C# 增删改查应用（四）

      //读取配置文件，连接数据库语句
        public static string strCon = System.Configuration.ConfigurationManager.ConnectionStrings["Family"].ConnectionString;

        private static OleDbConnection oleConn = new OleDbConnection(strCon);//access database

        /// <summary>
        /// 根据命令增加
        /// </summary>
        /// <param name="sql"></param>
        /// <returns></returns>
        public static int Insert(string sql)
        {
            int result = 0;
            try
            {
                oleConn.Open();
                OleDbCommand oleCommand = new OleDbCommand(sql, oleConn);
                result = oleCommand.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally { oleConn.Close(); }
            return result;
        }

        /// <summary>
        /// 根据命令查询表
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <returns></returns>
        public static DataTable Select(string sql)
        {
            DataTable tb = new DataTable();
            try
            {
                oleConn.Open();
                OleDbDataAdapter adapter = new OleDbDataAdapter(sql, oleConn);
                adapter.Fill(tb);
            }
            catch (Exception exception)
            {
                string message = exception.Message;
            }
            finally { oleConn.Close(); }
            return tb;
        }

        /// <summary>
        /// 根据命令删除
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <returns></returns>
        public static int Delete(string sql)
        {
            int ifExecute = 0;
            try
            {
                oleConn.Open();
                OleDbCommand comm = new OleDbCommand(sql);
                ifExecute = comm.ExecuteNonQuery();
            }
            finally
            {
                oleConn.Close();
            }
            return ifExecute;
        }
        /// <summary>
        /// 更新数据
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <returns></returns>
        public static int Update(string sql)
        {
            int ifExecute = 0;
            try
            {
                oleConn.Open();
                OleDbCommand comm = new OleDbCommand(sql, oleConn);
                ifExecute = comm.ExecuteNonQuery();
            }
            finally
            {
                oleConn.Close();
            }
            return ifExecute;
        }

        /// <summary>
        /// 执行sql返回对象
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <returns></returns>
        public static object ExecuteSingle(string sql)
        {
            object obj = null;
            try
            {
                oleConn.Open();
                OleDbCommand comm = new OleDbCommand(sql, oleConn);
                obj = comm.ExecuteScalar();
            }
            finally
            {
                oleConn.Close();
            }
            return obj;
        }