DbHelper-SQL数据库访问助手代码,CSharp代码库,德仔网

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【CSharp】 DbHelper-SQL数据库访问助手
作者:Egbert / 发布于2016/1/4/ 1107

	using System;
	using System.Data;
	using System.Data.SqlClient;

	namespace Whir.Software.Framework.Ultimate
	{
	 /// <summary>
	 /// 数据库访问助手
	 /// </summary>
	 public class DbHelper
	 {
	 #region 判断连接是否成功
	 /// <summary>
	 /// 判断连接是否成功！
	 /// </summary>
	 /// <param name="con"> 链接字符串</param>
	 /// <returns>true 表示链接成功，false表示连接失败</returns>
	 public static bool IsConnected(string con)
	 {
	 bool flag;
	 var conn = new SqlConnection(con);
	 try
	 {
	 conn.Open();
	 flag = true;
	 }
	 catch (Exception)
	 {
	 flag = false;
	 }
	 finally
	 {
	 conn.Close();
	 }
	 return flag;
	 }
	 #endregion
	 #region 执行不带参数sql语句
	 /// <summary>
	 /// 执行不带参数sql语句
	 /// </summary>
	 /// <param name="sql">增，删，改sql语句</param>
	 /// <param name="con"></param>
	 /// <returns>返回所影响的行数</returns>
	 public static bool Execute(string sql, string con)
	 {
	 var cmd = new SqlCommand();
	 var connection = new SqlConnection(con);
	 try
	 {
	 using (connection)
	 {
	 cmd.Connection = connection;
	 cmd.CommandText = sql;
	 connection.Open();
	 cmd.ExecuteNonQuery();
	 return true;
	 }
	 }
	 catch (Exception)
	 {
	 return false;
	 }
	 }
	 #endregion
	 #region 执行SQL语句返回DataTable
	 /// <summary>
	 /// 执行SQL语句返回DataTable
	 /// </summary>
	 /// <param name="sql"></param>
	 /// <param name="con"></param>
	 /// <returns></returns>
	 public static DataTable ExcuteDataTable(string sql, string con)
	 {
	 var cmd = new SqlCommand();
	 var connection = new SqlConnection(con);
	 try
	 {
	 using (connection)
	 {
	 cmd.Connection = connection;
	 cmd.CommandText = sql;
	 connection.Open();
	 var da = new SqlDataAdapter(cmd);
	 var ds = new DataSet();
	 da.Fill(ds);
	 return ds.Tables[0];
	 }
	 }
	 catch (Exception ex)
	 {
	 var dt = new DataTable();
	 dt.Columns.Add("异常信息");
	 DataRow row = dt.NewRow();
	 row["异常信息"] = ex.Message;
	 dt.Rows.Add(row);
	 return dt;
	 }
	 }
	 #endregion
	 #region 执行SQL语句查询单条记录
	 /// <summary>
	 /// 执行SQL语句查询单条记录
	 /// </summary>
	 /// <param name="sql"></param>
	 /// <param name="con"></param>
	 /// <returns></returns>
	 public static object ExecuteScalar(string sql, string con)
	 {
	 var cmd = new SqlCommand();
	 var connection = new SqlConnection(con);
	 try
	 {
	 using (connection)
	 {
	 cmd.Connection = connection;
	 cmd.CommandText = sql;
	 connection.Open();
	 return cmd.ExecuteScalar();
	 }
	 }
	 catch (Exception)
	 {
	 return string.Empty;
	 }
	 }
	 #endregion
	 #region 取得表最大Id
	 /// <summary>
	 /// 取得表最大Id
	 /// </summary>
	 /// <param name="tableName"></param>
	 /// <param name="fieldName"></param>
	 /// <param name="con"></param>
	 /// <returns></returns>
	 public static int GetMaxId(string tableName, string fieldName, string con)
	 {
	 string sql = "SELECT NVL(MAX({0}),0)+1 FROM {1}";
	 try
	 {
	 sql = string.Format(sql, fieldName, tableName);
	 int result;
	 Int32.TryParse(ExecuteScalar(sql, con).ToString(), out result);
	 return result;
	 }
	 catch (Exception)
	 {
	 return -1;
	 }
	 }
	 #endregion
	 }
	}
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