Board index » delphi » TIBx Query no result on good query

2003-10-07 06:39:43 AM
delphi50
I am having great success in using TIBBlobStream, TIBSQL for executed
statements, and TIBQuery for updating blobs in fields taken from TIBTable
Locate commands. However, TIBQuery and TIBDataSet don't seem to return
meaningful results from a fairly simple SELECT query, and I am stymied. Can
anyone help?
Sample results and code follow. The TIBx database, transaction and query
were set up as described in the Help file "Getting started with InterBase
Express". The TQuery was set up to the database. The username and password
were entered once for the TIBx components, and again to access the TQuery
component.
Problem: TIBx routines are not returning a query result when querying a
database.
The same query done with TQuery works fine. What am I missing?
Execution of the following program results in a Memo1 display of:
IBTransaction1 No result:
SELECT * FROM PATENT WHERE PATENTNO = '5000001'
IBQuery1 No result:
SELECT * FROM PATENT WHERE PATENTNO = '5000001'
Got a result:
19022
//--------------------------------------------------------------------------
-
#include <vcl.h>
#pragma hdrstop
#include <ib.hpp>
#include <ibdatabase.hpp>
#include <ibtable.hpp>
#include <ibquery.hpp>
#include "QueryTestU.h"
//--------------------------------------------------------------------------
-
#pragma package(smart_init)
#pragma resource "*.dfm"
TQTest *QTest;
//--------------------------------------------------------------------------
-
__fastcall TQTest::TQTest(TComponent* Owner)
: TForm(Owner)
{
}
//--------------------------------------------------------------------------
-
void __fastcall TQTest::btnQueryClick(TObject *Sender)
{
AnsiString workstring;
workstring = "SELECT * FROM PATENT WHERE PATENTNO = '5000001'";
IBDatabase1->Connected = true;
IBDataSet1->Close();
IBDataSet1->SelectSQL->Clear();
IBDataSet1->SelectSQL->Add(workstring);
IBDataSet1->Prepare();
IBTransaction1->Active = true;
IBDataSet1->Open();
Memo1->Clear();
if (IBDataSet1->FindFirst())
{
Memo1->Lines->Add("Got a result:");
Memo1->Lines->Add(IntToStr(IBDataSet1->FieldByName("RECNO")->AsInteger));
}
else
{
Memo1->Lines->Add("IBTransaction1 No result:");
Memo1->Lines->Add(workstring);
}
IBDataSet1->Close();
IBTransaction1->Active = false;
IBQuery1->Close();
IBQuery1->SQL->Clear();
IBQuery1->SQL->Add(workstring);
IBTransaction1->Active = true;
IBQuery1->Open();
if (IBQuery1->FindFirst())
{
Memo1->Lines->Add("Got a result:");
Memo1->Lines->Add(IntToStr(IBQuery1->FieldByName("RECNO")->AsInteger));
}
else
{
Memo1->Lines->Add("IBQuery1 No result:");
Memo1->Lines->Add(workstring);
}
IBQuery1->Close();
IBTransaction1->Active = false;
IBDatabase1->Connected = false;
Query1->Close();
Query1->SQL->Clear();
Query1->SQL->Add(workstring);
Query1->Open();
if (Query1->FindFirst())
{
Memo1->Lines->Add("Got a result:");
Memo1->Lines->Add(IntToStr(Query1->FieldByName("RECNO")->AsInteger));
}
else
{
Memo1->Lines->Add("No result:");
Memo1->Lines->Add(workstring);
}
return;
}
 

Why are you calling FindFirst to see if the result set is empty? Either call
IsEmpty or check for Eof being true after the open. Either is a valid check for
an empty result set. When you open a dataset the cursor is on the first
record. According to the FindFirst help FindFirst returns false if the cursor
is not repositioned which in this case it won't be.
RWatkins writes:
Jeff Overcash (TeamB)
(Please do not email me directly unless asked. Thank You)
If there is somebody up there could they throw me down a line. Just a
little helping hand just a little understanding. Just some answers to the
questions that surround me now. If there's somebody up there could
they throw me down a line. (Fish)