数据库插入错误:"字符串或二进制数据将被截断"

Question

当我登录时,我将我的用户名存储在会话中.我的要求是我想将我的用户名存储在我的数据库中.我在这里存储它username1.输入用户名后,我可以使用response.write()它打印并完美打印.但是,当我将它存储在数据库中时,它会产生以下错误:

**sqlException was unhandled by user code
and exception at       cmd.ExecuteScalar();
String or binary data would be truncated.
The statement has been terminated.**

以下是我的ado.net代码:

using (SqlConnection con = 
    new SqlConnection("Data Source=.;database=testdb1;Integrated Security=SSPI")) {

    con.Open();
    //  SqlCommand cmd = new SqlCommand("delete from fileinfo where ID=" + Convert.ToInt32(Request.Params["one"]), con);                            

    string uname = (string) Session["fname"].ToString() + " " + Session["lname"].ToString(); //Session["fname"].ToString()+" "+Session["lname"].ToString();

    // Response.Write(uname);
    // uname = "sri hari";
    uname = uname + " ";
    string uname1 = uname;
    uname = uname.Trim();
    SqlCommand cmd = new SqlCommand("insert into qry_details values('" + txt_query_name.Text + "','pending for approval','" + txt_query_description.Text + "','" + DateTime.Now.ToString("yyyy-MM-dd") + "','" + qry + "','" + uname1 + "')", con);
    cmd.ExecuteScalar();
}

Answer 1

检查qry_details表的长度,看它是否小于你发送给db的字符串？

基本上例外,你说你正在尝试比列长更大的东西.

Answer 2

我建议你使用参数化查询.您的代码现在容易受到SQL注入攻击.您还应该ExecuteNonQuery在SQL命令上使用该方法,而不是ExecuteScalar在将值插入数据库时​​:

var connectionString = "Data Source=.;database=testdb1;Integrated Security=SSPI";
using (SqlConnection con = new SqlConnection(connectionString))
using (SqlCommand cmd = con.CreateCommand())
{
    con.Open();
    cmd.CommandText = "INSERT INTO qry_details VALUES (@query_name, 'pending for approval', @query_description, @date, @qry, @username)";
    cmd.Parameters.AddWithValue("@query_name", txt_query_name.Text);
    cmd.Parameters.AddWithValue("@query_description", txt_query_description.Text);
    cmd.Parameters.AddWithValue("@date", DateTime.Now);
    cmd.Parameters.AddWithValue("@qry", qry);
    cmd.Parameters.AddWithValue("@username", uname1);
    cmd.ExecuteNonQuery();
}