using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;using System.Data;
using System.Data.SqlClient;
using System.Configuration;namespace StudentManager.Dao
{/// <summary>///  通用数据访问类/// </summary>class SQLHelper{private static readonly string connString = "Server=.;DataBase=StudentManager;Uid=sa;Pwd=password01!";// public static readonly string connString = ConfigurationManager.ConnectionStrings["connString"].ToString();//private static readonly string connString =//    Common.StringSecurity.DESDecrypt(ConfigurationManager.ConnectionStrings["connString"].ToString());#region 执行格式化的SQL语句/// <summary>/// 执行增、删、改（insert/update/delete）/// </summary>/// <param name="sql"></param>/// <returns></returns>public static int Update(string sql){SqlConnection conn = new SqlConnection(connString);SqlCommand cmd = new SqlCommand(sql, conn);try{conn.Open();int result = cmd.ExecuteNonQuery();return result;}catch (Exception ex){throw ex;}finally{conn.Close();}}/// <summary>/// 执行单一结果查询（select）/// </summary>/// <param name="sql"></param>/// <returns></returns>public static object GetSingleResult(string sql){SqlConnection conn = new SqlConnection(connString);SqlCommand cmd = new SqlCommand(sql, conn);try{conn.Open();object result = cmd.ExecuteScalar();return result;}catch (Exception ex){throw ex;}finally{conn.Close();}}/// <summary>/// 执行多结果查询（select）/// </summary>/// <param name="sql"></param>/// <returns></returns>public static SqlDataReader GetReader(string sql){SqlConnection conn = new SqlConnection(connString);SqlCommand cmd = new SqlCommand(sql, conn);try{conn.Open();SqlDataReader objReader =cmd.ExecuteReader(CommandBehavior.CloseConnection);return objReader;}catch (Exception ex){conn.Close();throw ex;}}/// <summary>/// 执行返回数据集的查询/// </summary>/// <param name="sql"></param>/// <returns></returns>public static DataSet GetDataSet(string sql){SqlConnection conn = new SqlConnection(connString);SqlCommand cmd = new SqlCommand(sql, conn);SqlDataAdapter da = new SqlDataAdapter(cmd); //创建数据适配器对象DataSet ds = new DataSet();//创建一个内存数据集try{conn.Open();da.Fill(ds);  //使用数据适配器填充数据集return ds;  //返回数据集
            }catch (Exception ex){throw ex;}finally{conn.Close();}}#endregion#region 带参数的SQL语句public static int Update(string sql, SqlParameter[] parameter){SqlConnection conn = new SqlConnection(connString);SqlCommand cmd = new SqlCommand(sql, conn);try{conn.Open();cmd.Parameters.AddRange(parameter);//为Command对象添加参数//foreach (SqlParameter  item in parameter)//{//    cmd.Parameters.Add(item);//}int result = cmd.ExecuteNonQuery();return result;}catch (Exception ex){throw ex;}finally{conn.Close();}}#endregion#region 调用存储过程public static int UpdateByProcedure(string procedureName, SqlParameter[] param){SqlConnection conn = new SqlConnection(connString);SqlCommand cmd = new SqlCommand();cmd.Connection = conn;try{conn.Open();cmd.CommandType = CommandType.StoredProcedure;//声明当前要执行的是存储过程cmd.CommandText = procedureName;//commandText只需要赋值存储过程名称即可cmd.Parameters.AddRange(param);//添加存储过程的参数int result = cmd.ExecuteNonQuery();return result;}catch (Exception ex){throw ex;}finally{conn.Close();}}/// <summary>/// 执行多结果查询（select）/// </summary>/// <param name="sql"></param>/// <returns></returns>public static SqlDataReader GetReaderByProcedure(string procedureName, SqlParameter[] param){SqlConnection conn = new SqlConnection(connString);SqlCommand cmd = new SqlCommand();cmd.Connection = conn;try{conn.Open();cmd.CommandType = CommandType.StoredProcedure;cmd.CommandText = procedureName;cmd.Parameters.AddRange(param);SqlDataReader objReader =cmd.ExecuteReader(CommandBehavior.CloseConnection);return objReader;}catch (Exception ex){conn.Close();throw ex;}}#endregion#region 启用事务/// <summary>/// 启用事务执行多条SQL语句/// </summary>      /// <param name="sqlList">SQL语句列表</param>      /// <returns></returns>public static bool ExecSQLByTran(List<string> sqlList){SqlConnection conn = new SqlConnection(connString);SqlCommand cmd = new SqlCommand();cmd.Connection = conn;try{conn.Open();cmd.Transaction = conn.BeginTransaction();   //开启事务foreach (string itemSql in sqlList)//循环提交SQL语句
                {cmd.CommandText = itemSql;cmd.ExecuteNonQuery();}cmd.Transaction.Commit();  //提交事务(同时自动清除事务)return true;}catch (Exception ex){if (cmd.Transaction != null)cmd.Transaction.Rollback();//回滚事务(同时自动清除事务)throw new Exception("调用事务方法时出现错误：" + ex.Message);}finally{if (cmd.Transaction != null)cmd.Transaction = null;conn.Close();}}#endregion}
}