ER Modeling Review

  1. Relatively simple representations of complex real world data structures
    Data models
  2. How to you determine the degree of a relationship
    The number of entities involved in the relationship
  3. How many instances of one entity can be involved with how many instances of another entity
  4. A detailed, logical representation of the data for an organization or business area expressed in terms of Entity Types, Relationships and Attributes
    ER Mode, ex. A CUSTOMER places an ORDER for a PRODUCT
  5. To be an attribute it must be
    A names property or characteristic of an entity type that is of interest to the organization
  6. Simple attribute
    Cannot be broken down into smaller components
  7. Composite attribute
    can be broken down into its component parts
  8. Attribute that can be derived from related attribute value
    Derived attribute
  9. Image Upload 1
    Unary - degree 1, also called bill of materials ore recursive
  10. Image Upload 2
    Binary, degree 2 most common
  11. Image Upload 3
    Ternary - degree 3
  12. An entity that associates one or more entity types and contains attributes that tie the two instances together
    Associative entity
  13. How do you reduce the number of entities
    If some entities have attributes in common we can generalize them into sets of entities, enhanced ER or EER
Card Set
ER Modeling Review