is implemented on a single server regardless of the number of physical locations that may require access to it is known as: A) centralization B) horizontal distribution C) vertical distribution D) replication E) none of these Answer: A 153. When a table or entire rows in a table are assigned to different database servers and locations, it is known as: A) centralization B) horizontal distribution C) vertical distribution D) replication E) none of these Answer: B 154. A collection of similar records is known as: A) a field B) a file C) a database D) an attribute E) none of these Answer: B 155. A collection of interrelated files is known as: A) a field B) a record C) a database D) a network E) none of these Answer: C 156. The physical implementation of a data attribute; it is the smallest unit of meaningful data to be stored: A) a field B) a file C) a record D) a key E) none of these Answer: A 157. The field whose values identify one and only one record in a file is known as the: A) attribute B) associative field C) primary key D) secondary key E) none of these Answer: C 158. An alternate identifier for a database, its value may identify either a single record or a subset of all records is known as a(n): A) attribute B) associative field C) primary key D) secondary key E) none of these Answer: D 159. Pointers to the records of a different file in a database, they are used to link records of one type to those of another type: A) attributes B) referential pointers C) descriptive fields D) foreign keys E) none of these Answer: D 160. A collection of fields arranged in a predefined format is known as a(n): A) attribute B) file C) concatenated key D) record E) none of these Answer: D 161. Record structures that require each record instance to have the same fields, same number of fields, and same logical size is classified as: A) a fixed length record structure B) a variable length record structure C) a table D) a transaction file structure E) none of these Answer: A 162. Record structures that allow different records in the same file to have different lengths is known as: A) a fixed length record structure B) a standard deviation record structure C) a variance record structure D) a variable length record structure E) none of these Answer: D 163. The number of logical records included in a single read or write operation from the computer's perspective is known as the: A) length factor B) transaction factor C) blocking factor D) referential factor E) none of these Answer: C Page: 522 164. The set of all occurrences of a record structure is known as a(n): A) field B) file C) object D) database E) none of these Answer: B Page: 522 165. The relational database equivalent of a file is known as a(n): A) scenario B) transaction C) block D) table E) none of these Answer: D Page: 522 166. Files or tables that contain records that are relatively permanent are known as: A) master B) transaction C) document D) archival E) none of these Answer: A Page: 522 167. Files or tables that contain records that describe business events are known as: A) master B) transaction C) document D) archival E) none of these Answer: B Page: 522 168. Files and tables that contain stored copies of historical data for easy retrieval and review without the overhead of regeneration are known as: A) master B) archival C) document D) table look-up E) none of these Answer: C Page: 522 169. Files and tables that contain master and transaction file records that have been deleted from on-line storage are known as: A) document B) table look-up C) archival D) audit E) none of these Answer: C Page: 522 170. Files that contain relatively static data that can be shared by applications to maintain consistency and improve performance are known as: A) document B) table look-up C) archival D) audit E) none of these Answer: B Page: 522 171. Files that are special records of updates to other files, especially master and transaction files, are known as: A) document B) audit C) archival D) block E) none of these Answer: B Page: 522 172. A database that stores data extracted from operational databases for the purpose of data mining is called a(n): A) transactional database B) personal database C) workgroup database D) data warehouse E) distributed database Answer: D 173. Which of the following is the smallest unit of data stored? A) file B) logical record C) block D) field E) none of these Answer: D 174. A collection of fields arranged in a predefined format is called a: A) character B) record C) field D) database E) none of these. Answer: B 175. Fields whose values identify one and only one record in a file are called: A) foreign keys B) primary keys C) alternative keys D) concatenated keys E) none of these Answer: B 176. Which of the following is an acceptable technique for implementing supertype/subtype entities? A) Each supertype and subtype can be implemented with a separate table. B) The subtypes may be collapsed into the supertype to create a single table. C) The supertype's attributes could be duplicated in a table for each subtype. D) A and C E) all of these Answer: E Page: 532 177. Which form of distribution duplicates data in multiple locations? A) centralization B) horizontal distribution C) vertical distribution D) replication E) none of these Answer: D 178. What is a blocking factor? A) size of a physical record B) size of a block of logical records C) number of logical records included in a single read D) number of physical records in a physical record E) size of a logical record Answer: C Page: 522 179. The main reason why data is retrieved in "blocks" is to: A) minimize the number of actual disk accesses B) save space C) make programming easier D) increase the lifetime of hardware E) all