Содержание
- 2. * Yan Huang - ER ER 1976 proposed by Peter Chen ER diagram is widely used
- 3. * Yan Huang - ER Basic Concepts Entity set – an abstraction of similar things, e.g.
- 4. * Yan Huang - ER An Example
- 5. * Yan Huang - ER Relationship A relationship may be thought as a set as well
- 6. * Yan Huang - ER Relationship A relationship set is a mathematical relation among n ≥
- 7. * Yan Huang - ER Relationship Example
- 8. * Yan Huang - ER Attribute of A Relationship Set
- 9. * Yan Huang - ER Relationship The degree of a relationship = the number of entity
- 10. * Yan Huang - ER One-One and One-Many
- 11. * Yan Huang - ER Many-one and many-many
- 12. * Yan Huang - ER 1- many
- 13. * Yan Huang - ER Many - 1
- 14. * Yan Huang - ER Many - many
- 15. * Yan Huang -CSCE4350 - ER Alternative Cardinality Specification
- 16. * Yan Huang - ER Note on Mapping Cardinality Both many and 1 include 0 Meaning
- 17. * Yan Huang - ER Total Participation When we require all entities to participate in the
- 18. * Yan Huang - ER Self Relationship Sometimes entities in a entity set may relate to
- 19. * Yan Huang - ER More examples on self-relationship People to people Parent – children Manager
- 20. * Yan Huang 350 - ER Attributes Both entity sets and relationships can have attributes Attributes
- 21. * Yan Huang - ER Another Example
- 22. * Yan Huang - ER Keys A super key of an entity set is a set
- 23. * Yan Huang - ER Key Examples Suggest super keys for the following entity? What are
- 24. * Yan Huang - - ER Ternary Relationship
- 25. * Yan Huang - ER Can We Decompose a Ternary Relationship? Some relationships that appear to
- 26. * Yan Huang - ER Converting Ternary to binary In general, any non-binary relationship can be
- 27. * Yan Huang - ER Converting Ternary to binary
- 28. * Yan Huang - ER Design an ER Diagram Design a database for an on-line reservation
- 29. * Yan Huang - ER Weak Entity Set Some entity sets in real world naturally depend
- 30. * Yan Huang - ER Weak Entity Set Notations Double rectangles for weak entity set Double
- 31. * Yan Huang - ER Specialization A lower-level entity set inherits all the attributes and relationship
- 32. * Yan Huang - ER
- 33. * Yan Huang - ER Specification Disjoint Completeness constraint (use double lines) total : an entity
- 34. * Yan Huang - ER Design Considerations Use of entity sets vs. attributes Whether we want
- 35. * Yan Huang - ER Notations
- 36. * Yan Huang - ER Notations
- 37. * Yan Huang - ER ER Practice Again Design an ER diagram for an online music
- 38. * Yan Huang CE4350 - ER Best Practice Guide for ER Design Use of entity sets
- 39. * Yan Huang - ER ER for Banking Enterprise Description handhout
- 40. * Yan Huang - ER Read ER Diagrams Following are some ER diagrams grabbed from the
- 41. * Yan Huang - ER ? ? ? ? ? ? ? ? ?
- 42. * Yan Huang -CSCE4350 - ER ? ? ? ? ?
- 43. * Yan Huang -CSCE4350 - ER ?
- 45. Скачать презентацию