Melbourne Meeting – October 2015

Monday 19th October at 6 for 6:15pm start.

Client Server to Multi-Tier Architecture – Loc Nguyen

Loc is a long time Delphi database application developer who has worked with a few different databases including SQL Server using ADO Components.
Recent versions of Delphi make it easy to produce cross platform output but generally require using multi-tier architecture. Loc shared the experience in turning a C/S application into a 3 tier application with the help of a memory table (TClientDataSet) using a custom DataSet Provider.

  • Show a small database application using ADO components talking to SQL Server.
  • Uses TADOConnection, TADOQuery, TADOTable in TDataModule and TForms.
  • Explain how TClientDataSet replaces TADOQuery and TADOTable can make it easy to turn into multi tier application.
  • Explain how to TClientDataSet.Delta works and how to create a custom DataSet Provider. Also discuss briefly about why I rather use a custom data provider as oppose to using the TDataSetProvider recommended by EMBT.
  • Show how to write a server program using custom dataset provider and datasnap
  • Provide code examples of TClientDataSet replacing TADOQuery and TADOTables in the demo program.
  • Show the converted 3 tier application

Sample Code

A zipped file for the demonstration source is available here (16 MBytes). Note that “Spring Framework for Delphi ” is required to compile this code.