1. ADVANCED TOPICS IN RELATIONAL DATABASES Spring 2011 Instructor: Hassan Khosravi

2. 4.2 AUTHORIZATION

3. 4.3 Database Authorization Make sure users see only the data they are supposed to see. Guard the database against modifications by malicious users. Users have privileges Can only operate on data for which they are authorized Select on R Insert on R Update on R Delete on R

4. 4.4 Example Apply(dec), Select(Sid) Student select(SID,GPA)

5. 4.5

6. 4.6 How can we give the following privilege Select students info for Stanford applications only Delete Berkeley applications only

7. 4.7 Obtaining Privileges Relation creator is owner Owner has all privileges and may grant privileges Grant privs on R to users  [with grant option]

8. 4.8 Revoking Privileges Cascade: also revoke privileges granted from privileges being revoked transitively, unless also granted from another source Restrict: disallow if cascade would revoke any other privileges

9. 4.9 ON-LINE ANALYTICAL PROCESSING (OLAP)

10. 4.10 Two broad types of database activities OLTP: Online Transaction Processing  Short transactions  Simple queries  Touch small portion of data  Frequent updates OLAP: Online Analytical Processing  Long transactions  Complex queries  Touch large portions of data  Infrequent updates

11. 4.11 Data warehousing Bring data from operational OLPT sources into a single warehouse for OLAP analysis Decision Support System Data warehouse tuned for OLAP

12. 4.12 Star Schema Fact table (relationships) Updated frequently, very large  Sales transaction, course enrollment Dimension tables (entities, objects) Stores, items, customers Students, courses

13. 4.13 Example

14. 4.14 Performance Inherently very slow:  Special indexes  Extensive use of materialized views

15. 4.15 DATA CUBES

16. 4.16 Multi-dimensional OLAP Data Cube Dimension data form axes of Cube Fact data in cells Item Stores Customers

17. 4.17 Assuming one quantity for that Item Stores Customers Qty and price for I32, C4, s17

18. 4.18 Usually have defined aggregate functions that are meaningful Sum(qty * price) Item Stores Customers Aggregate over all items for C5, s11

19. 4.19 Usually have defined aggregate functions that are meaningful Sum(qty * price) Item Stores Customers Aggregate over all stores for I 61, C5, C21

20. 4.20 Usually have defined aggregate functions that are meaningful Sum(qty * price) Item Stores Customers Aggregate over all customers for I 5, s13

21. 4.21 Usually have defined aggregate functions that are meaningful Sum(qty * price) Item Stores Customers Aggregate over all customers and Items for s2 Aggregate over all stores and Items for c63 Aggregate over all stores and customers for I 52

22. 4.22 Usually have defined aggregate functions that are meaningful Sum(qty * price) Item Stores Customers Full aggregation

23. 4.23 Example

24. 4.24

25. 4.25 Drill Down Add for category to the group by and selection

26. 4.26 Roll Up