Tutorial: Implementing a FireDAC EMS Client Application

Go Up to EMS Client Application

You can create a client to connect to the EMS Server through the FireDAC Developer API that you previously set up using an EMS package.

This is a client sample application based on the resource created at Tutorial: Implementing a FireDAC EMS Resource.

Create a VCL application and add a TDataModule to the project:

• For Delphi

1. File > New > VCL Forms Application - Delphi.
2. On the Project Manager, right-click Add New > Other > New Items.
3. Go to Delphi Projects > Delphi Files > Data Module and click OK.

• For C++:

1. File > New > VCL Forms Application - C++Builder.
2. On the Project Manager, right-click Add New > Other > New Items.
3. Go to C++Builder Projects > C++Builder Files > Data Module and click OK.

On the TDataModule place the FireDAC components you need to proceed to the JSON data from the EMS Server.

Add the following components:

• A TFDGUIxWaitCursor component.
• A TFDSchemaAdapter component - to adapt the result of the JSON.
• Two TFDTableAdapter components - to adapt the content of the two tables.
  • In the DatSTableName property set the name of the TFDQueries from the TDataModule. For this tutorial, use QEmployee and QCustomers.
  • In the SchemaAdapter property set the name of the TFDSchemaAdapter.
• Two TFDMemTable components.
  • Set the names to mtEmployees and mtCustomers.
  • In the Adapter property set the name of the corresponding TFDTableAdapter.
  • Set the CachedUpdates property to True. You need to enable this option to update the info from the tables.
• Two TDataSource components.
  • In the DataSet property set the name of the corresponding TFDMemTable.

In the Client Form include the TDataModule in the implementation section:

• For Delphi:

implementation

{$R *.dfm}

uses Unit3;

• For C++ (In the Unit1.cpp file):

#include "Unit2.h"

Add the following components to the client form:

• Two TDBGrid components to show and update the data from the tables.
  • Set the DataSource property to the datasource in the TDataModule. This step is necessary to show the data on the grid.
• Two TButton components: one to get the data and the other to post the updates.
• A TEMSProvider component to set the configuration to the EMS Server.
  • Set the URLHost to the IP of the server, localhost by default.
  • Set the URLPort to the port of the server, 8080 by default.
• A TEMSFireDACClient to connect to the TFDSchemaAdapter from the client TDataModule.
  • Set the Provider property to the name of the TEMSProvider.
  • Set the Resource property to the name of the resource you want to access. For this tutorial, use FireDACTest.
  • Set the SchemaAdapter property to the name of the TFDSchemaAdapter from the TDataModule, for example ClientModule.FDSchemaAdapter2.
• A TActionList component to define actions to get and update the data.
  • Right-click and select Action List Editor....
  • Create two new actions and change the name property of the actions to ActionGetTables and ActionPostUpdates.
  • Double-click the OnExecute event handler of the actions to create the procedures.

Write the code for the GetTablesExecute procedure:

• For Delphi:

procedure TClientForm.ActionGetTablesExecute(Sender: TObject);
begin
  EMSFireDACClient1.GetData;
end;

• For C++ (In the Unit1.cpp file):

void __fastcall TForm1::ActionGetTablesExecute(TObject *Sender) {
	EMSFireDACClient1->GetData();
}

Write the code for the PostUpdatesExecute procedure:

• For Delphi:

procedure TClientForm.ActionPostUpdatesExecute(Sender: TObject);
begin
  EMSFireDACClient1.PostUpdates;
end;

• For C++ (In the Unit1.cpp file):

void __fastcall TForm1::ActionPostUpdatesExecute(TObject *Sender) {
	EMSFireDACClient1->PostUpdates();
}

• Define the Action property of the Get Tables button to ActionGetTables and the OnClick event handler to ActionGetTablesExecute.
• Define the Action property of the Post Updates button to ActionPostUpdates and the OnClick event handler to ActionPostUpdatesExecute.

Testing the New EMS FireDAC Application

To test your project on a developer environment, make sure that the FireDAC EMS Resource is running on your EMS Server.

1. To run your project, press F9 or choose Run > Run.
2. Click the ActionGetTables button to retrieve the data from the database.
3. Update any value and click ActionPostUpdates button to save the new data in the database.

See Also

• EMS Client Application
• Tutorial: Implementing a FireDAC EMS Resource