Doug Hurst

[Doug Hurst]

"You can retrieve values of LOB fields using TOraQuery component the same way as you do for LONG or LONG RAW fields." is from the ODAC help in Borland C++ 5.0 (plus updates).

In C++ code, are there any examples of retrieving a BLOB to a file using the standard TOraQuery? Say I had a table with two columns, SSN Varchar and RECORD BLOB. In C++, how could I select (*) from this table and write each RECORD BLOB out to a file?

[Alex]

Please see our BlobPics and Long demo projects.

[Doug Hurst]

I'm trying. Can you tell me why this is not working? It compiles ok, but I get a access violation at runtime.

"Project OracleTest.exe raised exception class EAccessViolation with message 'Access violation at address..... Read address.....: Process stopped. Use..."

AnsiString asReceiptNumber;

try
{
OraQuery1->Close();
OraQuery1->SQL->Clear();
OraQuery1->SQL->Add(" select receipt_number, blob_field");
OraQuery1->SQL->Add(" from tmp_receipt_blob");
OraQuery1->SQL->Add(" where receipt_number = 'LIN9901050011'");
OraQuery1->Prepare();
if (OraQuery1->Prepared == true)
{
OraQuery1->Open();
if (OraQuery1->FindFirst() == true)
{
Memo->Lines->Add(OraQuery1->Fields->Fields[0]->AsString);
new TBlobField(OraQuery1->FieldByName("BLOB_FIELD"))->SaveToFile("junk.jpg");
}
}
}
catch(...)
{
Memo->Lines->Add("SQL failed.");
}

[Doug Hurst]

Never mind. This did the trick

void __fastcall TForm1::GetBLOBBtnClick(TObject *Sender)
{
AnsiString asReceiptNumber;

try
{
OraQuery1->Close();
OraQuery1->SQL->Clear();
OraQuery1->SQL->Add(" select receipt_number, blob_field");
OraQuery1->SQL->Add(" from tmp_receipt_blob");
OraQuery1->SQL->Add(" where receipt_number = 'LIN9901050011'");
OraQuery1->Prepare();
if (OraQuery1->Prepared == true)
{
OraQuery1->Open();
if (OraQuery1->FindFirst() == true)
{
Memo->Lines->Add(OraQuery1->Fields->Fields[0]->AsString);
OraQuery1->GetLob("BLOB_FIELD")->SaveToFile("junk.jpg");
}
}
}
catch(...)
{
Memo->Lines->Add("SQL failed.");
}
}
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