ADO.NET操作Access的问题

C# code:

public override int Update(Table model, DbTransaction dbtran)
{
StringBuilder strSql = new StringBuilder();
strSql.Append("update Table set ");
strSql.Append("Pid=@Pid,");
strSql.Append("Start=@Start,");
strSql.Append("CEnd=@CEnd");
strSql.Append(" where id=@id ");
OleDbParameter[] parameters = {
new OleDbParameter("@id", OleDbType.Integer,4),
new OleDbParameter("@Pid", OleDbType.Integer,4),
new OleDbParameter("@Start", OleDbType.Date),
new OleDbParameter("@CEnd", OleDbType.Date)};
parameters[0].Value = model.id;
parameters[1].Value = model.Pid;
parameters[2].Value = model.Start;
parameters[3].Value = model.CEnd;

return OleDbHelper.ExecuteSql(strSql.ToString(),dbtran, parameters);
}
/// <summary>
/// 执行SQL语句，返回影响的记录数,加事务参数
/// </summary>
/// <param name="SQLString">SQL语句</param>
/// <returns>新ID</returns>
public static int ExecuteSql(strin