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asp.net 数据访问层基类

来源:中国IT实验室 作者:佚名 发表于:2013-04-27 13:13  点击:
部分代码: 复制代码 代码如下: using System; using System.Collections; using System.Collections.Specialized; using System.Data; using System.Data.SqlClient; using System.Configuration; using System.Data.Common; using System.Collections.Gener
部分代码:  复制代码 代码如下:
  using System;
  using System.Collections;
  using System.Collections.Specialized;
  using System.Data;
  using System.Data.SqlClient;
  using System.Configuration;
  using System.Data.Common;
  using System.Collections.Generic;
  namespace sosuo8.DBUtility
  {
  public abstract class DbHelperSQL
  {
  //数据库连接字符串
  public static string connectionString = ConfigurationManager.ConnectionStrings["Conn"].ToString();
  public static SqlConnection conn = new SqlConnection(connectionString);
  public DbHelperSQL()
  {
  }
  #region 公用方法
  /// <summary>
  /// 判断是否存在某表的某个字段
  /// </summary>
  /// <param name="tableName">表名称</param>
  /// <param name="columnName">列名称</param>
  /// <returns>是否存在</returns>
  public static bool ColumnExists(string tableName, string columnName)
  {
  string sql = "select count(1) from syscolumns where [id]=object_id('" + tableName + "') and [name]='" + columnName + "'";
  object res = GetSingle(sql);
  if (res == null)
  {
  return false;
  }
  return Convert.ToInt32(res) > 0;
  }
  public static int GetMaxID(string FieldName, string TableName,string wherestr)
  {
  string strsql = "select max(" + FieldName + ")+1 from " + TableName;
  if (wherestr != string.Empty)
  {
  strsql += " where " + wherestr;
  }
  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;
  }
  else
  {
  return true;
  }
  }
  /// <summary>
  /// 表是否存在
  /// </summary>
  /// <param name="TableName"></param>
  /// <returns></returns>
  public static bool TabExists(string TableName)
  {
  string strsql = "select count(*) from sysobjects where id = object_id(N'[" + TableName + "]') and OBJECTPROPERTY(id, N'IsUserTable') = 1";
  //string strsql = "SELECT count(*) FROM sys.objects WHERE object_id = OBJECT_ID(N'[dbo].[" + TableName + "]') AND type in (N'U')";
  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;
  }
  else
  {
  return true;
  }
  }
  }

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