The following query in C# doesn't work, but I can't see the problem:
string Getquery = "select * from user_tbl where emp_id=@emp_id and birthdate=@birthdate";
cmdR.Parameters.AddWithValue("@emp_id", userValidate.emp_id);
cmdR.Parameters.AddWithValue("@birthdate", userValidate.birthdate);
OdbcCommand cmdR = new OdbcCommand(Getquery, conn);
OdbcDataReader Reader = cmdR.ExecuteReader();
Reader.HasRows returns no result but when I query it to my database I got data.
I'll assume your code is actually not quite as presented, given that it wouldn't currently compile - you're using cmdR before you declare it.
First, you're trying to use named parameters, and according to the documentation of OdbcCommand.Parameters, that isn't supported:
When
CommandTypeis set toText, the .NET Framework Data Provider for ODBC does not support passing named parameters to an SQL statement or to a stored procedure called by anOdbcCommand. In either of these cases, use the question mark (?) placeholder.
Additionally, I would personally avoid using AddWithValue anyway - I would use something like:
string sql = "select * from user_tbl where emp_id = ? and birthdate = ?";
using (var connection = new OdbcConnection(...))
{
connection.Open();
using (var command = new OdbcCommand(sql, connection))
{
command.Parameters.Add("@emp_id", OdbcType.Int).Value = userValidate.EmployeeId;
command.Parameters.Add("@birthdate", OdbcType.Date).Value = userValidate.BirthDate;
using (var reader = command.ExecuteReader())
{
// Use the reader here
}
}
}
This example uses names following .NET naming conventions, and demonstrates properly disposing of resources... as well as fixing the parameter issue.
I do think it's slightly unfortunate that you have to provide a name for the parameter when adding it to the command even though you can't use it in the query, but such is life.
Use like this:
string Getquery = "select * from user_tbl where emp_id=? and birthdate=?";
cmdR.Parameters.AddWithValue("@emp_id", userValidate.emp_id);
cmdR.Parameters.AddWithValue("@birthdate", userValidate.birthdate);
OdbcCommand cmdR = new OdbcCommand(Getquery, conn);
OdbcDataReader Reader = cmdR.ExecuteReader();
while(Reader.Read())
{
//Do something;
}
I know this thread is old, but I wanted to share my solution for anyone else coming up on this.
I was having issues with the typical method that Jon posted. I have used it before, but for some reason with this new string I had it was not wanting to actually place the parameter correctly and was causing the reader to not work.
I ended up doing something like this instead, since in the end we are just replacing parts of a string.
string sql = "select * from user_tbl where emp_id = "+ var1 +" and birthdate = "+
var2""
OdbcCommand command = new OdbcCommand(sql);
This was easier for me to get to work. Be warned though, I am not sure if it has any specific drawbacks when compare to using the command parameter method.
