delphi 三层架构开发基本概念介绍（Delphi三层架构开发基本概念介绍）

1、delphi 三层架构开发基本概念介绍（Delphi三层架构开发基本概念介绍）Introduction to the basic concepts of Delphi three tier architecture developmentThree tier client / serverOne: advantages: flexibility and scalability.Reasons for applying three tier development technology (distributed)(Bibliography: Delphi 5.x distributed mult

2、i tier application system)One: to solve the client / server structure maintenance cost problem, improve the client / server structure scalability problem.The number of users supported by client / server structure has a certain limit (below 200 persons). The structure restricts the development of Int

3、ernet/Intranet and e-commerce. The three tier development uses Database Pooling, Object pooling, Resource Pooling, threading mode provides a high degree of scalability.Two: solve the problem of reuse of application logic.For example, when an enterprise wants to add Web browsing services to the origi

4、nal client / server structure, it is necessary to configure the Web server, rewrite all application logic, and update the MIS system. In the three-tier structure, COM/DCOM, CORBA (Common Object Request Broker Architecture) or Enterprise Java object, Bean, encapsulate business logic (called enterpris

5、e object), can solve the above problem. Greatly reduce the cost of development and maintenance.Three: the need to integrate different system structures, the need for timely application of new technologies.Two: the three tier service model of Microsoft1: structure: Windows DNA (Distributed Internet a

6、pplications, distributed intranets) COM (component object model, component object model) component as a tool to implement system and application services.L user serviceL serviceL data service(1) user services: Windows DNA defines four types of clients that can be used to implement user services:N st

7、andard browsing customers: rely on simple, page based HTML to manage data representation and user interaction. Its compatibility is good, not rich in function.The advantages of special browsers (ex: Dynamic HTML, scripts and ActiveX controls) to maximize the richness and functionality of user interf

8、aces are applicable to company intranetN dependent Internet clients: integrate access to the Internet and access to the operating system on the client machine.N enhanced Internet clients: Microsoft Office 97 and Microsoft Visual Studio.(2) business services: the integration of server based Microsoft

9、 products and customized COM component runtime environments.N Web services (Microfsoft Internet Information Server and Active Server Pages)N transaction and component services (Microsoft Transaction server and COM)N message service (Microsoft message queuing server).N general data access (universal

10、data access) (Microsoft data access)L mainframe environment interoperability (Microsoft SNA server). Its detailed information is listed in the following topics.(3) data service:N Microsoft SQL Server7 database.Catalogue and information base of n Microsoft Exchange server 5.5 version.Special topic:Bu

11、siness serviceOne: Web services (Microsoft Internet Information Server and Active Server Pages)Web service object model:1, the server object on the server to provide access to methods and properties. Example: Q (universal data (access) Microsoft data access component) setobjmyobject=server.createobj

12、ect (businessserver.myruleobject)2:Session object: the information required to store a particular user session.3:Application object: used to share the interest of all users of an application.4:Request object: slightly.5:Response object: slightlyTwo: transaction and component services (Microsoft Tran

13、saction server and COM)1:Microsoft transaction server (MTS) is a component based transaction processing system for complex transaction processing. MTS supports SQL, Server, and RenWhat is the XA protocol database based on the X/open algorithm (see note)?.The services provided by MTS are available:N

14、support for distributed transactions.N is used to control instantiation and use of object security services.Automatic management of N processes and threads.Management of N object instances.N database connection management (Lian Jiechi).In the application, you can declare the corresponding component

15、to complete the above services.2:MTS, like SQL server transactions, requires atomic execution, or whole success, as a whole failure. Transaction Server interacts with Microsoft Distributed Transaction Coordinator (MSDTC) to confirm that transactions satisfy ACID (atomicity, Atomicity, consistency, C

16、onsistency, separation, Isolatation, and durability Durability).The difference between 3:MTS and SQL server transactions can be encapsulated with visual basic, visual c+, and so on.MTSBusinessserver.myruleobject (universal data access) (Microsoft data access component) setobjmyobject=server.createob

17、ject ( )2:Session object: the information required to store a particular user session.3:Application object: used to share the interest of all users of an application.4:Request object: slightly.5:Response object: slightlyTwo: transaction and component services (Microsoft Transaction server and COM)1:

18、Microsoft transaction server (MTS) is a component based transaction processing system for complex transaction processing. MTS supports SQL, Server, and RenWhat is the XA protocol database based on the X/open algorithm (see note)?.The services provided by MTS are available:N support for distributed t

19、ransactions.N is used to control instantiation and use of object security services.Automatic management of N processes and threads.Management of N object instances.N database connection management (Lian Jiechi).In the application, you can declare the corresponding component to complete the above ser

