Friday, September 16, 2016

Entity Relationship Modeling and ERDs

  • ·         Not dependent on the physical model. – Implementation-free
  • ·         A drawing that is used to represent a data model. – Entity Relationship Diagram

1. True or False: To be described as implementation-free, a data model must be changed to accommodate the database system onto which it is built. False
2. True or False: To be described as implementation-free, a data model must not change to accommodate the database system onto which it is built. True
3. List four goals of entity relationship modeling.
·         Capture all required information.
·         Ensure that information appears only once.
·         Model no information that is derivable from other information already modeled.
·         Locate information in predictable, logical place.
4. An __________ is a consistent tool that can be used to represent data requirements regardless of the type of database used. Entity Relationship Diagram

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