1. Prentice Hall © 2004 1 COS 346 Day 21

2. 7-2 Agenda Capstone Progress report due Assignment 9 not corrected yet Assignment 10 posted (last one!!!) –Due April 27 @ 2 PM –Lowest Assignment score will be dropped XML and ADO.NET on April 23 Quiz 3 on April 27 –SQL Chap 8-11 –DP Chaps 8, 9, 11, 12 and 13 –20 M/C @ 4 points each –4 short essays @ 5 points each –60 mins, Open book, Open notes Capstones Due on April 27 Discussion on Database Access Standards

3. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-3 David M. Kroenke’s Chapter Twelve: ODBC, OLE DB, ADO, and ASP Part One Database Processing: Fundamentals, Design, and Implementation

4. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-4 Introduction Because database applications today reside in a complicated environment, various standards have been developed for accessing database servers. Some of the important standards are –OBDC (Open Database Connectivity) is the early standard for relational databases. –OLE DB is Microsoft’s object-oriented interface for relational and other databases. –ADO (Active Data Objects) is Microsoft’s standard providing easier access to OLE DB data for the non-object-oriented programmer.

5. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-5 The Web Server Data Environment A Web server needs to publish applications that involve different data types.

6. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-6 The Role of the ODBC Standard

7. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-7 The Role of ODE DB

8. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-8 The Role of ADO

9. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-9 Open Database Connectivity (OBDC) The Open Database Connectivity (ODBC) standard provides a DBMS-independent means for processing relational database data. It was developed in the early 1990s by an industry committee and has been implemented by Microsoft and many other vendors. The goal is to allow a developer to create a single application that can access databases supported by different DBMS products without needing to be changed or recompiled.

10. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-10 ODBC Architecture

11. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-11 OBDC Components (Continued) OBDC consists of a data source, an application program, a driver manager, and a DBMS driver. A data source is the database and its associated DBMS, operating system, and network platform. –An ODBC data source can be a relational database, a file server, or a spreadsheet. An applications program issues requests to create a connection with a data source.

12. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-12 OBDC Components A driver manager determines the type of DBMS for a given ODBC data source and loads that driver in memory. A DBMS driver processes ODBC requests and submits specific SQL statements to a given type of data source. –A single-tier driver processes both ODBC calls and SQL statements. –A multiple-tier driver processes ODBC calls, but passes the SQL requests to the database server.

13. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-13 ODBC Driver Types: ODBC Single-Tier Driver

14. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-14 ODBC Driver Types: ODBC Multiple-Tier Driver

15. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-15 Conformance Levels Levels of conformance balance the scope of the OBDC standard. There are two types of conformance levels: –ODBC conformance levels concern the features and functions that are made available through the driver’s application program interface (API). A driver API is a set of functions that the application can call to receive services. –SQL conformance levels specify which SQL statements, expressions, and data types a driver can process.

16. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-16 Summary of OBDC Conformance Levels

17. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-17 Summary of OBDC Conformance Levels (Continued)

18. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-18 Summary of SQL Conformance Levels

19. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-19 Summary of SQL Conformance Levels (Continued)

20. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-20 ODBC Data Sources A data source is an ODBC data structure that identifies a database and the DBMS that processes it. Three types of data source names: –A file data source is a file that can be shared among database users having the same DBMS driver and privilege. –A system data source is local to a single computer and may be used by the operating system and any user on that system. System data sources are recommended for Web servers. To define a system data source name, the type of driver and the database need to be specified. –A user data source is available only to the user who created it.

21. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-21 Creating a System Data Source: Selecting the Oracle Driver

22. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-22 Creating a System Data Source: Setting Data Source Properties

23. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-23 David M. Kroenke’s Database Processing Fundamentals, Design, and Implementation (10 th Edition) End of Presentation: Chapter Twelve Part One

24. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-24 David M. Kroenke’s Chapter Twelve: ODBC, OLE DB, ADO, and ASP Part Two Database Processing: Fundamentals, Design, and Implementation

25. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-25 OLE DB OLE DB is an implementation of the Microsoft OLE object standard. –OLE DB objects are COM objects and support all required interfaces for such objects. OLE DB breaks the features and functions of a DBMS into COM objects, making it easier for vendors to implement portions of functionality. –This characteristic overcomes a major disadvantage of ODBC. –With ODBC, a vendor must create an ODBC driver for almost all DBMS features and functions in order to participate in ODBC at all.

26. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-26 Object-Oriented Concepts An object-oriented programming object is an abstraction that is defined by its properties and methods. –An abstraction is a generalization of something. –A property specifies set of characteristics of an object. –A method refers to actions that an object can perform. –A collection is an object that contains a group of other objects.

27. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-27 OLE DB Goals Create object interfaces for DBMS functionality pieces: –Query, update, transaction management, etc. Increase flexibility: –Allow data consumers to use only the objects they need. –Allow data providers to expose pieces of DBMS functionality. –Providers can deliver functionality in multiple interfaces. –Interfaces are standardized and extensible. Provide object interfaces over any type of data: –Relational and non-relational database, ODBC or native, VSAM and other files, Email, etc. Do not force data to be converted or moved from where it is.

28. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-28 OLE DB Basic Constructs There are data consumers and data providers: –Data consumers - Users of OLE DB functionality. –Data providers - Sources of OLE DB functionality. An interface is a set of objects and the properties and methods they expose in that interface: –Objects may expose different properties and methods in different interfaces. An implementation is how an object accomplishes its tasks: –Implementations are hidden from the outside world and may be changed without impacting the users of the objects.

29. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-29 OLE DB Terminology: Data Providers A rowset is equivalent to a cursor. OLE DB has two types of data providers: –Tabular data provider — exposes data via rowsets. Examples: DBMS, spreadsheets, ISAMs (file processors), email. –Service provider — a transformer of data through OLE DB interfaces. It is both a consumer and a provider of transformed data. Examples: query processors, XML document creator.

30. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-30 Rowset Interfaces

31. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-31 Active Data Objects (ADO) Active Data Objects (ADO) characteristics: –A simple object model for OLE DB data consumers –It can be used from VBScript, JScript, Visual Basic, Java, C#, C++ –It is a single Microsoft data access standard –Data access objects are the same for all types of OLE DB data

32. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-32 Invoking ADO from Active Server Pages In Microsoft’s Active Server Pages (ASP) are Web pages where: –Statements are enclosed within the characters. –ASP statements are processed on the Web server. –Other (HTML) statements are processed by the client Web browser.

33. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-33 The ADO Object Model

34. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-34 Connection Object A connection object establishes a connection to a data provider and data source. –Connections have an isolation mode. Once a connection is created, it can be used to create RecordSet and Command objects.

35. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-35 RecordSet Objects RecordSet objects represent cursors: –They have both CursorType and LockType properties. –RecordSets can be created with SQL statements. –The Fields collection of a RecordSet can be processed to individually manipulate fields. –The Errors collection contains one or more error messages that result from an ADO operation.

36. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-36 Command Object The command object is used to execute stored parameterized queries or stored procedures: –Input data can be sent to the correct ASP using the HTML FORM tag. –Table updates are made using the RecordSet Update method.

37. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-37 ADO Constants: Isolation Levels

38. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-38 ADO Constants: Cursor Levels

39. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-39 ADO Constants: Lock Types

40. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-40 Connection Object: ASP Code <% Dim objConn Set objConn = Server.CreateObject (“ADODB.connection”) objConn.IsolationLevel = adXactReadCommitted ‘ use ADOVBS objConn.Open “ViewRidgeSS”, %> <% objConn.Open “DSN=ViewRidgeOracle2;UID=DK1;PWD=Sesame” %> http://www.flb.fo/infolit/ADOVBS.INC

41. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-41 RecordSet Object: ASP Code <% Dim objRecordSet, varSql varSQL = “SELECT * FROM ARTIST” Set objRecordSet = Server.CreateObject(“ADODB.Recordset”) objRecordSet.CursorTye = adOpenStatic objRecordSet.LockType = adLockReadOnly objRecordSet.Open varSQL, objConn %>

42. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-42 Fields Collection: ASP Code <% Dim varI, varNumCols, objField varNumCols = objRecordSet.Fields.Count For varI = 0 to varNumCols - 1 Set objField = objRecordSet.Fields(varI) ‘ objField.Name now has the name of the field ‘ objField.Value now has the value of the field ‘ can do something with them here Next >%

43. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-43 Errors Collection: ASP Code <% Dim varI, varErrorCount, objError On Error Resume Next varErrorCount = objConn.Errors.Count If varErrorCount > 0 Then For varI = 0 to varErrorCount - 1 Set objError = objConn.Errors(varI) ‘ objError.Description contains ‘ a description of the error Next End If >%

44. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-44 Command Object: ASP Code <% Dim objCommand, objParam, objRs ‘Create the Command object, connect it to objConn and set its format Set objCommand = Server.CreateObject(“ADODB.command”) Set objCommand.ActiveConnection = objConn objCommand.CommandText=“{call FindArtist (?)}” ‘Set up the parameter with the necessary value Set objParam = objCommand.CreateParameter (“Nationality”, adChar, adParamInput, 25) objCommand.Parameters.Append objParam objParam.Value = “Spanish” ‘Fire the Stored Proc Set objRs = objCommand.Execute >%

45. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-45 ADO Example: Reading a Table Artist.asp

46. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-46 ADO Example: Reading a Table The Artist.asp Results

47. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall 12-47 David M. Kroenke’s Database Processing Fundamentals, Design, and Implementation (10 th Edition) End of Presentation: Chapter Twelve Part Two