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DBST 652 – lecture 2

DBST 652 – lecture 2 . Lecture 2. DBST 652. Next slide reflects math set theory that is basis of relational databases. Entity Types and Member Entities. Elmasri, p. 66. “Car” Entity Type. { } - Multi-valued Attributes ( ) - Composite Attributes. Elmasri, p. 67.

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DBST 652 – lecture 2

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  1. DBST 652 – lecture 2 Lecture 2

  2. DBST 652 • Next slide reflects math set theory that is basis of relational databases

  3. Entity Types and Member Entities Elmasri, p. 66

  4. “Car” Entity Type { } - Multi-valued Attributes ( ) - Composite Attributes Elmasri, p. 67

  5. Multivalued Composite Attribute - “AddressPhone” {AddressPhone( {Phone(AreaCode,PhoneNumber)}, Address(StreetAddress(Number,Street,ApartmentNumber), City,State,Zip) ) Elmasri, p.65

  6. Preliminary Design of Entity Types for Company Database DEPARTMENT Name, Number, {Locations}, Manager, ManagerStartDate PROJECT Name, Number, Location, ControllingDepartment EMPLOYEE Name (FName, MInit, LName), SSN, Sex, Address, Salary, BirthDate, Department, Supervisor, {WorksOn (Project, Hours)} DEPENDENT Employee, DependentName, Sex, BirthDate, Relationship Elmasri, p. 69

  7. Look at book • As we step through next slides, keep book open to p. 62

  8. Instances of the WORKS_FOR Relationship Elmasri, p. 71

  9. Recursive Relationship - SUPERVISION Elmasri, p. 73

  10. 1:1 Relationship - MANAGES Elmasri, p. 74

  11. M:N Relationship - WORKS_ON Elmasri, p. 75

  12. ER Diagram Notation (1) Meaning Symbol Elmasri, p. 80

  13. ER Diagram Notation (2) Meaning Symbol Elmasri, p.80

  14. ER Diagram Notation Symbol Meaning R E1 E2 1 N R E2 E1 R E Elmasri, p. 80

  15. DBST 652 • Confused by participation • Does it work if total participation means “mandatory” and partial participation means “optional”? I think it does. • Mandatory requires at least one. • Optional allows zero rows.

  16. Look at p. 54 again • Look at ERD now - apply previous slides and be sure we understand notation • so…go to next slide and walk thru • confirm - if need be - p. 245

  17. ER Schema Diagram for COMPANY Database Elmasri, p.62

  18. Another way • Slight difference in notation - look at differences on next slide • But…says the same thing. That is, it is the same data model

  19. ER Diagram for COMPANY Schema Elmasri, p.83

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