Sqlite无法更新

C# code:
public static bool UpdateFriendUrl(int id, string cnName, string jpName, string logoUrl, string site, int order)
{
string sql = "update FriendUrl set SiteNameCN=@SiteNameCN,SiteNameJP=@SiteNameJP,SiteLogo=@SiteLogo,SiteUrl=@SiteUrl,
SiteSort=@SiteSort where ID=@ID";

using (SQLiteConnection cn = new SQLiteConnection(ConnString))
{
using (SQLiteCommand cmd = new SQLiteCommand())
{
cn.Open();
cmd.Connection = cn;
cmd.CommandText = sql;
cmd.CommandType = CommandType.Text;
cmd.Parameters.Add("@ID", DbType.Int32).Value = id;
cmd.Parameters.Add("@SiteNameCN", DbType.String, 100).Value = cnName;
cmd.Parameters.Add("@SiteNameJP", DbType.String, 100).Value = jpName;
cmd.Parameters.Add("@SiteLogo", DbType.String, 100).Value = logoUrl;
cmd.Parameters.Add("@SiteUrl", DbType.String, 100).Value = site;
cmd.Parameters.Add("@SiteSort", DbType.Int32).Value = order;
try
{
cmd.ExecuteNonQuery();
return true;

}
catch
{
return false;