Inserting DateTime into Sql Server 2005

Question

I have a problem inserting a datetime format variable to Sql Server 2005 database. DateTime Format is dd.MM.yyyy

conn.Open();

                string conString = "SET DATEFORMAT DMY INSERT INTO AmortPlanT (InvestmentID,StartDate,Maturity,IRate,CoupPerYear,parValue) Values (@IIndex,'@StartDate','@Maturity',@IRate,@CouponPerYear,@parValue)";

                using (SqlCommand myCommand = new SqlCommand(conString, conn))
                {
                    myCommand.CommandType = CommandType.Text;
                    myCommand.Parameters.Add("@IIndex", SqlDbType.Int).Value = investmentIndex;
                    myCommand.Parameters.Add("@StartDate", SqlDbType.DateTime).Value = startDate;
                    myCommand.Parameters.Add("@Maturity", SqlDbType.DateTime).Value = maturity;
                    myCommand.Parameters.Add("@IRate", SqlDbType.Float).Value = iRate;
                    myCommand.Parameters.Add("@CouponPerYear", SqlDbType.Int).Value = coupPerYear;
                    myCommand.Parameters.Add("@parValue", SqlDbType.Float).Value = parValue;

                    myCommand.ExecuteNonQuery();

                }

StartDate and Maturity are DateTime variables i get from dateTimePicker.Value .

And i'm always getting the error:

Conversion failed when converting datetime from character string.

Thank you for your help.

Answer 1

You are not supposed to put your parameters in quotes.. here is the correct query..

'@StartDate' in values clause is wrong, it should be just @StartDate... as explained below...

    conn.Open();
    string conString = "SET DATEFORMAT DMY INSERT INTO AmortPlanT 
(InvestmentID,StartDate,Maturity,IRate,CoupPerYear,parValue) Values 
(@IIndex,@StartDate,@Maturity,@IRate,@CouponPerYear,@parValue)";                
using (SqlCommand myCommand = new SqlCommand(conString, conn))
   {                    
    myCommand.CommandType = CommandType.Text;                    
    myCommand.Parameters.Add("@IIndex", SqlDbType.Int).Value = investmentIndex;                    
    myCommand.Parameters.Add("@StartDate", SqlDbType.DateTime).Value = startDate;                    
    myCommand.Parameters.Add("@Maturity", SqlDbType.DateTime).Value = maturity;                    
    myCommand.Parameters.Add("@IRate", SqlDbType.Float).Value = iRate;                    myCommand.Parameters.Add("@CouponPerYear", SqlDbType.Int).Value = coupPerYear;                    
myCommand.Parameters.Add("@parValue", SqlDbType.Float).Value = parValue;                    myCommand.ExecuteNonQuery();                
}

Answer 2

The problem is that you are thinking in terms of strings...

DateTime Format is dd.MM.yyyy

No, it isn't; the format of a DateTime (when passed as a parameter) is really just a number as binary ;-p ( startDate should be a DateTime - not a string ).

When you are using parameters, you don't include the string tokens ( ' ) - otherwise you mean "the string '@name' ", rather than "the string held in parameter @name "; try removing them:

string conString = @"
SET DATEFORMAT DMY INSERT INTO AmortPlanT (InvestmentID,StartDate,Maturity,IRate,CoupPerYear,parValue)
VALUES (@IIndex,@StartDate,@Maturity,@IRate,@CouponPerYear,@parValue)";