Announcements • Reading for Monday – Appendix A • Homework 3 – Due today • Project: Steps 2. 1 -24 – Due 10/4 • Exam 1 – 10/6
Sample Queries on the STUDENT/FACULTY/TRANS Database 1. Find the ages of all students 2. Find all information on males transferees 3. Find all 21 year olds who are students or transferees 4. Find the ages of all students who have the same name as a faculty member.
Sample Queries on the STUDENT/FACULTY/TRANS Database 5. Find all possible student advisor pairs. List their names only. 6. Find all transferees who are the same age as the student named Beckman. 7. Find all faculty in Quincy's department.
Mapping Lecture 9
Views • External models in 3 -level architecture are called external views • Relational views are slightly different • Relational view is constructed from existing (base) tables • • • External model may have views and base tables
Mapping E-R Diagrams to Relations (Details pp. 206 -213) • Create a table for each entity type and each relationship. 1. Deal with strong entity types – area. Code first name pat. Id last number phone Patient DOB SSN
Mapping E-R Diagrams to Relations 2. Deal with weak entity types – date Visit visit. No 1 incurs M item Charge amount
Mapping E-R Diagrams to Relations 3. Deal with relationships – 1 to 1 – – 1 to N – – M-N–
Mapping E-R Diagrams to Relations 4. Deal with multi-valued attributes -