20、vices.2:MTS, like SQL server transactions, requires atomic execution, or whole success, as a whole failure. Transaction Server interacts with Microsoft Distributed Transaction Coordinator (MSDTC) to confirm that transactions satisfy ACID (atomicity, Atomicity, consistency, Consistency, separation, I

21、solatation, and durability Durability).The difference between 3:MTS and SQL server transactions is that.MTS can be implemented with visual basic, visual c+ and other encapsulated MTS components, Recordset pairAdd a new line to the addnew method of the image. SQL server transactions can only be writt

22、en by Transact-SQL code, such as (ADO)4:Windows DNA (Windows distributed Internet Application Architecture): the strategy of developing customer / service model with web and togetherThe use of HTML, DHTML, Active server pages to provide users with the first layer (expression layer) and MTS component

23、, MTS, such as IIS (Internet information server), IIS/ASP component and ASP script to occupy the middle layer (business logic layer), SQL server as the data service layer.5:MTS uses the Distributed Transaction Coordinator (DTC) transaction engine.DTC to use the two level delivery standard.The inform

24、ation about DTC can be obtained by using the MMC (Microsoft Management Console) to open the c:winntsystem32services.msc,In the list on the right, find the DTC service and see its properties.6: uses MTS to maximize system performance.(note)N avoids passing or returning objects.N passes arguments as m

25、uch as possible through values (BY VAL). (By Val keyword minimize travel between networks)N avoids creating database cursors. Use less RecordSet objects.N enables MTS to execute concurrent client requests in multiple objects by making the object containment Threaded (Apartment).7:Note: XA is a two-p

26、hase commit protocol defined by the X/Open organization that allows transactions to be coordinated across multiple database services and sees it as a transaction. (Unix database, including Oracle, Informix, DB2 support)Three: Message Service (Microsoft message queuing server).1:Microsoft Message Que

27、ue (MSMQ Microsoft) provides asynchronous communication for applications.MSMQ is considered to be the bridge between the business and data services layer in distributed applications.2:MSMQ automatic integration with MTS. The application can encapsulate the MSMQ message in the MTS transaction.3:MSMQ

28、and Microsoft exchange server to provide users with different.Exchange (person -to -person) message. MSMQ provides application to application (application to -application) message.Four: universal data access (universal data access) (Microsoft data access component)The data access component spans the

29、 boundaries between the business service layer and the data service layer. ADO, OLE DB (embedded database) and ODBC together constitute the Microsoft data access component (MDAC)Five: Interoperability of mainframe environments (Microsoft SNA server)Microsoft COM &DCOM (brief introduction)One: COM is

30、 a protocol that defines how an object server interacts with an object client. Object server is a module to implement COM classes. Object consumer is a module that uses COM objects.DCOM extends the COM protocol so that the object server can be located on a computer that is different from the client.

31、 Calling object server through RPC. (CORBA is also a distributed object protocol)COM manages the security of objects through SSPI (Security Support Provider Interface, security support provider interface).Two: application server (intermediate layer) should have the characteristics:The ability of N r

32、emote boot, monitor and abort.N scalable capabilities.Lang=EN-USMTS component implementation, Recordset pairAdd a new line to the addnew method of the image. SQL server transactions can only be written by Transact-SQL code, such as (ADO)4:Windows DNA (Windows distributed Internet Application Archite

33、cture): the strategy of developing customer / service model with web and togetherThe use of HTML, DHTML, Active server pages to provide users with the first layer (expression layer) and MTS component, MTS, such as IIS (Internet information server), IIS/ASP component and ASP script to occupy the midd

34、le layer (business logic layer), SQL server as the data service layer.5:MTS uses the Distributed Transaction Coordinator (DTC) transaction engine.DTC to use the two level delivery standard.The information about DTC can be obtained by using the MMC (Microsoft Management Console) to open the c:winntsy

35、stem32services.msc,In the list on the right, find the DTC service and see its properties.6: uses MTS to maximize system performance. (note)N avoids passing or returning objects.N passes arguments as much as possible through values (BY VAL). (By Val keyword minimize travel between networks)N avoids c

36、reating database cursors. Use less RecordSet objects.N enables MTS to execute concurrent client requests in multiple objects by making the object containment Threaded (Apartment).7:Note: XA is a two-phase commit protocol defined by the X/Open organization that allows transactions to be coordinated a

37、cross multiple database services and sees it as a transaction. (Unix database, including Oracle, Informix, DB2 support)Three: Message Service (Microsoft message queuing server).1:Microsoft Message Queue (MSMQ Microsoft) provides asynchronous communication for applications.MSMQ is considered to be th

38、e bridge between the business and data services layer in distributed applications.2:MSMQ automatic integration with MTS. The application can encapsulate the MSMQ message in the MTS transaction.3:MSMQ and Microsoft exchange server to provide users with different.Exchange (person -to -person) message.

