1. Prentice Hall © 2004 1 COS 346 Day 19

2. 7-2 Agenda Questions? Assignment 8 not Corrected yet Assignment 9 posted –Due April 13 @ 2:05 PM Quiz 2 Corrected –2 A’s, 4 B’s & 2 C’s –There was a bad answer in the quiz New Time line Discussion on Managing Multiuser Databases

3. New time line April –9 - Managing Multiuser databases –13 - Managing Multiuser databases Assignment 9 due –16 - Database access standards April –20 - Database access standards Progress report –23 XML and ado.net Assignment 10 due –27 Quiz 3 Capstones Presentations Due

4. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-4 David M. Kroenke’s Chapter Nine: Managing Multiuser Databases Part Two Database Processing: Fundamentals, Design and Implementation

5. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-5 ACID Transactions Acronym ACID transaction is one that is Atomic, Consistent, Isolated, and Durable Atomic means either all or none of the database actions occur Durable means database committed changes are permanent

6. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-6 ACID Transactions Consistency means either statement level or transaction level consistency –Statement level consistency: each statement independently processes rows consistently –Transaction level consistency: all rows impacted by either of the SQL statements are protected from changes during the entire transaction With transaction level consistency, a transaction may not see its own changes

7. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-7 Consistent UPDATE CUSTOMER SET AreaCode = ‘834’ WHERE Zipcode = ‘04743’; BEGIN TRANSACTION; UPDATE CUSTOMER SET AreaCode = ‘834’ WHERE Zipcode = ‘04743; …some other stuff…. UPDATE CUSTOMER SET Discount= 0.05 WHERE AreaCode = ‘834’; …some other stuff…. COMMITT TRANSACTION

8. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-8 ACID Transactions Isolation means application programmers are able to declare the type of isolation level and to have the DBMS manage locks so as to achieve that level of isolation 3 Possible Problems –Dirty Reads  read uncommited data –Nonrepeatable Reads  if you reread data and find something has changed (committed change) –Phantom Reads  if you read data and find new row SQL-92 defines four transaction isolation levels: –Read uncommitted –Read committed –Repeatable read –Serializable

9. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-9 Transaction Isolation Level A Higher isolation level generally means lower throughput http://msdn.microsoft.com/en-us/library/ms173763.aspx USE AdventureWorks; GO SET TRANSACTION ISOLATION LEVEL REPEATABLE READ; GO BEGIN TRANSACTION; GO SELECT * FROM HumanResources.EmployeePayHistory; GO SELECT * FROM HumanResources.Department; GO COMMIT TRANSACTION; GO

10. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-10 Cursor Type A cursor is a pointer into a set of records It can be defined using SELECT statements Four cursor types –Forward only: the application can only move forward through the recordset –Scrollable cursors can be scrolled forward and backward through the recordset Static: processes a snapshot of the relation that was taken when the cursor was opened Keyset: combines some features of static cursors with some features of dynamic cursors Dynamic: a fully featured cursor Choosing appropriate isolation levels and cursor types is critical to database design http://www.sqlteam.com/article/cursors-an-overview http://msdn.microsoft.com/en-us/library/ms180169.aspx

11. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-11 Cursor Summary

12. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-12 Database Security Database security ensures that only authorized users can perform authorized activities at authorized times Developing database security –Determine users’ processing rights and responsibilities –Enforce security requirements using security features from both DBMS and application programs

13. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-13 DBMS Security DBMS products provide security facilities They limit certain actions on certain objects to certain users or groups (also called roles) Almost all DBMS products use some form of user name and password security

14. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-14 DBMS Security Model

15. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-15 DBMS Security Guidelines Run DBMS behind a firewall, but plan as though the firewall has been breached Apply the latest operating system and DBMS service packs and fixes Use the least functionality possible –Support the fewest network protocols possible –Delete unnecessary or unused system stored procedures –Disable default logins and guest users, if possible –Unless required, never allow all users to log on to the DBMS interactively Protect the computer that runs the DBMS –No user allowed to work at the computer that runs the DBMS –DBMS computer physically secured behind locked doors –Access to the room containing the DBMS computer should be recorded in a log

16. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-16 DBMS Security Guidelines Manage accounts and passwords –Use a low privilege user account for the DBMS service –Protect database accounts with strong passwords –Monitor failed login attempts –Frequently check group and role memberships –Audit accounts with null passwords –Assign accounts the lowest privileges possible –Limit DBA account privileges Planning –Develop a security plan for preventing and detecting security problems –Create procedures for security emergencies and practice them

17. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-17 Application Security If DBMS security features are inadequate, additional security code could be written in application program –Application security in Internet applications is often provided on the Web server computer However, you should use the DBMS security features first –The closer the security enforcement is to the data, the less chance there is for infiltration –DBMS security features are faster, cheaper, and probably result in higher quality results than developing your own

18. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-18 SQL Injection Attack SQL injection attack occurs when data from the user is used to modify a SQL statement User input that can modify a SQL statement must be carefully edited to ensure that only valid input has been received and that no additional SQL syntax has been entered Example: users are asked to enter their names into a Web form textbox –User input: Benjamin Franklin ' OR TRUE ' SELECT * FROM EMPLOYEE WHERE EMPLOYEE.Name = 'Benjamin Franklin' OR TRUE; –Result: every row of the EMPLOYEE table will be returned

19. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-19 Database Recovery In the event of system failure, that database must be restored to a usable state as soon as possible Two recovery techniques: –Recovery via reprocessing –Recovery via rollback/rollforward

20. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-20 Recovery via Reprocessing Recovery via reprocessing: the database goes back to a known point (database save) and reprocesses the workload from there through the existing apllications Unfeasible strategy because –The recovered system may never catch up if the computer is heavily scheduled –Asynchronous events, although concurrent transactions, may cause different results

21. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-21 Rollback/Rollforward Recovery via rollback/rollforward: –Periodically save the database and keep a database change log since the save Database log contains records of the data changes in chronological order When there is a failure, either rollback or rollforward is applied –Rollback: undo the erroneous changes made to the database and reprocess valid transactions –Rollforward: restored database using saved data and valid transactions since the last save

22. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-22 Rollback Before-image: a copy of every database record (or page) before it was changed.

23. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-23 Rollforward After-image: a copy of every database record (or page) after it was changed

24. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-24 Checkpoint A checkpoint is a point of synchronization between the database and the transaction log –DBMS refuses new requests, finishes processing outstanding requests, and writes its buffers to disk –The DBMS waits until the writing is successfully completed  the log and the database are synchronized Checkpoints speed up database recovery process –Database can be recovered using after-images since the last checkpoint –Checkpoint can be done several times per hour Most DBMS products automatically checkpoint themselves

25. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-25 Transaction Log

26. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-26 Database Recovery: A Processing Problem Occurs

27. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-27 Database Recovery: Recovery Processing

28. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-28 Managing the DBMS DBA’s Responsibilities –Generate database application performance reports –Investigate user performance complaints –Assess need for changes in database structure or application design –Modify database structure –Evaluate and implement new DBMS features –Tune the DBMS

29. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-29 Maintaining the Data Repository DBA is responsible for maintaining the data repository Data repositories are collections of metadata about users, databases, and its applications The repository may be –Virtual as it is composed of metadata from many different sources: DBMS, code libraries, Web page generation and editing tools, etc. –An integrated product from a CASE tool vendor or from other companies The best repositories are active and they are part of the system development process

30. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-30 David M. Kroenke’s Database Processing Fundamentals, Design, and Implementation (10 th Edition) End of Presentation: Chapter Nine Part Two

31. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-31 David M. Kroenke’s Chapter Eleven: Managing Databases with SQL Server 2000 Part One Database Processing: Fundamentals, Design, and Implementation

32. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-32 Introduction SQL Server 2000 can be installed on: –Windows 2000 and Windows XP workstations –Windows 2000 Server and Windows Server 2003 There are two ways to create database, to insert data, and to modify its structure: –Use the GUI SQL Server Enterprise Manager –Write SQL statements and submit them to SQL Server via the SQL Query Analyzer utility Many SQL Server professionals choose to create structures via SQL then modify them with the graphical tools For SQL Server 2005 use the GUI SQL Server Management Studio

33. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-33 View Ridge Gallery View Ridge Gallery is a small art gallery that has been in business for 30 years It sells contemporary European and North American fine art View Ridge has one owner, three salespeople, and two workers View Ridge owns all of the art that it sells; it holds no items on a consignment basis

34. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-34 Application Requirements View Ridge application requirements: –Track customers and their artist interests –Record gallery's purchases –Record customers' art purchases –List the artists and works that have appeared in the gallery –Report how fast an artist's works have sold and at what margin –Show current inventory in a Web page

35. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-35 View Ridge Gallery Database Design

36. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-36 The IDENTITY Keyword SQL Server supports the SQL-92 standard The IDENTITY keyword implements a new constraint for surrogate keys: –IDENTITY (m, n) creates a surrogate key with an Identity Seed of m and an Identity Increment of n: CREATE TABLE CUSTOMER( CustomerID int NOT NULL IDENTITY (1000,1), Name char(25)NOT NULL, CONSTRAINT CustomerPK RIMARY KEY (CustomerID), CONSTRAINT CustomerAK1 UNIQUE (Name) );

37. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-37 SQL Server Enterprise Manager Right-Click Databases, then use New Database… to create a new database

38. SQL Server Management Studio DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 8-38

39. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-39 Creating a Database Type in the new database name, and then click the OK button.

40. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-40

41. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-41 SQL Query Analyzer: Starting SQL Query Analyzer from Enterprise Manager Use the menu command Tools | SQL Query Analyzer.

42. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-42 SQL Query Analyzer: Creating the TRANS table in SQL Query Analyzer Use the Execute Query button after the SQL command is entered. Enter the SQL command in this window. Results appear in this window.

43. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-43 David M. Kroenke’s Database Processing Fundamentals, Design, and Implementation (10 th Edition) End of Presentation: Chapter Eleven Part One

44. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-44 David M. Kroenke’s Chapter Eleven: Managing Databases with SQL Server 2000 Part Two Database Processing: Fundamentals, Design, and Implementation

45. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-45 SQL Server CREATE TABLE Statements for the View Ridge Schema

46. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-46 SQL Server CREATE TABLE Statements for the View Ridge Schema

47. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-47 SQL Server CREATE TABLE Statements for the View Ridge Schema

48. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-48 SQL Server CREATE TABLE Statements for the View Ridge Schema

49. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-49 Viewing Tables in Enterprise Manager Right-Click the table name, then click Design Table to view table columns and properties.

50. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 8-50

51. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-51 Viewing Table Columns and Properties in Enterprise Manager Right-click the white space and then click Properties to see table constraints.

52. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-52 Viewing Table Constraints in Enterprise Manager

53. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-53 Creating a Relationship Diagram in Enterprise Manager Right-click Diagrams, then click New Database Diagram to create a relationships diagram.

54. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-54 Table Relationship Diagram Right-click a relationship line, then click Properties to see the properties.

55. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-55 WORK – TRANS Relationship Properties

56. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 8-56

57. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-57 Creating Views: By SQL in SQL Query Analyzer Do NOT put a semi-colon (;) at the end of a CREATE VIEW statement in SQL Query Analyzer!

58. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-58 Creating Views: By GUI in Enterprise Manager

59. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 8-59

60. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 9-60 David M. Kroenke’s Database Processing Fundamentals, Design, and Implementation (10 th Edition) End of Presentation: Chapter Eleven Part Two