Firebird embedded error

[Raf20076]

Hi guys

I have a problem with firebird embedded. When I compile app I have got error

Code: Pascal  [Select][+][-]

1. Project project1 raised exception class 'EDatabaseError' with message
2. DataSource1: Circular datasource reference are not allowed

I tried everything and search the forum but I have no idea, what cause it.

My code is

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, DB, IBConnection, SQLDBLib, SQLDB, Forms,
9.   Controls, Graphics, Dialogs, DBCtrls, DBGrids, StdCtrls;
10.  
11. type
12.  
13.   { TForm1 }
14.  
15.   TForm1 = class(TForm)
16.     DataSource1: TDataSource;
17.     DBGrid1: TDBGrid;
18.     DBNavigator1: TDBNavigator;
19.     IBConnection1: TIBConnection;
20.     Label1: TLabel;
21.     SQLDBLibraryLoader1: TSQLDBLibraryLoader;
22.     SQLQuery1: TSQLQuery;
23.     SQLTransaction1: TSQLTransaction;
24.     procedure FormCreate(Sender: TObject);
25.    
26.   private
27.  
28.   public
29.  
30.   end;
31.  
32. var
33.   Form1: TForm1;
34.  
35. implementation
36.  
37. {$R *.lfm}
38.  
39. { TForm1 }
40.  
41. procedure TForm1.FormCreate(Sender: TObject);
42.  var
43.   DataPath:AnsiString;
44.   FirebirdPath: AnsiString;
45. begin
46.   DataSource1.DataSet := SQLQuery1;
47.  
48.   DataPath := ExtractFilePath(Application.ExeName) + 'data\employee.fdb'; // database
49.   FirebirdPath := ExtractFilePath(Application.ExeName) + 'firebird\fbclient.dll'; // database
50.  
51.   SQLDBLibraryLoader1.ConnectionType:='Firebird';
52.   SQLDBLibraryLoader1.LibraryName:=FirebirdPath;
53.   SQLDBLibraryLoader1.Enabled:=True;
54.  
55.   IBConnection1.DatabaseName:=DataPath;
56.   IBConnection1.Connected:=True;
57.  
58.  
59.  
60.   SQLQuery1.SQLConnection:=IBConnection1;
61.   SQLQuery1.SQL.Text:='select RDB$Relation_Name from RDB$RELATIONS where RDB$Relation_Name not like ''%$%''';
62.   SQLQuery1.Open;
63.   SQLQuery1.Active:=True;
64.   SQLTransaction1.DataBase:=IBConnection1;
65.   SQLQuery1.Transaction:=SQLTransaction1;
66.  
67.  
68.   DBNavigator1.DataSource := DataSource1;
69.   DBGrid1.DataSource := DataSource1;
70.  
71.  
72.  
73.  
74.  
75.  
76.  
77. end;
78.  
79.  
80. end.
81.  
82.  

Thanks

[Fenix0]

Hi guys

I have a problem with firebird embedded. When I compile app I have got error

Code: Pascal  [Select][+][-]

1. Project project1 raised exception class 'EDatabaseError' with message
2. DataSource1: Circular datasource reference are not allowed

I tried everything and search the forum but I have no idea, what cause it.

