下面是数据库操作集锦，使用前先添加命名空间using System.Data.SqlClient;

/// 
        /// 还回DataTable类型        /// 
        /// SQL语句        /// 
              public static DataTable ExcuteSQL(string sql)        {            DataTable dt = null;            string connstring="server=localhost;database=DataBase;Uid=username;pwd=userpass";            using (SqlConnection sqlconn = new SqlConnection(connstring))            {                sqlconn.Open();                SqlCommand slcom = sqlconn.CreateCommand();                slcom.CommandText = sql;                SqlDataAdapter adap = new SqlDataAdapter(slcom);                adap.Fill(dt);                sqlconn.Close();            }            return dt;        }        /// 
        /// 返回Object类型        /// 
        /// SQL语句        /// 
              public static Object ExcuteSQLScalar(string sql)        {            Object ob = null;            string connstring="server=localhost;database=DataBase;Uid=username;pwd=userpass";            using (SqlConnection sqlconn = new SqlConnection(connstring))            {                sqlconn.Open();                SqlCommand slcom = sqlconn.CreateCommand();                slcom.CommandText = sql;                ob = slcom.ExecuteScalar();                sqlconn.Close();            }            return ob;        }        /// 
        /// 不返回任何值        /// 
        /// SQL语句        public static void SQLExcuteNone(string sql)        {            string connstring="server=localhost;database=DataBase;Uid=username;pwd=userpass";            using (SqlConnection sqlconn = new SqlConnection(connstring))            {                sqlconn.Open();                SqlCommand slcom = sqlconn.CreateCommand();                slcom.CommandText = sql;                slcom.ExecuteNonQuery();                sqlconn.Close();            }        }