NET SQL Server数据访问抽象基础类

DbHelperSQL.CS

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;

/// <summary>
    /// 数据访问抽象基础类
    /// 2008-9-30
    /// </summary>
    public abstract class DbHelperSQL
    {
        //数据库连接字符串(web.config来配置)
        public static string connectionString = ConfigurationManager.AppSettings["ConnectionString"];

        public DbHelperSQL()
        {
        }

        #region 公用方法

        /// <summary>
        /// 获取表中字段中最大数
        /// </summary>
        /// <param name="FieldName">字段名</param>
        /// <param name="TableName">表名</param>
        /// <returns></returns>

        public static int GetMaxID(string FieldName, string TableName)
        {
            string strsql = "select max(" + FieldName + ")+1 from " + TableName;
            object obj = DbHelperSQL.GetSingle(strsql);
            if (obj == null)
            {
                return 1;
            }
            else
            {
                return int.Parse(obj.ToString());
            }
        }

        public static bool Exists(string strSql)
        {
            object obj = DbHelperSQL.GetSingle(strSql);
            int cmdresult;
            if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
            {
                cmdresult = 0;
            }
            else
            {
                cmdresult = int.Parse(obj.ToString());
            }
            if (cmdresult == 0)
            {
                return false;
            }