Database Management System and Data
Chapter 11:
Review Question: 1. Explain the main differences between a file processing system and a database system
ANS: Some main differences between a database management system and a file processing system are: * Both systems contain a collection of data and a set of programs which access that data. A DBMS coordinates both the physical and the logical access to the data, whereas a file-processing system coordinates only the physical access. * A DBMS reduces the amount of data duplication by ensuring that a physical piece of data is available to all programs authorized to have access to it, whereas data written by one program in a file-processing system may not be readable by another program. * A DBMS is designed to allow flexible access to data (i.e., queries), whereas a file-processing system is designed to allow pre-determined access to data (i.e., compiled programs). * A DBMS is designed to coordinate multiple users accessing the same data at the same time. A file-processing system is usually designed to allow one or more programs to access different data files at the same time. In a file-processing system, a file can be accessed by two programs concurrently only if both programs have read-only access to the file.
Discussion Topic: 2. Suggest three typical business situations where referential integrity avoids data problems.
ANS:
* In an inventory order system, you don't want an order to be deleted if there are inventory order items, or those items will be orphaned. * If you are assigning customers to a salesperson, referential integrity would make sure that a customer wasn't assigned to a salesperson that doesn't exist. * Payments in an accounting system should only be applied to an account, and if that account number changes, you want entries on that account to be updated as well.
Project:
1. Search the Internet to find information about data storage formats. Also do the research on international date formats.
Review Question: 1. Explain the main differences between a file processing system and a database system
ANS: Some main differences between a database management system and a file processing system are: * Both systems contain a collection of data and a set of programs which access that data. A DBMS coordinates both the physical and the logical access to the data, whereas a file-processing system coordinates only the physical access. * A DBMS reduces the amount of data duplication by ensuring that a physical piece of data is available to all programs authorized to have access to it, whereas data written by one program in a file-processing system may not be readable by another program. * A DBMS is designed to allow flexible access to data (i.e., queries), whereas a file-processing system is designed to allow pre-determined access to data (i.e., compiled programs). * A DBMS is designed to coordinate multiple users accessing the same data at the same time. A file-processing system is usually designed to allow one or more programs to access different data files at the same time. In a file-processing system, a file can be accessed by two programs concurrently only if both programs have read-only access to the file.
Discussion Topic: 2. Suggest three typical business situations where referential integrity avoids data problems.
ANS:
* In an inventory order system, you don't want an order to be deleted if there are inventory order items, or those items will be orphaned. * If you are assigning customers to a salesperson, referential integrity would make sure that a customer wasn't assigned to a salesperson that doesn't exist. * Payments in an accounting system should only be applied to an account, and if that account number changes, you want entries on that account to be updated as well.
Project:
1. Search the Internet to find information about data storage formats. Also do the research on international date formats.