Hi,

I'm getting this: "operation cannot be performed on an inactive dataset".

Googling (I'm on a slow dialup on someone else's line) seems to indicate that the problem is with my Lazarus version.

The version I'm using is 0.9.23 beta SVN rev 12712.

I obviously can't download a new version of Lazarus...

Can anyone advise me?

Sorry,

I should have been more specific....

SQLQuery1.SQL.Text:='SELECT fname,
sname,id,comboboxcourse,studentnumber,enquirydate,enquiryreferencenumber
from registration WHERE fname=''Dave''';
  StringGrid1.RowCount:=2;
  SQLQuery1.SQL.Text:=sqlq;
  SQLQuery1.Open;
  SQLQuery1.First;
  while not SQLQuery1.EOF do
  begin
    StringGrid1.Cells[0,i]:=SQLQuery1.FieldByName('fname').AsString;
    StringGrid1.Cells[1,i]:=SQLQuery1.FieldByName('sname').AsString;
    StringGrid1.Cells[2,i]:=SQLQuery1.FieldByName('id').AsString;
    StringGrid1.Cells[3,i]:=SQLQuery1.FieldByName('comboboxcourse').AsString;
    StringGrid1.Cells[4,i]:=SQLQuery1.FieldByName('studentnumber').AsString;
    StringGrid1.Cells[5,i]:=SQLQuery1.FieldByName('enquirydate').AsString;
    RecNumber:=RecNumber+','+SQLQuery1.FieldByName('enquiryreferencenumber').AsString;
    inc(i);
    StringGrid1.RowCount:=i+1;
  end;
  SQLQuery1.Close;

Are you sure the query is closed at this point ?
If not, then you'll get this error.

Michael.

2008/5/28 Dave Coventry :

You forgot the line:
   SQLQuery1.Next;

end; SQLQuery1.Close;

Regards,
- Graeme -

_______________________________________________
fpGUI - a cross-platform Free Pascal GUI toolkit
http://opensoft.homeip.net/fpgui/

Graeme Geldenhuys wrote

You forgot the line: SQLQuery1.Next;

So I did!

However, putting it back in still gives me the same error.

As does explicitly using "SQLQuery.Close" prior to opening the Query. :(

Do you know at which line of your code the error occurs ? (add writeln()) statements or so...)

Michael.

A Clue!

Previously I had this code:

      SQLQuery1.SQL.Text:='SELECT enquiryreferencenumber FROM
registration WHERE fname='''+fname.Text+''' AND
sname='''+sname.Text+'''ORDER BY enquiryreferencenumber DESC LIMIT
1;';
      SQLQuery1.Open;
      enquiryreferencenumber.Text:=SQLQuery1.FieldByName('enquiryreferencenumber').AsString;
      SQLQuery1.Close;

Which raised an error saying that "enquiryreferencenumber" was not found. Then I added the line SQLQuery1.First; as listed below, which gave the Inactive Dataset error.

      SQLQuery1.SQL.Text:='SELECT enquiryreferencenumber FROM
registration WHERE fname='''+fname.Text+''' AND
sname='''+sname.Text+'''ORDER BY enquiryreferencenumber DESC LIMIT
1;';
      SQLQuery1.Open;
      SQLQuery1.First;
      enquiryreferencenumber.Text:=SQLQuery1.FieldByName('enquiryreferencenumber').AsString;
      SQLQuery1.Close;

Michael Van Canneyt wrote

Do you know at which line of your code the error occurs ? (add writeln()) statements or so...)

Hi Michael,

I put a breakpoint in and the error occurs when the code gets to "SQLQuery1.First;"

Seems like some internal error in sqldb code; At that point the dataset should already be open.

I think this is for Joost.

Michael.

Joost, Michael,

Will it take long to fix? (are we talking a quick patch, or three weeks work?)

I was supposed to demonstrate my app yesterday and had managed to get a bit of a dispensation because I was so close.

