我试图把日期作为字符串存储在一个表中,但是这个日期一直转换成一个负的4位数,这个数与日期有关,但是我无法找出我到底哪里出错了。请注意,我正在使用C#和SQL Server的组合。
foreach(DataRow dr in dt.Rows)
{
int qty = 0;
string pname = "";
SqlCommand cmd3 = con.CreateCommand();
cmd3.CommandType = CommandType.Text;
cmd3.CommandText = "insert into order_item values('" + orderid.ToString() + "','" + dr["product"].ToString() + "'," +
"'" + dr["price"].ToString() + "','" + dr["qty"].ToString() + "','"+ dr["total"].ToString() + "')";
cmd3.ExecuteNonQuery();
qty = Convert.ToInt32(dr["qty"].ToString());
pname = dr["product"].ToString();
SqlCommand cmd6 = con.CreateCommand();
cmd6.CommandType = CommandType.Text;
cmd6.CommandText = "update stock set product_qty = product_qty - " + qty + " where product_name = '"+pname.ToString()+"'";
cmd6.ExecuteNonQuery();
// date keeps getting updated to negative 4 digit number which coordinates with the date. ex: 14-01-2020 is converting to -2007.
SqlCommand cmd7 = con.CreateCommand();
cmd7.CommandType = CommandType.Text;
**cmd7.CommandText = "update stock_over_time set product_qty = product_qty - " + qty + ", date_changed = " + date.ToString("dd-MM-yyyy") + "" +
" where product_name = '" + pname.ToString() + "'";**
cmd7.ExecuteNonQuery();
}