更新查询无济于事

Question

I am trying to call the following query (parameters are in alphabetical order):

public const string UpdateSample =
    @"UPDATE subReceivingQC
      SET Clerk=@Clerk, Comments=@Comments, CommentsProd=@CommentsProd, GRV=@GRV, 
          MassOff=@MassOff, PalletID=@PalletID, PalletSeq=@PalletSeq, PONo=@PONo, 
          QCDate=@QCDate, QtyInspected=@QtyInspected, SampleNo=@SampleNo, 
          StatusClerk=@StatusClerk, StatusSupervisor=@StatusSupervisor, Supervisor=@Supervisor
      WHERE GRV=@GRV AND PalletSeq=@PalletSeq AND SampleNo=@SampleNo;";

Using this method:

internal int UpdateSample(Sample sample)
{
    using (var db = new OleDbConnection(ConnectionString))
    {
        var query = Constants.UpdateSample;
        return db.Execute(query, sample);
    }
}

The Execute() command is successful (in that no exceptions appear), but UpdateSample keeps returning 0 , and the database entry remains unchanged.

I have used this exact patter for other db operations ( INSERT and SELECT ) without any issue.

The only related issues I can find were resolved by sorting the parameters in the query (mine already sorted).

Does anyone have any insight on what is going on here, or how I can go about debugging this?

Following on from Steve's comment, I have not included any code for adding parameters to the command, as I am under the impression that these are obtained automatically from the Model .

---

Properties available in the Sample model:

public class Sample : IGriddable
{
    public string[] ColumnHeaders { get; } = new string[] { "SampleNo", "QCDate", "StatusClerk", "StatusSupervisor" };
    public string RowLinkPrefix { get { return $"/receiving/{Pallet.Grv.GRVNo}/{Pallet.PalletSeq}/"; } }
    public bool Selectable { get; } = true;

    public Pallet Pallet { get; set; }

    public string Clerk { get; set; }
    public string MassOff { get; set; }
    public string CommentsProd { get; set; }
    public string QtyInspected { get; set; }
    public string Supervisor { get; set; }
    public string Comments { get; set; } 

    public string SampleNo { get; set; }
    public string StatusClerk { get; set; }
    public string StatusSupervisor { get; set; }
    public string ProductSpec { get; set; }

    // For required db params
    public string GRV { get; set; }
    public string PalletID { get; set; }
    public string PalletSeq { get; set; }
    public string PONo { get; set; }

    [DisplayFormat(DataFormatString = "{0:dd/MM/yyyy}", ApplyFormatInEditMode = true)]
    public DateTime QCDate { get; set; }

    // Each defect status needs to be saved as a (DB)subQCItems item
    public List<QCItem> Defects { get; set; } = new List<QCItem>();
    public List<string> ImagePaths { get; set; } = new List<string>();
}

Answer 1

OleDb requires that you pass the parameters in the same exact order in which you present them in the command text. If you don't do it, then wrong values could be used for the WHERE statement and, if you are unlucky you could end to change a wrong record, or simply you don't update anything.

Unfortunately Dapper doesn't take in consideration this in its algorithms used to prepare the command. Sql Server and other providers with named parameters and no constraints about order don't have this problem. Instead adding the code to create and order correctly the parameters based on your query text could be very costly for performances.
I believe they thought this didn't worth the effort and that you can simply resolve the problem defining yourself the parameters.

So you are on your own on this point and you should use the version of Execute that takes a DynamicParameters parameter

using (var db = new OleDbConnection(ConnectionString))
{
    var query = Constants.UpdateSample;

    DynamicParameters pars = new DynamicParameters();
    pars.Add("@Clerk", sample.Clerk, DbType.String);
    // ... and so on for all parameters following the order of the placeholders

    // but end with ....
    pars.Add("@GRV", sample.GRV, DbType.String);
    pars.Add("@PalletSeq", sample.PalletSeq, DbType.String);
    pars.Add("@SampleNo", sample.SampleNo, DbType.String);

    return db.Execute(query, pars);
}

Answer 2

which database are you using ? if SQL Server, use SQL Profiler to find out the exact query being executed.

if you are not using SQL server, try to execute the query yourself in the database without oledb. It probably is a parameter issue in which the where-clause does not lead to any results. Which value do @GRV , @PalletSeq and @SampleNo have ? if no records match that combination, obviously nothing happens