My code is

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, DB, IBConnection, SQLDBLib, SQLDB, Forms,
9.   Controls, Graphics, Dialogs, DBCtrls, DBGrids, StdCtrls;
10.  
11. type
12.  
13.   { TForm1 }
14.  
15.   TForm1 = class(TForm)
16.     DataSource1: TDataSource;
17.     DBGrid1: TDBGrid;
18.     DBNavigator1: TDBNavigator;
19.     IBConnection1: TIBConnection;
20.     Label1: TLabel;
21.     SQLDBLibraryLoader1: TSQLDBLibraryLoader;
22.     SQLQuery1: TSQLQuery;
23.     SQLTransaction1: TSQLTransaction;
24.     procedure FormCreate(Sender: TObject);
25.    
26.   private
27.  
28.   public
29.  
30.   end;
31.  
32. var
33.   Form1: TForm1;
34.  
35. implementation
36.  
37. {$R *.lfm}
38.  
39. { TForm1 }
40.  
41. procedure TForm1.FormCreate(Sender: TObject);
42.  var
43.   DataPath:AnsiString;
44.   FirebirdPath: AnsiString;
45. begin
46.   DataSource1.DataSet := SQLQuery1;
47.  
48.   DataPath := ExtractFilePath(Application.ExeName) + 'data\employee.fdb'; // database
49.   FirebirdPath := ExtractFilePath(Application.ExeName) + 'firebird\fbclient.dll'; // database
50.  
51.   SQLDBLibraryLoader1.ConnectionType:='Firebird';
52.   SQLDBLibraryLoader1.LibraryName:=FirebirdPath;
53.   SQLDBLibraryLoader1.Enabled:=True;
54.  
55.   IBConnection1.DatabaseName:=DataPath;
56.   IBConnection1.Connected:=True;
57.  
58.  
59.  
60.   SQLQuery1.SQLConnection:=IBConnection1;
61.   SQLQuery1.SQL.Text:='select RDB$Relation_Name from RDB$RELATIONS where RDB$Relation_Name not like ''%$%''';
62.   SQLQuery1.Open;
63.   SQLQuery1.Active:=True;
64.   SQLTransaction1.DataBase:=IBConnection1;
65.   SQLQuery1.Transaction:=SQLTransaction1;
66.  
67.  
68.   DBNavigator1.DataSource := DataSource1;
69.   DBGrid1.DataSource := DataSource1;
70.  
71.  
72.  
73.  
74.  
75.  
76.  
77. end;
78.  
79.  
80. end.
81.  
82.  

Thanks

The issue is that you're assigning `DataSource1.DataSet := SQLQuery1` before setting it to `DBNavigator1` and `DBGrid1`. To fix it, just change the order:

```pascal
SQLQuery1.Open;
DataSource1.DataSet := SQLQuery1;  // Set DataSource after opening the query
DBNavigator1.DataSource := DataSource1;
DBGrid1.DataSource := DataSource1;
```

This should solve the circular reference error.

[rvk]

You created the components vis the ide.
You could set all the connections the.

BUT are you sure you didn't set SQLQuery1.Datasource to Datasource1 in the Object Inspector?
That would mean you create a circular reference with the line DataSource1.DataSet := SQLQuery1

[Raf20076]

You created the components vis the ide.
You could set all the connections the.

BUT are you sure you didn't set SQLQuery1.Datasource to Datasource1 in the Object Inspector?
That would mean you create a circular reference with the line DataSource1.DataSet := SQLQuery1

Yes it was this problem plus I change code as

The issue is that you're assigning `DataSource1.DataSet := SQLQuery1` before setting it to `DBNavigator1` and `DBGrid1`. To fix it, just change the order:

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, DB, IBConnection, SQLDBLib, SQLDB, Forms,
9.   Controls, Graphics, Dialogs, DBCtrls, DBGrids, StdCtrls;
10.  
11. type
12.  
13.   { TForm1 }
14.  
15.   TForm1 = class(TForm)
16.     DataSource1: TDataSource;
17.     DBGrid1: TDBGrid;
18.     DBNavigator1: TDBNavigator;
19.     IBConnection1: TIBConnection;
20.     Label1: TLabel;
21.     SQLDBLibraryLoader1: TSQLDBLibraryLoader;
22.     SQLQuery1: TSQLQuery;
23.     SQLTransaction1: TSQLTransaction;
24.     procedure FormCreate(Sender: TObject);
25.  
26.   private
27.  
28.   public
29.  
30.   end;
31.  
32. var
33.   Form1: TForm1;
34.  
35. implementation
36.  
37. {$R *.lfm}
38.  
39. { TForm1 }
40.  
41. procedure TForm1.FormCreate(Sender: TObject);
42.  var
43.   DataPath:AnsiString;
44.   FirebirdPath: AnsiString;
45. begin
46.  
47.  
48.   DataPath := ExtractFilePath(Application.ExeName) + 'data\employee.fdb'; // database
49.   FirebirdPath := ExtractFilePath(Application.ExeName) + 'firebird\fbclient.dll'; // firebird dll's
50.  
51.   SQLDBLibraryLoader1.ConnectionType:='Firebird';
52.   SQLDBLibraryLoader1.LibraryName:=FirebirdPath;
53.   SQLDBLibraryLoader1.Enabled:=True;
54.  
55.   IBConnection1.DatabaseName:=DataPath;
56.   IBConnection1.Connected:=True;
57.  
58.  
59.   SQLTransaction1.DataBase:=IBConnection1;
60.  
61.   SQLQuery1.Transaction:=SQLTransaction1;
62.   SQLQuery1.SQLConnection:=IBConnection1;
63.   SQLQuery1.SQL.Text:='select RDB$Relation_Name from RDB$RELATIONS where RDB$Relation_Name not like ''%$%''';
64.   SQLQuery1.Open;
65.   SQLQuery1.Active:=True;
66.   DataSource1.DataSet := SQLQuery1;
67.   DBNavigator1.DataSource := DataSource1;
68.   DBGrid1.DataSource := DataSource1;
69.  
70.  
71.  
72.  
73.  
74.  
75.  
76.  
77.  
78.  
79.  
80.  
81. end;
82.  
83.  
84. end.
85.  
86.  

