CN102841783A

CN102841783A - Delphi-based three-layer database system implementation method

Info

Publication number: CN102841783A
Application number: CN2011101723381A
Authority: CN
Inventors: 杨际荣
Original assignee: ZHENJIANG HUAYANG INFORMATION TECHNOLOGY CO LTD
Current assignee: ZHENJIANG HUAYANG INFORMATION TECHNOLOGY CO LTD
Priority date: 2011-06-24
Filing date: 2011-06-24
Publication date: 2012-12-26

Abstract

The invention discloses a Delphi-based three-layer database system implementation method. With the development of middleware and Web technology, three-layer or multi-layer distributed application systems become more and more popular. The middleware, as the key technology of the distributed system applications, gives powerful impetus to various distributed applications based on own special advantages, and greatly boosts the development of integration of the application systems. The method is used for implementing a high-efficiency connection and operation for visiting the database information based on the three-layer structure of the Delphi middleware.

Description

A kind of implementation method of three layer data storehouse systems based on Delphi

Technical field

The present invention relates to the exploitation of database application system, through the distinctive database application of realization that can be efficient, safe based on the realization of the three layer data storehouse systems of Delphi.

Background technology

In the current database application system, be divided into two types by its structure, one type is the database application system of double-layer structure, and another kind of is the database application system of sandwich construction.The database application system of double-layer structure comprises client/server (C/S) pattern and browser/server (B/S) pattern, and its feature is that data are separated with program, the database server side management data; Client computer or browser display, visit and Update Information, therefore can develop respectively and safeguard, also reduced the workload of database server simultaneously; Reduced the flow of network, had stronger security, but when client-side program or browser more for a long time; The performance of server can obviously descend; And applied logic is installed on each client computer, if system will upgrade, just can only carry out one by one client computer; If client computer is distributed in different places, maintenance and upgrading task will be very heavy.In order to solve the deficiency of double-layer structure application system, people have proposed the tactic pattern of multi-layered database application system, and representative is three-decker.

Summary of the invention

To above deficiency, the objective of the invention is to propose a kind of implementation method of three layer data storehouse systems based on Delphi, be that a kind of standard engine ADO of the Microsoft of utilization access general data source operates.

Application server is a teledata module, and it is a COM program, and it is connected with database server with SQL statement through ADO.It is responsible for from the database server access data and through the DataSetProvider assembly data being divided into packet, is delivered to the client on the network through the DCOM agreement then.The assembly of client is responsible for restoring data, and this work is accomplished by DCOMConnection.The ClientDataSet assembly is a client data collection assembly; It is responsible for receiving the data that the reduction of DCOMConnection assembly is come; And give the client data processing components data transfer; Client data is handled and display module mainly contains ADOQuery, ADOTable, DataSource, DBGrid, DBEdit, DBComboBox or the like, and conversely, the ClientDataSet assembly is responsible for collecting the data of client process; And the data submission DCOMConnection assembly after handling, this assembly correctly writes database with data through DCOM agreement and application server.

Embodiment

At first set up application server programs and on forms, add ADOConnection1, ADOTable1, DataSource, four assemblies of DBGrid1, the attribute of these four assemblies is set.Preserve All Files, item file is called AppServer, and unit file is called Server1.A newly-built teledata module (RemoteData Module), type of setting is called rdstu, in its Uses clause, adds Server1, and the rdstu module just can have been visited the assembly of Server1 the inside like this.In module, add assembly DataSetProvider, the DataSet attribute that it is set is Form1.Table1, can local data be read on the dcom server like this, and offer client by the DataSetProvider assembly.Preserve unit file, called after Server2.

Next is a newly-built application program, on forms, adds assemblies such as DCOMConnection1, ClientDataSet1, DataSource1, DBGrid1, DBNavigator1.The ComputerName attribute that DCOMConnection1 is set is the computer name at server place, and program can be sought server on network like this, if book server then is not provided with the ComputerName attribute in the registration of this machine; The ServerName attribute that it is set is AppServer.rdstu; The Connected attribute is True, at this moment the activation server program.The RemoteServer attribute that ClientDataSet1 is set is DCOMConnection1; The ProviderName attribute is DataSetProvider1.ClientDataSet1 just can be through DCOMConnection1 from DataSetProvider1 assembly reading of data like this.The DataDet attribute of DataSource1 is set to ClientDataSet1.The DataSource attribute of DBGrid1 and DBNavigator1 is set to DataSource1.

Three layers of C/S structure have hardware system formation more flexibly, can select the hardware that adapts with its processing load and treatment characteristic for each layer.Reasonably cut apart three-decker and make it independent, can make the structure of system become simply clear, improved the maintainability of program.In three layers of C/S structure, each of application layer can concurrent development, and each layer also can be selected optimal separately development language, helps change and maintenance application technical manual.Make the processing logic of each program become very simple by layer dividing function.In Delphi, mainly realize through technology such as DataSnap.

Claims

1. implementation method based on the three layer data storehouse systems of Delphi: it is characterized in that application server is a teledata module, it is a COM program, and it is connected with database server with SQL statement through ADO.It is responsible for from the database server access data and through the DataSetProvider assembly data being divided into packet, is delivered to the client on the network through the DCOM agreement then.The assembly of client is responsible for restoring data, and this work is accomplished by DCOMConnection.

2. according to claim 1; Implementation method based on the three layer data storehouse systems of Delphi; It is characterized in that the ClientDataSet assembly is a client data collection assembly; It is responsible for receiving the data that the reduction of DCOMConnection assembly is come, and gives the client data processing components data transfer, and client data is handled and display module mainly contains ADOQuery, ADOTable, DataSource, DBGrid, DBEdit, DBComboBox or the like; Conversely; The ClientDataSet assembly is responsible for collecting the data of client process, and submits the data after handling to the DCOMConnection assembly, and this assembly correctly writes database with data through DCOM agreement and application server.