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(BQ) Part 2 book "Essentials of systems analysis and design" has contents: Designing the human interface, designing databases, systems implementation and operation, structuring system requirements - conceptual data modeling. | Find more at www.downloadslide.com seven Chapter Objectives © Corbis Structuring System Requirements: Conceptual Data Modeling After studying this chapter, you should be able to: ½ Concisely define each of the following key data-modeling terms: conceptual data model, entity-relationship diagram, entity type, entity instance, attribute, candidate key, multivalued attribute, relationship, degree, cardinality, and associative entity. ½ Ask the right kinds of questions to determine data requirements for an information system. ½ Draw an entity-relationship (E-R) diagram to represent common business situations. ½ Explain the role of conceptual data modeling in the overall analysis and design of an information system. 188 ½ Distinguish between unary, binary, and ternary relationships, and give an example of each. ½ Distinguish between a relationship and an associative entity, and use associative entities in a data model when appropriate. ½ Relate data modeling to process and logic modeling as different ways of describing an information system. ½ Generate at least three alternative design strategies for an information system. ½ Select the best design strategy using both qualitative and quantitative methods. Find more at www.downloadslide.com Chapter Preview . . . In Chapter 6 you learned how to model and an- captured during data modeling are crucial in alyze the flow of data (data in motion) between the design of databases, programs, computer manual or automated steps and how to show screens, and printed reports. For example, facts data stores (data at rest) in a data-flow diagram. such as these—a data element is numeric, a Data-flow diagrams show how, where, and when product can be in only one product line at a time, data are used or changed in an information sys- a line item on a customer order can never tem, but they do not show the definition, struc- be moved to another customer order—are all ture, and relationships within the data. .
