Assignment 1 Solution

Chapter 1

Review Questions:

3. Contrast the following terms:

a. Data dependence; data independence. With data dependence, data descriptions are included with the application programs that use the data, while with data independence the data descriptions are separated from the application programs.

b. Structured data; unstructured data. Structured data is numeric, character, and dates data that is stored in tabular form. Unstructured data is multimedia data such as documents, maps, images, sound, etc.

c. Repository; database. A repository is a centralized storehouse for all data definitions, data relationships, and other system components, while a database is an organized collection of logically related data.

d. Entity; enterprise data model. An entity is an object or concept that is important to the business, while an enterprise data model is a graphical model that shows the high-level entities for the organization and the relationship among those entities.

e. Data warehouse; ERP system. Both use enterprise level data. Data warehouses store historical data at a chosen level of granularity or detail, and are used for data analysis purposes, to discover relationships and correlations about customers, products, and so forth that may be used in strategic decision making. ERP systems integrate operational data at the enterprise level, integrating all facets of the business, including marketing, production, sales, and so forth.

Problems and Exercises:

11.

a. structured data

b. metadata; fact describing property

c. unstructured data

d. unstructured data

Chapter 2

Review Questions:

1. Define each of the following key terms:

a. Information systems architecture (ISA). A conceptual blueprint or plan that expresses the desired future structure for the information systems in an organization.

b. Systems development life cycle (SDLC). A traditional methodology used to develop, maintain, and replace information systems.

c. Client/server architecture. A local area network-based environment in which database software on a server (called a database server or database engine) performs database commands sent to it from client workstations, and application programs on each client concentrate on user interface functions.

d. Incremental commitment. A strategy in systems development projects in which the project is reviewed after each phase and continuation of the project is rejustified in each of these reviews.

e. Enterprise data model. The first step in database development, in which the scope and general contents of organizational databases are specified.

f. Conceptual data model (or schema).. A detailed, technology-independent specification of the overall structure of organizational data.

g. Logical data model (or schema). The representation of data for a particular data management technology (such as the relational model.) In the case of a relational data model, elements include tables, columns, rows, primary and foreign keys as well as constraints.

h. Physical data model (or schema). A set of specifications that detail how data from a logical data model (or schema) are stored in a computer’s secondary memory for a specific database management system. There is one physical data model (or schema) for each logical data model.

Problems and Exercises:

10. Database development activities occur in each of the SDLC phases, and feedback may occur which causes a project to return to a prior phase. SDLC activities may find missing elements or errors when designing specific transactions, reports, displays, and inquiries. When a missing element is noticed, for example, it will be necessary to revisit the logical database design.

11. It is often said that conceptual data modeling is done in a top-down fashion, driven from a general understanding of the business area, not from specific information processing activities. Logical database design approaches database development from two perspectives. First, the conceptual data model is transformed into a standard notation through normalization, based on relational database theory. Then, as each computer program in the information system is designed, including the program’s input and output formats, a detailed review of the transactions, reports, displays, and inquiries supported by the database is performed. This bottom-up analysis verifies exactly what data are to be maintained in the database and the nature of those data as needed for each transaction, report, and so forth. During logical database design you combine, or integrate, the original conceptual data model (more general information) along with the individual user views (more specific information) into a comprehensive design.