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IS 4506 Database Connectivity

IS 4506 Database Connectivity. Overview. Two and Three-Tier C/S Architecture ASP Database Connection ODBC - Connection to DBMS Overview of transaction processing. Client /Server Architecture. PCs. Database Server. Middleware. Web Client/Server Architecture. Client Web Browser.

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IS 4506 Database Connectivity

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  1. IS 4506Database Connectivity

  2. Overview • Two and Three-Tier C/S Architecture • ASP Database Connection • ODBC - Connection to DBMS • Overview of transaction processing

  3. Client /Server Architecture PCs Database Server Middleware

  4. Web Client/Server Architecture Client Web Browser INTERNET INTRANET HTTP Server

  5. Multi-Tier Client/Server Architecture Client Web Browser INTERNET INTRANET Database Server HTTP Server

  6. ODBC Errors a) A user tries to connect to a database via your company’s web site and receives the error "ODBC…" Login failure. What is the possible cause? The user has insufficient permission to access the database. b) A user tries to connect to a database via your company’s web site and receives the error "ODBC…" General network error. What is the possible cause? Due to heavy use, the database was recently moved to another server.

  7. ODBC Errors c) A user tries to connect to a database via your company’s web site and receives the error "ODBC…" MS OLE ODBC provider for ODBC driver error 80004005. MS ODBC driver manager. Data source name not found and no default driver specified. What is the possible cause? Data source name is configured incorrectly. d) A user tries to connect to a database via your company’s web site and receives the error "ODBC…" Unable to find resources. What is the possible cause? ODBC driver not configured.

  8. ASP Code <%@ LANGUAGE = "VBSCRIPT"%> <% Set OBJdbConnection = Server.CreateObject("ADODB.Connection") OBJdbConnection.Open "is4506","", "” strSQL = "INSERT INTO Students (FName,LName,Email) VALUES ('" & Request.Form("first") & "', '" & Request.Form("last") & "','" & Request.Form("email") & "')" OBJdbConnection.Execute(strSQL) OBJdbConnection.Close %>

  9. Database Connection - Input Set OBJdbConnection = Server.CreateObject("ADODB.Connection") OBJdbConnection.Open "is4506","", "" strSQL = "INSERT INTO Students(fname,lname) VALUES ('" & Request.Form("fname") & "', '" & Request.Form("lname") & "')" OBJdbConnection.Execute(strSQL) OBJdbConnection.Close

  10. Database Connection - Update Set OBJdbConnection = Server.CreateObject("ADODB.Connection") OBJdbConnection.Open "is4506","", "" ifname = Request.Form("fname") 'example of using a variable in the SQL expression strSQL = "UPDATE Students SET fname = ('" & ifname & "'), lname = ('" & Request.Form("lname") & "') WHERE ID = (" & Request.Form("ID") & ")" OBJdbConnection.Execute(strSQL) OBJdbConnection.Close

  11. Database Connection - Delete Set OBJdbConnection = Server.CreateObject("ADODB.Connection") OBJdbConnection.Open "is4506","", "" 'Note that the single apostrophe is missing from the ID expression when using numbers vice strings. strSQL = "DELETE FROM Students WHERE ID = (" & Request.Form("ID") & ")" OBJdbConnection.Execute(strSQL) OBJdbConnection.Close

  12. Overview of Transaction Processing • Transaction • A unit of work that succeeds or fails as a whole • Method for coordinating a series of changes made to a resource or sets of resources • ACID Properties • Atomicity • Consistency • Isolation • Durability

  13. ACID Properties • Atomicity - Either all changes happen or none happen. • Consistency - Actions taken as a group do not violate any integrity. • Isolation - For actions that execute concurrently, one is either executed before or after the other, but not both. • Durability - Changes survive failures of process, network, operating system, and others.

  14. Three-Tier Architecture • Presentation • Business/Data components • Data access

  15. Components of a Transaction Client Network Receiver Queue Connections Context Security Configuration DB Manager Thread Pool Service Logic Synchronization Shared Data

  16. Four • Components • Account Modifies an account • Move Money Debit, credit, or transfer • Receipt Get unique # • Update receipt Allocation 100 receipt #s The Bank Example Transaction Transaction Account Account Update Receipt Move Money Receipt Client

  17. MSDE • MSDE is a stripped down version of SQL Server that is included with Access 2000 and Access 2002. • The Access 2000 version is named Microsoft Data Engine. It is a stripped down version of SQL Server 7. It can be installed directly from the Office 2000 CD from the following location: SQL\x86\SETUP\SETUPSQL.EXE • The Access 2002 version is named Microsoft Desktop Engine. It is a stripped down version of SQL Server 2000. It can also be installed directly from the CD from the following location: MSDE\SETUP.EXE • Both servers are fully functional SQL Servers but they do not include a user interface like Enterprise Manager.

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