of these Answer: A Page: 522 180. The person responsible for the database technology, database design and construction, security, backup and recovery, and performance tuning is the: A) network administrator B) systems administrator C) systems analyst D) database administrator E) none of these Answer: D Page: 524 181. DDL stands for which of the following: A) data definition language B) data defined language C) driven data language D) driven data loop E) data definition lookup Answer: A 182. Which of the following languages is used to create, read, update, and delete records in the database and to navigate between different records and types of records? A) DML B) DDL C) DSS D) DDS E) none of these Answer: A 183. The database technology used to support data architecture is called: A) database architecture B) network architecture C) systems architecture D) data architecture E) none of these Answer: A Page: 524 184. An employee and a customer file are both examples of which type of file? A) master B) transaction C) scratch D) table E) archive Answer: A Page: 522 185. A file that contains records that describe business events is what type of file? A) master B) transaction C) scratch D) table E) archive Answer: B Page: 522 186. A file that contains off-line records of master or transaction files is what type of file? A) log B) scratch C) table D) archive E) none of these Answer: D Page: 522 187. When specific columns of tables are assigned to specific databases or servers, it is known as: A) centralization B) horizontal distribution C) vertical distribution D) replication E) none of these Answer: C 188. When entire tables are duplicated and stored in multiple locations or file servers, it is known as: A) centralization B) horizontal duplication C) vertical duplication D) replication E) none of these Answer: D 189. Which of the following is NOT a step of database capacity planning? A) Calculate the record size by summing the field sizes in each table. B) Calculate the table size by multiplying the record size times the number of records. C) Sum the table sizes. D) Optionally, add a slack capacity buffer. E) none of these Answer: E 190. Every nonkey field is called a(n): A) secondary key B) foreign key C) descriptive field D) record E) none of these Answer: C Fill in the Blank Questions 191. Database design should proceed only if the underlying logical data model is in at least _____________________ normal form. Answer: third 192. A(n) _____________________________ is the physical model or blueprint for a database. It represents the technical implementation of the logical data model. Answer: database schema Page: 530 193. During the creation of database schemas, _________________________ means the field does not have to have a value; whereas, __________________________ means the field must have a value. Answer: NULL, NOT NULL Page: 532 194. ____________________ integrity for a database means that every table should have a primary key (which may be concatenated) but is controlled such that no two records in the table have the same primary key value. Answer: Key Page: 535 195. The ______________________ key for a record must never be allowed to have a NULL value. Answer: primary Page: 535 196. ____________________________ integrity means that appropriate controls must be designed to ensure that no field takes on a value that is outside the range of legal values. Answer: Domain 197. _______________________________ integrity means that the architecture of relational databases implements the relationships between the records in tables via foreign keys. Answer: Referential 198. A(n) __________________________________ error exists when a foreign key value in one table has no matching primary key value in the related table. Answer: referential integrity 199. A(n) ________________________________ is an alternate name for a foreign key that clearly distinguishes the purpose that foreign key serves in the table. Answer: role name 200. _______________________________________ establishes which business locations need access to which logical data entities and attributes. Answer: Data distribution analysis 201. ____________________________________ of a database means that it would be implemented on a single server regardless of the number of physical locations that may require access to it. Answer: Centralization 202. ______________________________ distribution of the data means that each table or entire rows in a table would be assigned to different database servers and locations. This option results in efficient access and security because each location has only those tables and rows required for that location. Answer: Horizontal 203. _________________________________ distribution of the data has the unfortunate side effect that data cannot always be easily recombined for management analysis across sites. Answer: Horizontal or Vertical 204. ________________________________ distribution of the data has specific columns of tables assigned to specific databases and servers. Answer: Vertical 205. ___________________________________ of data refers to the physical duplication of entire tables to multiple locations. Answer: Replication 206. _________________________________ of data offers performance and accessibility advantages and reduces network traffic, but it also increases the complexity of data integrity and requires more physical storage. Answer: Replication 207. _______________________________ is the simplest and easiest solution to maintain; however, it violates a data management rule that has become important to many data administrators and users - data should be located as closely as possible to its users. Answer: Centralization 208. A(n) _____________________________ is a collection of similar records. Answer: file or table 209. A(n) ______________________________ is a collection of interrelated files. Answer: database 210. A historical ___________________________ (advantage or disadvantage) of using conventional files has been processing speed. They can be optimized for the access of the application. Answer: advantage 211. Duplication of data items in multiple files is normally cited as the principal disadvantage of (file-based or database) systems. Answer: file-based 212. _________________________________ is a three-step technique that places the data model into first normal form, second normal form and third normal form. Answer: Normalization 213. Once a database design and its corresponding schema have been completed, a _________________________ database can usually be generated very quickly. Answer: prototype 214. Conventional files are relatively __________________ (easy or hard) to design and implement because they are normally designed for use with a single application or information system. Answer: easy 215. The trend is overwhelmingly in favor of replacing file-based systems and applications with ______________ systems and applications. Answer: database 216. A significant disadvantage of ___________________ (conventional files or databases) is their inflexibility and non-scalability. Answer: conventional files 217. The principal sadvantage of ___________________ (conventional files or databases) is the ability to share the same data across multiple applications and systems. Answer: databases 218. Database technology provides superior ____________________, meaning that the database and the systems that use it can be grown or expanded to meet the changing needs of an organization. Answer: scalability 219. Realistically, most organizations build several databases, each one sharing data with several information systems. Thus, there will be some _____________ between databases. Answer: redundancy 220. A(n) __________________________ is the physical implementation of a data attribute. Answer: field 221. Database technology offers the advantage of storing data in flexible formats. This is made possible because databases are defined separately from the information systems and application programs that will use them. Theoretically, this allows us to use the data in ways not originally specified by end-users. This is known as ________________________________ (data dependence or data independence). Answer: data independence 222. Database technology is ______________________ (simpler or more complex) than file technology. Answer: more complex 223. A database management system (DBMS) is somewhat _____________ (slower or faster) than file technology. Answer: slower 224. A(n) __________________________ is the smallest unit of meaningful data to be stored in a file or database. Answer: field 225. A(n) _________________________ key is a field whose values identify one and only one record in a file. Answer: primary 226. A(n) ____________________________ key is an alternate identifier for a database. Its value may identify either a single record or a subset of all records. Answer: secondary 227. A primary key might be created by combining two or more fields. In this situation it is called a ___________________________ key. Answer: concatenated 228. A single file in a database may only have one _______________________ key, but it may have several ____________________________keys. Answer: primary, secondary 229. _________________________ keys are pointers to the records of a different file in a database. These keys are how the database links the records of one type to those of another type. Answer: Foreign 230. A(n) _______________________ is a collection of fields arranged in a predefined format. Answer: record 231. Most database technologies impose a(n) ________________________ record structure, meaning that each record instance has the same fields, same number of fields and same logical size. Answer: fixed-length 232. _________________________________ record structures allow different records in the same file to have different lengths. Answer: Variable-length 233. When a computer program "reads" a record from a database, it actually retrieves a group or ________________________ of records at a time. Answer: block or page. Page: 522 234. A(n) _______________________ factor is the number of logical records included in a single read or write operation (from the computer's perspective). Answer: blocking Page: 522 235. A(n) ______________________ is the set of all occurrences of a given record structure. In database systems, it is frequently called a table. Answer: file Page: 522 236. _________________________ files or tables contain records that are relatively permanent. Thus, once a record has been added, it remains in the system indefinitely. The values of fields for the record will change over its lifetime, but the individual records are retained indefinitely. Answer: Master Page: 522 237. _________________________ files or tables contain records that describe business events. The data describing these events normally has a limited useful lifetime. Subsequent to their useful lifetime, they are archived off-line. Answer: Transaction Page: 522 238. ________________________________ files and tables contain stored copies of historical data for easy retrieval and review without the overhead of regeneration. Answer: Document Page: 522 239. ___________________________ files and tables contain master and transaction file records that have been deleted from on-line storage. Thus, records are rarely deleted; they are merely moved from on-line storage to off-line storage. Their requirements are dictated by