39、 MSMQ provides application to application (application to -application) message.Four: universal data access (universal data access) (Microsoft data access component)The data access component spans the boundaries between the business service layer and the data service layer. ADO, OLE DB (embedded dat

40、abase) and ODBC together constitute the Microsoft data access component (MDAC)Five: Interoperability of mainframe environments (Microsoft SNA server)Microsoft COM &DCOM (brief introduction)One: COM is a protocol that defines how an object server interacts with an object client. Object server is a mo

41、dule to implement COM classes. Object consumer is a module that uses COM objects.DCOM extends the COM protocol so that the object server can be located on a computer that is different from the client. Calling object server through RPC. (CORBA is also a distributed object protocol)COM manages the sec

42、urity of objects through SSPI (Security Support Provider Interface, security support provider interface).Two: application server (intermediate layer) should have the characteristics:The ability of N remote boot, monitor and abort.N scalable capabilities.The ability of n to configure easily.Ability t

43、o fail safely in n.The far layer start function: if the user wants to create a COM object on the remote computer. The DCOM service control manager on the remote machine (Service Control Manager, SCM) will automatically start the COM server and the COM objects available. Specific information can run

44、the DCOMCNFG command in the start menu.Ability: easy to configure in Windows Explorer right-click a COM DLL or EXE can activate or cancellation of registration.Scalable capabilities: scalable first level and second level. Two kinds of load balancing provided by DCOM. 1) static load balancing (specif

45、ying the running machine of the application server) can be specified in the attributes of the application in the DCOMCNFG. 2) dynamic load balancing, which is assigned by scheduler.Related technologies provided by Delphi:U COM / DCOM / COM+ enterprise object.U CORBA enterprise object.U XML / HTMLU C

46、GI / SAPI/NSAPIU ASPU Active X (Active Form)U ADO / OLE DBU BDE / IDAPI SQL LinksU MTS objectU MIDAS serverU CORBA server.Related components in 1) File menu, new Multitier and ActiveX page.2) in the component panel ADO, Midas, Internet, Express, ActiveX and other pages.Brief introduction of Corba1:

47、what is CORBA (Common Object Request Broker Architecture)?Corba is a distributed object standard structure defined by object manangement group (OMG). Language neutrality, using an object oriented design structure, allows software objects to be reused in different operating system platforms and appli

48、cations.If you want to implement the function, CORBA is a better solution:Heterogeneous platform and operating system should be integrated in L application system.The L application server must be executed in the linux/unix machine.L application system must perform critical tasks with fault tolerance

49、, strong safety must be stable and efficient.L wants to develop Internet/Intranet solutions that use Web objects.Future integration of L application system and Java.The structure of 2:corbaA CORBA object is a component that provides a specific service that declares services that can be provided by d

50、efining a set of output interfaces. In this output interface, the CORBA object defines the methods and access attributes that the client can call. The client only specifies the CORBA that provides the serviceSi-font-family: Times New Roman message queuing server.1:Microsoft Message Queue (MSMQ Micro

51、soft) provides asynchronous communication for applications.MSMQ is considered to be the bridge between the business and data services layer in distributed applications.2:MSMQ automatic integration with MTS. The application can encapsulate the MSMQ message in the MTS transaction.3:MSMQ and Microsoft

52、exchange server to provide users with different.Exchange (person -to -person) message. MSMQ provides application to application (application to -application) message.Four: universal data access (universal data access) (Microsoft data access component)The data access component spans the boundaries be

53、tween the business service layer and the data service layer. ADO, OLE DB (embedded database) and ODBC together constitute the Microsoft data access component (MDAC)Five: Interoperability of mainframe environments (Microsoft SNA server)Microsoft COM &DCOM (brief introduction)One: COM is a protocol th

54、at defines how an object server interacts with an object client. Object server is a module to implement COM classes. Object consumer is a module that uses COM objects.DCOM extends the COM protocol so that the object server can be located on a computer that is different from the client. Calling objec

55、t server through RPC. (CORBA is also a distributed object protocol)COM manages the security of objects through SSPI (Security Support Provider Interface, security support provider interface).Two: application server (intermediate layer) should have the characteristics:The ability of N remote boot, mo

56、nitor and abort.N scalable capabilities.The ability of n to configure easily.Ability to fail safely in n.The far layer start function: if the user wants to create a COM object on the remote computer. The DCOM service control manager on the remote machine (Service Control Manager, SCM) will automatic

57、ally start the COM server and the COM objects available. Specific information can run the DCOMCNFG command in the start menu.Ability: easy to configure in Windows Explorer right-click a COM DLL or EXE can activate or cancellation of registration.Scalable capabilities: scalable first level and second level. Two kinds of load balancing provided by DCOM. 1) static load balancing (specifying the running machine of the application server) can be specified in the