Typically, you use the BDE Configuration Utility BDECFG.EXE to create and configure aliases outside of Delphi. However, with the use of the TDatabase component, you have the ability to create and use this ALIAS within your application-- not pre-defined in the IDAPI.CFG.

The ability to create Aliases that are only available within your application is important. Aliases specify the location of database tables and connection parameters for database servers. Ultimately, you can gain the advantages of using ALIASES within your applications-- without having to worry about the existance of a configuration entry in the IDAPI.CFG when you deploy your application.

Summary of Examples:

Example #1:

Example #1 creates and configures an Alias to use STANDARD (.DB, .DBF) databases. The Alias is then used by a TTable component.

Example #2:

Example #2 creates and configures an Alias to use an INTERBASE database (.gdb). The Alias is then used by a TQuery component to join two tables of the database.

Example #3:

Example #3 creates and configures an Alias to use STANDARD (.DB, .DBF) databases. This example demonstrates how user input can be used to configure the Alias during run-time.

Example #1: Use of a .DB or .DBF database (STANDARD)

1. Create a New Project.
2. Place the following components on the form: - TDatabase, TTable, TDataSource, TDBGrid, and TButton.
3. Double-click on the TDatabase component or choose Database Editor from the TDatabase SpeedMenu to launch the Database Property editor.
4. Set the Database Name to 'MyNewAlias'. This name will serve as your ALIAS name used in the DatabaseName Property for dataset components such as TTable, TQuery, TStoredProc.
5. Select STANDARD as the Driveer Name.
6. Click on the Defaults Button. This will automatically add a PATH= in the Parameter Overrides section.
7. Set the PATH= to C:\DELPHI\DEMOS\DATA (PATH=C:\DELPHI\DEMOS\DATA)
8. Click the OK button to close the Database Dialog.
9. Set the TTable DatabaseName Property to 'MyNewAlias'.
10. Set the TDataSource's DataSet Property to 'Table1'.
11. Set the DBGrid's DataSource Property to 'DataSource1'.
12. Place the following code inside of the TButton's OnClick event.

        procedure TForm1.Button1Click(Sender: TObject);
        begin
              Table1.Tablename:= 'CUSTOMER';
              Table1.Active:= True;
        end;
    

13. Run the application.

    procedure TForm1.Button1Click(Sender: TObject);
    begin
          Database1.DatabaseName:= 'MyNewAlias';
          Database1.DriverName:= 'STANDARD';
          Database1.Params.Clear;
          Database1.Params.Add('PATH=C:\DELPHI\DEMOS\DATA');
          Table1.DatabaseName:= 'MyNewAlias';
          Table1.TableName:= 'CUSTOMER';
          Table1.Active:= True;
          DataSource1.DataSet:= Table1;
          DBGrid1.DataSource:= DataSource1;
    end;

1. Create a New Project.
2. Place the following components on the form: - TDatabase, TQuery, TDataSource, TDBGrid, and TButton.
3. Double-click on the TDatabase component or choose Database Editor from the TDatabase SpeedMenu to launch the Database Property editor.
4. Set the Database Name to 'MyNewAlias'. This name will serve as your ALIAS name used in the DatabaseName Property for dataset components such as TTable, TQuery, TStoredProc.
5. Select INTRBASE as the Driver Name.
6. Click on the Defaults Button. This will automatically add the following entries in the Parameter Overrides section.

   	SERVER NAME=IB_SERVEER:/PATH/DATABASE.GDB
   	USER NAME=MYNAME
   	OPEN MODE=READ/WRITE
   	SCHEMA CACHE SIZE=8
   	LANGDRIVER=
   	SQLQRYMODE=
   	SQLPASSTHRU MODE=NOT SHARED
   	SCHEMA CACHE TIME=-1
   	PASSWORD=
   

7. Set the following parameters

   	SERVER NAME=C:\IBLOCAL\EXAMPLES\EMPLOYEE.GDB
   	USER NAME=SYSDBA
   	OPEN MODE=READ/WRITE
   	SCHEMA CACHE SIZE=8
   	LANGDRIVER=
   	SQLQRYMODE=
   	SQLPASSTHRU MODE=NOT SHARED
   	SCHEMA CACHE TIME=-1
   	PASSWORD=masterkey
   

8. Set the TDatabase LoginPrompt Property to 'False'. If you supply the PASSWORD in the Parameter Overrides section and set the LoginPrompt to 'False', you will not be prompted for the password when connecting to the database. WARNING: If an incorrect password in entered in the Parameter Overrides section and LoginPrompt is set to 'False', you are not prompted by the Password dialog to re-enter a valid password.
9. Click the OK button to close the Database Dialog.
10. Set the TQuery DatabaseName Property to 'MyNewAliias'.
11. Set the TDataSource's DataSet Property to 'Query1'.
12. Set the DBGrid's DataSource Property to 'DataSource1'.
13. Place the following code inside of the TButton's OnClick event.

        procedure TForm1.Button1Click(Sender: TObject);
        begin
              Query1.SQL.Clear;
              Query1.SQL.ADD(
    		'SELECT DISTINCT * FROM CUSTOMER C, SALES S
    		WHERE (S.CUST_NO = C.CUST_NO)
    		ORDER BY C.CUST_NO, C.CUSTOMER');
              Query1.Active:= True;
        end;
    

14. Run the application.

This example brings up a input dialog and prompts the user to enter the directory to which the ALIAS is to be configured to.

The directory, servername, path, database name, and other neccessary Alias parameters can be read into the application from use of an input dialog or .INI file.

1. Follow the steps (1-11) in Example #1.
2. Place the following code inside of the TButton's OnClick event.

   procedure TForm1.Buttton1Click(Sender: TObject);
   var
     NewString: string;
     ClickedOK: Boolean;
   begin
     NewString := 'C:\';
     ClickedOK := InputQuery('Database Path', 
   	'Path: --> C:\DELPHI\DEMOS\DATA', NewString);
     if ClickedOK then
     begin
       Database1.DatabaseName:= 'MyNewAlias';
       Database1.DriverName:= 'STANDARD';
       Database1.Params.Clear;
       Database1.Params.Add('Path=' + NewString);
        Table1.DatabaseName:= 'MyNewAlias';
       Table1.TableName:= 'CUSTOMER';
       Table1.Active:= True;
       DataSource1.DataSet:= Table1;
       DBGrid1.DataSource:= DataSource1;
     end;
   end;
   

3. Run the Application.