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From: "CJM" <cjmnews04@REMOVEMEyahoo.co.uk>
Newsgroups: comp.databases.oracle.server,microsoft.public.inetserver.asp.general
Subject: Problem repeating a query within an ADO Transaction
Date: Tue, 3 Apr 2007 17:48:29 +0100
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I have a fairly simple ASP application talking to an Oracle 10g DB using a 
mixture of ADO (OraOLEDB) and OO4O - the query here concerns some ADO code.

One part of the application records PartNo/SerialNo combinations; the user 
specifies a PartNo, a SerialNo and the parent PartNo - the parent takes the 
SerialNo from the child object - and the application INSERTs these as 
records into the DB.

Amongst the validation, is a check to confirm that each PartNo/SerialNo 
combination has not be used before. This code seems to work fine.
Clearly, if the user enters the same PartNo for both the child and parent 
items, the DB would ordinarily complain:

"ORA-00001: unique constraint (IFSAPP.PART_SERIAL_CATALOG_PK) violated 
ORA-06512"

However, I'm expecting the validation routines to handle this clash before 
the INSERT statement is attempted. Unfortunately, in this type of scenario 
this is not the case - the validation routine responds that the parent 
PartNo/SerialNo has not been used before, and thus the INSERT is attempted 
and the unique constraint error occurs.

I assume that this is because previous INSERTs were not committed since the 
whole operation is wrapped up within an ADO transaction. However, I would 
have expected that the validation code would have taken an changes made 
within the transaction into account, but it doesn't appear to be the case.

Is my logic wrong, or should I be expecting the validation to consider 
previous statements within the same transaction?  If my expectations are 
correct, where might I be going wrong?

Thanks in advance

Chris


Selected code snippets:
- ASP:

Function SerialExists (sSerialNo, sPartNo)
 Dim iResult, bResult

 With oDB
  .Parameters.Add "sPartNo", sPartNo, ORAPARM_INPUT, 1
  .Parameters.Add "sSerialNo", sSerialNo, ORAPARM_INPUT, 1
  .Parameters.Add "iResult", 0, ORAPARM_OUTPUT
  .Parameters("iResult").serverType = 1

  .ExecuteSQL ("declare iResult VARCHAR2(100); Begin :iResult := 
IFSAPP.PART_SERIAL_CATALOG_API.CHECK_EXIST(:sPartNo, :sSerialNo); end;")

  SerialExists = .Parameters("iResult").Value

  .Parameters.Remove "sPartNo"
  .Parameters.Remove "sSerialNo"
  .Parameters.Remove "iResult"

 End With
End Function


- Oracle:

FUNCTION Check_Exist___ (
   part_no_ IN VARCHAR2,
   serial_no_ IN VARCHAR2 ) RETURN BOOLEAN
IS
   dummy_ NUMBER;
   CURSOR exist_control IS
      SELECT 1
      FROM   PART_SERIAL_CATALOG_TAB
      WHERE part_no = part_no_
      AND   serial_no = serial_no_;
BEGIN
   OPEN exist_control;
   FETCH exist_control INTO dummy_;
   IF (exist_control%FOUND) THEN
      CLOSE exist_control;
      RETURN(TRUE);
   END IF;
   CLOSE exist_control;
   RETURN(FALSE);
END Check_Exist___;