SQL查询“条件表达式中的数据类型不匹配。”

Question

I'm working on Form that sends about 9 fields to my SQL ACCESS database and i got this error. "Data type mismatch in criteria expression." i'm sure it's something with the ' x ' i put in my query but still can't figure out what is THE problem.

it's (int,int,string,string,string,int,int,string,int,int) format

string SqlStr = string.Format("insert into Orders(client_id,order_id,date_,card_typ,pay_mthd,ex_y,ex_m,cc_comp,cc_num,t_sale)values({0},{1},'{2}','{3}','{4}',{5},{6},'{7}',{8},{9})", s.ClientId,s.OrderId,s.Date,s.CardTyp,s.PayMethod,s.Ex_Y,s.Ex_M,s.CcComp,s.CcNum,s.TotalSale);

Thanks for your help.

Answer 1

String.Format will not be a good approach for building queries. I suggest you to use, Parameterised queries that helps you to specify the type too and also its more helpful to prevent injection: Here is an example for you:

string query = "insert into Orders" +
               "(client_id,order_id,date_,card_typ,...)" +
               " values(@client_id,@order_id,@date_,@card_typ...)";
using (SqlCommand sqCmd = new SqlCommand(query, con))
{
    con.Open();
    sqCmd.Parameters.Add("@client_id", SqlDbType.Int).Value = s.ClientId;
    sqCmd.Parameters.Add("@order_id", SqlDbType.VarChar).Value = s.OrderId;
    sqCmd.Parameters.Add("@date_", SqlDbType.DateTime).Value = s.Date;
    sqCmd.Parameters.Add("@card_typ", SqlDbType.Bit).Value = s.CardTyp;
    // add rest of parameters
   //Execute the commands here
}

Note: I have included only few columns in the example, you can replace ... with rest of columns.

Answer 2

Please dont use a concatenation string ...

Here is an example :

        using (SqlConnection connection = new SqlConnection("...connection string ..."))
        {
            SqlCommand command = new SqlCommand("insert into Orders(client_id,order_id,date_,card_typ,pay_mthd,ex_y,ex_m,cc_comp,cc_num,t_sale)values(@client_id,@order_id,@date_,@card_typ,@pay_mthd,@ex_y,@ex_m,@cc_comp,@cc_num,@t_sale)", connection);
            SqlParameter pclient_id = new SqlParameter("@client_id", System.Data.SqlDbType.Int);
            pclient_id.Value = 12;
            command.Parameters.Add(pclient_id);
            SqlParameter pcard_typ = new SqlParameter("@card_typ", System.Data.SqlDbType.VarChar);
            pcard_typ.Value = "some value";
            command.Parameters.Add(pcard_typ);

            try
            {
                connection.Open();
                command.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                Debug.WriteLine(ex.Message);
            }
            finally
            {
                connection.Close();
            }

        }