CODEWITHSUNDEEP
sqldelphiparametersproject
rajubhi
rajubhi

Reputation: 21

SQL Delphi "Parameter 'Subject' not found"

I have recently started to learn how to code in Delphi since moving from Python to do a project. I can't seem to find a fix to this issue. I have searched online for a couple of hours now and none of the 'fixes' seem to be working. I have tried using 'Query.ExecSQL', I have tried breaking the code up into segments, I have tried to assign edtSubject.Text to a variable and doing it that way, among a handful of other 'solutions' that haven't fixed the issue. I am really struggling with this and need a way to fix it that works quick, here is my code:

Query := TADOQuery.Create(Self);
Query.Connection := ADOConnection;
Query.SQL.Add('INSERT INTO tbl_RFI (Subject) VALUES (:Subject)');
Query.Parameters.ParamByName('Subject').Value := edtSubject.Text;
Query.ExecSQL;

I really hope that someone can help me with this, Thanks.

Upvotes: 2

Views: 4965

Answers (3)

Omid Golestan
Omid Golestan

Reputation: 71

Just add Query.ParamCheck := true before setting the SQl Text and it should be fine

Upvotes: 2

Jerry Irons
Jerry Irons

Reputation: 55

Late reply I know, but I just went through the same situation, so in case this helps someone else. And it happens at random, "parameter not found" during in my case a tadocommand. Program errors out, restart doing exactly same sequence of events and works fine. Load up compiler, step through and works just fine. Set a breakpoint, and I can see the parameter not defined. But again, it's not every time, it's kind of random.

So it feels like some type of timing issue. I tried the ParseSQL command, and that actually makes it error out every time with a different error. I think the command text was getting cropped but did not investigate this. (it's a fairly long command)

Anyway, it seems I was able to fix this by adding in an application.processmessages after my tadocommand is created and sql text assigned.

Upvotes: 1

Tony
Tony

Reputation: 838

Despite what others say I have had this same thing happen from time to time over the years in my production code.

Parameter 'ParameterName' not found

Always with ADO objects that were created in code. The best fix that I have found was here http://edn.embarcadero.com/article/20420

Basically just force the ADO object to reparse the parameters before you reference them.

EDIT: Thanks to Ken's feedback I have added a test first to check if the parameter exists before calling ParseSQL, thereby conserving the execution plan for the 99.9% of the time.

with TADODataSet.Create(nil) do
try
  Connection := MyADOConnection;
  CommandText := 'SELECT Foo ' +
    'FROM FooBar ' +
    'WHERE Bar = :Bar ';
  if Parameters.FindParam('Bar') = nil then
    Parameters.ParseSQL(CommandText, True); {<- THIS IS THE FIX }
  Parameters.ParamByName('Bar').Value := 'value';
  Open;
finally
  Free;
end;

Since adding the ParseSQL I haven't had the problem.

Upvotes: 1

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