Data modeling is most often accomplished through the use of a(n) __________________. a. entity-relationship diagram b. data-flow diagram c. functional decomposition diagram d. activity diagram

A new sales ordering system needs a relational database that contains a customer table, a product inventory table, and an order table. Use a word-processing, graphics, or spread-sheet program to draw an entity-relationship diagram showing the relationships among these entities. Next, design each of these tables showing the keys and attributes to be included in each table. Include five sample records for each table.

Describe the guidelines for creating effective data-flow diagrams.