I don't know if this database is fully displayed?

[Raf20076]

I found good tutorial here
https://wiki.freepascal.org/SQLdb_Tutorial0
https://wiki.freepascal.org/SQLdb_Tutorial1
https://wiki.freepascal.org/SQLdb_Tutorial2
https://wiki.freepascal.org/SQLdb_Tutorial3
https://wiki.freepascal.org/SQLdb_Tutorial4

Thanks a lot

[Raf20076]

OK UPDATE IMPROVED VERSION

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, DB, IBConnection, SQLDBLib, SQLDB, Forms,
9.   Controls, Graphics, Dialogs, DBCtrls, DBGrids, StdCtrls;
10.  
11. type
12.  
13.   { TForm1 }
14.  
15.   TForm1 = class(TForm)
16.     DataSource1: TDataSource;
17.     DBGrid1: TDBGrid;
18.     DBNavigator1: TDBNavigator;
19.     IBConnection1: TIBConnection;
20.     Label1: TLabel;
21.     SQLDBLibraryLoader1: TSQLDBLibraryLoader;
22.     SQLQuery1: TSQLQuery;
23.     SQLTransaction1: TSQLTransaction;
24.     procedure FormCreate(Sender: TObject);
25.  
26.   private
27.  
28.   public
29.  
30.   end;
31.  
32. var
33.   Form1: TForm1;
34.  
35. implementation
36.  
37. {$R *.lfm}
38.  
39. { TForm1 }
40.  
41. procedure TForm1.FormCreate(Sender: TObject);
42.  var
43.   DataPath:AnsiString;
44.   FirebirdPath: AnsiString;
45. begin
46.  
47.  
48.   DataPath := ExtractFilePath(Application.ExeName) + 'data\employee.fdb'; // database
49.   FirebirdPath := ExtractFilePath(Application.ExeName) + 'firebird\fbclient.dll'; // firebird dll's
50.  
51.   SQLDBLibraryLoader1.ConnectionType:='Firebird';
52.   SQLDBLibraryLoader1.LibraryName:=FirebirdPath;
53.   SQLDBLibraryLoader1.Enabled:=True;
54.  
55.   IBConnection1.DatabaseName:=DataPath;
56.   IBConnection1.Connected:=True;
57.  
58.  
59.   SQLTransaction1.DataBase:=IBConnection1;
60.  
61.   SQLQuery1.Transaction:=SQLTransaction1;
62.   SQLQuery1.SQLConnection:=IBConnection1;
63.   SQLQuery1.SQL.Text:='select * from CUSTOMER'; //show only customers from database
64.   //Show all from database
65.   //SQLQuery1.SQL.Text:='select RDB$Relation_Name from RDB$RELATIONS where RDB$Relation_Name not like ''%$%''';
66.   SQLQuery1.Open;
67.   SQLQuery1.Active:=True;
68.   DataSource1.DataSet := SQLQuery1;
69.   DBNavigator1.DataSource := DataSource1;
70.   DBGrid1.DataSource := DataSource1;
71.  
72.  
73. end;
74.  
75.  
76. end.
77.  
78.