DataAdapter call ExecuteReader instead of ExecuteNonQuery

  • Thread starter Thread starter Lionel LASKE
  • Start date Start date
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Lionel LASKE

I'm working on my own implementation of an ADO.NET Data Provider
derived from IDbXXXX classes and MSDN sample
(http://msdn.microsoft.com/library/d...ide/html/cpconImplementingNETDataProvider.asp).
All is fine when I execute simple Command and DataReader but I got an
error with DataAdapter.
Running of SelectCmd and InsertCmd work fine but each UpdateCmd or
DeleteCmd thrown a DBConcurrencyException.
It seems that problem is that DataAdapter call ExecuteReader instead
of ExecuteNonQuery on InsertCmd, UpdateCmd and DeleteCmd. So, number
of row affected is probably incorrect.
Do I miss something or is it an usual way of working for a DataAdapter
?
Why ExecuteReader is called for an Update and a Delete without any
result expected ?
Thanks in advance for your help or advices.

Lionel.
 
Hi Lionel,

I guess the reader part is because of concurrency issues (to load timestamp
or autoinc key).
See help on
IDbCommand.UpdatedRowSource Property
 
Thanks for your answer but my DataSet don't have any autoinc or timestamp
key and I have just one access on my table (local database).
I tried all enum value in System.Data.UpdateRowSource and I have the same
exception thrown: DBConcurrencyException.
I'm really wonder why for an UPDATE command DbDataAdapter.Update calls my
command with ExecuteReader instead of ExecuteNonQuery. Here is my source
code:


// ... On init

dataAdapter = new MyADOProvider.MyDataAdapter(selectCmd);
dataAdapter.UpdateCommand = new MyADOProvider.MyCommand("MyProc
@action='UPDATE',", cnx);
dataAdapter.UpdateCommand.CommandType = CommandType.StoredProcedure;
param = dataAdapter.UpdateCommand.CreateParameter();
param.DbType = DbType.Int32;
param.ParameterName = "@code";
dataAdapter.UpdateCommand.Parameters.Add(param);
param = dataAdapter.UpdateCommand.CreateParameter();
param.DbType = DbType.String;
param.ParameterName = "@name";
dataAdapter.UpdateCommand.Parameters.Add(param);

dataSet = new DataSet();
dataAdapter.Fill(dataSet, "results");


//... On Update button

dataAdapter.Update(dataSet, "results");

My guess is that with a ExecuteNonQuery, you can have a "Number of rows
affected" but you can't have this number with a ExecuteReader.
Is someone know the source code of DbDataAdapter.Update ?

Lionel.


Miha Markic said:
Hi Lionel,

I guess the reader part is because of concurrency issues (to load
timestamp or autoinc key).
See help on
IDbCommand.UpdatedRowSource Property

--
Miha Markic [MVP C#] - RightHand .NET consulting & development
SLODUG - Slovene Developer Users Group
www.rthand.com

Lionel LASKE said:
I'm working on my own implementation of an ADO.NET Data Provider
derived from IDbXXXX classes and MSDN sample
(http://msdn.microsoft.com/library/d...ide/html/cpconImplementingNETDataProvider.asp).
All is fine when I execute simple Command and DataReader but I got an
error with DataAdapter.
Running of SelectCmd and InsertCmd work fine but each UpdateCmd or
DeleteCmd thrown a DBConcurrencyException.
It seems that problem is that DataAdapter call ExecuteReader instead
of ExecuteNonQuery on InsertCmd, UpdateCmd and DeleteCmd. So, number
of row affected is probably incorrect.
Do I miss something or is it an usual way of working for a DataAdapter
?
Why ExecuteReader is called for an Update and a Delete without any
result expected ?
Thanks in advance for your help or advices.

Lionel.
Click to expand...
Click to expand...
 
Lionel LASKE said:
Thanks for your answer but my DataSet don't have any autoinc or timestamp
key and I have just one access on my table (local database).
I tried all enum value in System.Data.UpdateRowSource and I have the same
exception thrown: DBConcurrencyException.
I'm really wonder why for an UPDATE command DbDataAdapter.Update calls my
command with ExecuteReader instead of ExecuteNonQuery. Here is my source
code:
Click to expand...

Hmm, I don't see any UpdateRowSource setting in your code.
// ... On init

dataAdapter = new MyADOProvider.MyDataAdapter(selectCmd);
dataAdapter.UpdateCommand = new MyADOProvider.MyCommand("MyProc
@action='UPDATE',", cnx);
dataAdapter.UpdateCommand.CommandType = CommandType.StoredProcedure;
param = dataAdapter.UpdateCommand.CreateParameter();
param.DbType = DbType.Int32;
param.ParameterName = "@code";
dataAdapter.UpdateCommand.Parameters.Add(param);
param = dataAdapter.UpdateCommand.CreateParameter();
param.DbType = DbType.String;
param.ParameterName = "@name";
dataAdapter.UpdateCommand.Parameters.Add(param);

dataSet = new DataSet();
dataAdapter.Fill(dataSet, "results");


//... On Update button

dataAdapter.Update(dataSet, "results");

My guess is that with a ExecuteNonQuery, you can have a "Number of rows
affected" but you can't have this number with a ExecuteReader.
Is someone know the source code of DbDataAdapter.Update ?
Click to expand...

Sure, try with Reflector.
http://www.aisto.com/roeder/dotnet/
 
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