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CIS339 EOC Questions - Chapter 11

CIS339 EOC Questions - Chapter 11 - EOC Questions Chapter...

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EOC Questions Chapter 11 Systems Analysis and Design with UML Version 2.0 Chapter 11 DATA MANAGEMENT LAYER DESIGN 1. Describe the four steps to object persistence design. The four-step approach for object persistence design is: 1. Selecting the format of the storage 2. Mapping the problem domain objects to the object-persistence format 3. Optimizing the object-persistence format 4. Designing the data access and manipulation classes necessary to handle the communication between the system and the database. 2. How are a file and database different from each other? Files are essentially an electronic list of information that is formatted for a particular transaction. Any programs that are written must be developed to work with the file exactly as it is laid out. If there is a need to combine data in a new way, a new file must be created (usually by extracting data from other files) and a program written to work specifically with that new file. Databases, on the other hand, are made up of a collection of data sets that are related to each other in some way. Database management system software creates these data groupings. The DBMS provides access to the data and can usually provide access to any desired subset of data. It is not necessary to write new programs to build a new file in order to retrieve data from the database in a new way. 3. What is the difference between an end-user database and an enterprise database? Provide an example of each one. An end-user database is one that is designed to run on a PC and is used to create personal database applications. An end-user in sales might develop a Microsoft Access database, for example, to keep track of current and prospective client contacts. An enterprise database is one that is capable of handling huge volumes of information for the entire organization. Applications that serve the entire enterprise can be built upon these enterprise databases. These databases are fast, high capacity, but also complex. Oracle is a vendor of enterprise database management systems. 4. What are the differences between sequential and random access files? Sequential access files allow only sequential file operations to be performed because they actually store the data in sequence according to an identifier. These are very efficient when reports are needed for the whole set of data, but are quite inefficient in locating a specific object of interest. In contrast a random access Page 1
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EOC Questions Chapter 11 file is optimized for location of specific objects of interest but are less efficient for reports regarding the entire set of data. Generally, these are stored according to some formula or algorithm rather than based on the sequence of some identifier. 5. Name the five types of application files and describe the primary purpose of each file.
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CIS339 EOC Questions - Chapter 11 - EOC Questions Chapter...

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