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Passing parameters to ADODataSet

Posted on 2000-03-22
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Last Modified: 2012-06-27
I have a problem to retrieve the record from ADODataSet by changing its parameters:

Scenario:

ADODataSet of CommandType cmdStoredProc is connected to Access2000 query.
Query is a simple:
SELECT * FROM CLIENT WHERE CODE = [:INVALUE]

I open the query with:

with qryClient do begin
  Close;
  Parameters.Items[0].Value := sCode;
  Open;
  end;

When I assign value to the Parameters[0] of the dataset, everything works correct for the first time. However every subsequent assigning of parameter value does not locate the correct record.

i.e.
Calling for the first time with Code='A' the query retrieves 'Client A'
Calling next time with code='B' will still return 'Client A'

I realise that using 'locate' or 'filter' on full client query would be a solution, but in my case qryClient is required to hold only one record

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Comment
Question by:graga
  • 2
  • 2
5 Comments
 

Expert Comment

by:Borrt
ID: 2647288
ummmm im only new to delphi but have you tried resetting the variable before you run through the second time ?????
0
 

Expert Comment

by:Borrt
ID: 2647291
ummmm im only new to delphi but have you tried resetting the variable before you run through the second time ?????
0
 
LVL 13

Accepted Solution

by:
Epsylon earned 400 total points
ID: 2647297
I think you are handling the parameters wrong.

Adding a parameter:

var p: TParameter;

  p := ADODataSet1.Parameters.AddParameter;
  p.Name := 'INVALUE';
  p.Value := sCode;


Changing a parameter:

  ADODataSet1.Parameters.FindParam('INVALUE').Value := sCode;
0
 

Author Comment

by:graga
ID: 2647338
Epsylon,

Thanx again.
I just had to insert:

ADODataSet1.Parameters.Refresh

before your code and everything is working fine now.

0
 
LVL 13

Expert Comment

by:Epsylon
ID: 2647354
glad to hear that and thanks for the points graga

:o)
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