Re: Concurrencty violation with decimal type
From: hb (hbranyan.SPAMBLOCK_at_merc.mercer.edu)
Date: 03/18/04
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Date: Thu, 18 Mar 2004 09:27:42 -0500
I had problems posting this reply, so sorry if it shows up twice.
"William (Bill) Vaughn" <billvaRemoveThis@nwlink.com> wrote in message
news:uKEt8sJDEHA.576@TK2MSFTNGP11.phx.gbl...
> It would be useful to see the UPDATE statement you're executing. If it's
> generated by the CommandBuilder or one of the drag-and-drop or DataAdapter
> Configuration wizard it could be that one of the columns don't match. I
> think this approach is pretty (fill in your own adjective). I suggest
using
> a simpler approach--put a TimeStamp column in your table and use it to
> determine if there are collisions. It's faster and easier to debug.
Thank you for the reply, Bill. You are the first and only so far out of all
the ngs and forums I've asked.
The Update statement is generated by the CommandBuilder. Since the table
being updated contains almost 100 columns (designed by previous contractor
on project, ugh), we thought the CommandBuilder would be the way to go.
We do a bit of massaging before the update executes.
First, we call
protected void CleanTableForUpdating() {
ArrayList colStrings = new ArrayList();
foreach (DataColumn col in requestDataTable.Columns) {
String colName = col.ColumnName.ToLower();
if (colName != "control_yr" && colName != "control_nr"
&& requestDataTable.Rows[0][colName,
DataRowVersion.Original].Equals(requestDataTable.Rows[0][colName,
DataRowVersion.Current])) {
colStrings.Add( colName );
}
}
foreach ( string column in colStrings ) {
requestDataTable.Columns.Remove( column );
}
}
Note: Control_Yr and Control_Nr are the primary key of the table. We remove
any other columns that have not been changed from the table, so the update
only affects the changed columns. We did this to make, as you said,
debugging easier. After CleanTableForUpdating(), the Update() is called on
the data adapter.
Then we do a bit of tracing in the RowUpdating handler.
public void daUpdatingHandler( object sender, OracleRowUpdatingEventArgs e)
{
HttpContext.Current.Trace.Write( "Row_Updating", e.Command.CommandText );
foreach( OracleParameter oraParam in e.Command.Parameters ) {
HttpContext.Current.Trace.Write( oraParam.SourceColumn,
oraParam.Value.ToString() );
}
}
This outputs the statement and the columns/values.
Here is an example statement:
UPDATE "TECHNICAL_ASSISTANCE_REQUESTS" SET "CRRNT_ARFRM_HRS"=:1 WHERE
"CONTROL_NR"=:2 AND "CONTROL_YR"=:3 AND "CRRNT_ARFRM_HRS"=:4
The columns/values are:
CRRNT_ARFRM_HRS 3088.3
CONTROL_NR 329
CONTROL_YR 2004
CRRNT_ARFRM_HRS 3088.6
So, if I take this statement and merge in the values, I have:
UPDATE TECHNICAL_ASSISTANCE_REQUESTS SET CRRNT_ARFRM_HRS = 3088.3 WHERE
CONTROL_NR = 329 AND CONTROL_YR = 2004 AND CRRNT_ARFRM_HRS = 3088.6
I then login via TOAD and execute the statement. No problem. However, the
statement fails in code and gives the concurrency violation error.
I have changed the variables I store CRRNT_ARFRM_HRS from decimal to double,
and I still get the same error. I think today I will try to just store it
as a string, since I don't think the values will be used for any
calculations.
If you have further suggestions, other than rewriting my entire class, I
look forward to them.
Hillarie
> "hb" <hbranyan.SPAMBLOCK@merc.mercer.edu> wrote in message
> news:c3ach3$25i546$1@ID-92475.news.uni-berlin.de...
> > Situation:
> >
> > Using a dataset's UpdateCommand, when a decimal type field changes from
> > integer to decimal, the update goes through. When the field changes from
> > decimal to integer or another decimal, I get a Concurrency violation:
the
> > UpdateCommand affected 0 records error.
> >
> > I have used trace to view the CommandText and all the source columns and
> > parameters. When I try to execute the update statement directly in the
> > database, the record updates. Just a code issue, apparently. I noticed
in
> a
> > search of these forums someone else had a similar problem, and they
solved
> > it, but never posted their fix.
> >
> > Any suggestions? using .NET 1.0 framework w/ ODP.NET data provider.
- Next message: Marina: "Same column names being renamed"
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- In reply to: William \(Bill\) Vaughn: "Re: Concurrencty violation with decimal type"
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