However, I think they will probably drop my project if I can't demonstrate it today....

Alternatively, is there another way of extracting the information?

Normally, it should already be fixed, but as I understood it, you can't upgrade ?

Can you try to get the (sql)db units from SVN ?
Or I can zip the lot and mail them to you if you prefer.

Michael.

If you go

   Query.Last;  // <<--- New line
   Query.First;

Does it give an error on the call to Last?

Graeme.

2008/5/28 Dave Coventry :

Yes.

The error is on last.

Michael, It would be very kind of you if you could email them to me as you offered.

I am, indeed on dialup, but the owner of the line has been very understanding and, if push came to shove, I could download fpc.

Many thanks!

Dave

Hi,

I'm not really sure if this is a c&p-error or the like, but ...

... here you assign another string named sqlq and overwrite the nice SQL from above.

Maybe that line is still in your code messing up the query?

HTH,
Marc

Hi!
I Pasted your code in my Lazarus' Text Editor....
I think the error is in the Query.
Try with:

 SQLQuery1.SQL.Text:='SELECT enquiryreferencenumber FROM
 registration WHERE fname=' + #39 + fname.Text+ #39 + ' AND
 sname=' + #39 +sname.Text+ #39 + ' ORDER BY enquiryreferencenumber DESC LIMIT
 1;';

On 28 May 2008 at 14:31, Dave Coventry wrote:

Marc,

Thanks very much for looking at the code. My fault, the above example is a cut and paste from the original code and my cutting knife must have slipped!

In any case, the SQLQuery1.SQL.Text is not overwirrten in my code. :)

2008/5/28 Juan Cort?s Cuesta :

Alternatively, use parameters in you query....

Query1.SQL.Text :=
   'SELECT fname,sname,id,comboboxcourse,' +
   '  studentnumber,'enquirydate,enquiryreferencenumber ' +
   'FROM registration ' +
   'WHERE fname=:fname';
Query1.ParamAsString['fname'] := 'Dave';

This removes the ugly double quotes and hash values etc...

Regards,
- Graeme -

_______________________________________________
fpGUI - a cross-platform Free Pascal GUI toolkit
http://opensoft.homeip.net/fpgui/

123555

Dave Coventry,

As does explicitly using "SQLQuery.Close" prior to opening the Query. :(

I suggest you use SQLQuery.Active := True (or False) instead of Open and Close.

Alternatively, is there another way of extracting the information?

If you don't need the db-aware visual controls you can use the libpq functions directly, they aren't hard to use. Some are:

PQconnectdb
PQstatus
PQexec
PQnfields
PQntuples
PQfname
PQgetvalue
PQclear
PQfinish
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Aaaaah.

I was uable to compile the fpc db libs but I managed to get access to a broadband connection and downloaded the daily snapshot.

Now I can't load my app into Lazarus:

2008/5/28 Jalal :

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Dave Coventry wrote

Aaaaah. I was uable to compile the fpc db libs but I managed to get access to a broadband connection and downloaded the daily snapshot.

I cannot help you, but what daily snapshot, there are several flavors: using fpc 2.2.0, 2.2.1 or 2.3.1?

Vincent

Okay, managed to find a previous copy of the Lazarus installer with fpc 2.2.1, Program working again,tried Jalal's sugestion using SQLQuery1.Active:=true, still l have the same error about inactive Dataset.:(

Next step, removed the Reference in the Datasource property of the SQLQuery. It Works!

Op donderdag 29-05-2008 om 10:21 uur [tijdzone +0200], schreef Dave Coventry:

Next step, removed the Reference in the Datasource property of the SQLQuery. It Works!

Duh.

That sounds logical. And I do aggree that this is very confusing. I already wanted to change that, but it's Delphi compatibility....

But maybe we can do something about that error message. Maybe we can detect this problem somewhat better....

Joost

I think that changing the error message to something like 'failed to open master datasource: '+E.Message
would be better.

Michael.