government regulation and the need for subsequent audit or analysis. Answer: Archival Page: 522 240. ______________________________________ files contain relatively static data that can be shared by applications to maintain consistency and improve performance. Answer: Table look-up Page: 522 241. _______________________ files are special records of updates to other files, especially master and transaction files. They are used in conjunction with archival files to recover "lost" data. Answer: Audit Page: 522 242. To facilitate searching and sorting, a(n) _________ is frequently created for keys. Answer: index 243. _________________________ is a resource that must be controlled and managed! Answer: Data 244. _______________________ tools are frequently capable of generating SQL code for the database from a CASE-based database schema Answer: CASE 245. A good data model should be _________________________ and adaptable to future needs. Answer: flexible 246. A business's ____________________ architecture defines how that business will develop and use both files and databases to store all of the organization's data, the file and database technology to be used, and the administrative structure set up to manage the data resource. Answer: data 247. __________________________________ databases are developed to support day-to-day operations and business transaction processing for major information systems. Answer: Operational or Transactional 248. Many information systems shops hesitate to give end-users access to operational databases for queries and reports. The volume of unscheduled reports and queries could overload the computers and hamper business operations that the databases were intended to support. That is why ___________________________________ are developed, possibly on separate computers to provide for end-users reports and queries. Answer: data warehouses 249. ___________________________ is the term used to describe the use of query tools and decision support tools used to generate reports and analyses off of data warehouses. Answer: Data mining 250. A(n) _______________________________________ is responsible for the data planning, definition, architecture, and management. Answer: data administrator Page: 524 251. One or more ____________________________________ are responsible for the database technology, database design and construction consultation, security, backup and recovery, and performance tuning. Answer: database administrators (DBAs) Page: 524 252. ____________________________________________ refers to the database technology including the database engine, database utilities, database CASE tools for analysis and design, and database application development tools. Answer: Database architecture Page: 524 253. A(n) ______________________________________________________ is specialized computer software available from computer vendors that is used to create, access, control, and manage the database. Answer: database management system (DBMS) 254. A(n) _____________________________ is used by the DBMS to physically establish those record types, fields, and structural relationships. Additionally, the DDL defines views of the database. Answer: data definition language (DDL) 255. The ______________________________ is able to specify different views of a database. Answer: data definition language (DDL) 256. _________________________________ is the data about the data, such as record and field definitions, synonyms, data relationships, validation rules, help messages, etc. Answer: Metadata 257. A(n) __________________________________ is used to create, read, update, and delete records in the database and to navigate between different records and types of records. Answer: data manipulation language (DML) 258. In general, the data manipulation language (DML) is very flexible in that it may be used by itself to create, read, update, and delete records; or its commands may be "called" from a separate host ___________________________. Answer: programming language 259. _________________________________ implement data in a series of two-dimensional tables that are "related" to one another via foreign keys. Each table consists of named columns (which are fields or attributes) and any number of unnamed rows (which correspond to records). Answer: Relational databases 260. The physical, relational database implementation of the data model is known as the __________________________________ . Answer: schema 261. ___________________ is a language, which supports complete database creation, maintenance and usage, and is the DDL and DML of most relational databases. Answer: SQL Page: 527 262. SQL allows you to __________________ two or more tables across a common field (a primary and a foreign key). Answer: JOIN Page: 527 263. ________________________________ are programs embedded within a table that are automatically invoked by updates to another table. Answer: Triggers Page: 528 264. ________________________________ are programs embedded within a table that can be called from an application program. Answer: Stored procedures Page: 528 265. Both triggers and stored procedures are reusable because they are stored with the tables themselves as_____________________. Answer: metadata Page: 528 266. A good data model is_______________________. As a general rule, the data attributes that describe an entity should describe only that entity. Answer: simple 267. A good data model is essentially___________________________. This means that each data attribute, other than foreign keys, describes at most one entity. Answer: non-redundant 268. ___________ restrict the portion of the database that may be used or accessed by different users and programs. Answer: Views