Question

I have created the EF model and then in a Class I have written the following Code to retrieve the value form the DataBase. And store the value in another Table. But it gives me the Error “DATAREADER IS INCompatable” as explained Below..

      EmpRole empr = new EmpRole();
        empr.EmpId = strEmpId;
      string str="select RoleId from RoleName where roleName like '"+strDesignation+"'";
      var context= DbAccess.Data.ExecuteStoreQuery<RoleName>(str, null);  //Here Showing Error

        empr.RoleId = Convert.ToInt16(context);
        DbAccess.Data.EmpRoles.AddObject(empr);
        DbAccess.Commit();

It’s showing the error like:

DataTables were:

CREATE TABLE [dbo].[RoleName](
    [SNo] [int] IDENTITY(1,1) NOT NULL,
    [RoleId] [smallint] NOT NULL,
    [RoleName] [varchar](50) NULL,
 CONSTRAINT [PK_RoleName] PRIMARY KEY CLUSTERED 
(
    [RoleId] ASC
)

CREATE TABLE [dbo].[EmpRoles](
    [Sno] [int] IDENTITY(1,1) NOT NULL,
    [EmpId] [varchar](8) NOT NULL,
    [RoleId] [smallint] NOT NULL,
    [ReportingToId] [varchar](8) NULL,
 CONSTRAINT [PK_EmpRoles] PRIMARY KEY CLUSTERED 
(
    [Sno] ASC
)

The data reader is incompatible with the specified ‘MyOrgDBModel.RoleName’. A member of the type, ‘SNo’, does not have a corresponding column in the data reader with the same name.

Please tell me the reasons what to do to execute the sqlQuery.

Answer 1

This is because you are not selecting the SNo column in your select query. As you are populating in RoleName and it has property SNo column should be present in data reader. If you just want the RoleId to be in query then create new type with one property RoleId and use this. Create new type like below

public class CustomRoleName
{
    int RoleId { get; set; }
}

Now change your code as follow

EmpRole empr = new EmpRole();
empr.EmpId = strEmpId;
string str="select RoleId from RoleName where roleName like '"+strDesignation+"'";
foreach(CustomRoleName rn in  DbAccess.Data.ExecuteStoreQuery<CustomRoleName>(str))
{
     empr.RoleId = rn.RoleId ;
     DbAccess.Data.EmpRoles.AddObject(empr);
     DbAccess.Commit();
     break;
}