针对SQLServer数据库的通用访问类

 Web.config中代码

<configuration>
  <connectionStrings>
    <add name="connString" connectionString="Server=数据库服务;DataBase=数据库名称;Uid=数据库登录名用户;Pwd=数据库登录密码"/>
  </connectionStrings>
</configuration>

 

  现在我们先建一个SQLHelper类，用来对数据库的操作

  代码如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Configuration;

namespace DAL
{
    /// <summary>
    /// 针对SQLServer数据库的通用访问类
    /// </summary>
    public class SQLHelper
    {

        //封装数据库连接字符串
        private static string connString = ConfigurationManager.ConnectionStrings["connString"].ToString();

        #region 封装格式化SQL语句执行的各种方法

        public static int Update(string sql)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand(sql, conn);
            try
            {
                conn.Open();
                return cmd.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                //将异常信息写入日志
                string errorInfo = "调用public static int Update(string sql)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
            finally
            {
                conn.Close();
            }
        }
        public static object GetSingleResult(string sql)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand(sql, conn);
            try
            {
                conn.Open();
                return cmd.ExecuteScalar();
            }
            catch (Exception ex)
            {
                //将异常信息写入日志              
                string errorInfo = "调用public static object  GetSingleResult(string sql)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
            finally
            {
                conn.Close();
            }
        }
        public static SqlDataReader GetReader(string sql)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand(sql, conn);
            try
            {
                conn.Open();
                return cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }
            catch (Exception ex)
            {
                conn.Close();
                //将异常信息写入日志              
                string errorInfo = "调用SqlDataReader GetReader(string sql)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
        }
        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;
            }
            catch (Exception ex)
            {
                //将异常信息写入日志              
                string errorInfo = "调用  public static DataSet GetDataSet(string sql)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
            finally
            {
                conn.Close();
            }
        }
        public static bool UpdateByTran(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 sql in sqlList)
                {
                    cmd.CommandText = sql;
                    cmd.ExecuteNonQuery();
                }
                cmd.Transaction.Commit();//提交事务
                return true;
            }
            catch (Exception ex)
            {
                if (cmd.Transaction != null)
                {
                    cmd.Transaction.Rollback();//回滚事务
                }
                string errorInfo = "调用UpdateByTran(List<string> sqlList)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
            finally
            {
                if (cmd.Transaction != null)
                {
                    cmd.Transaction = null;//清空事务
                }
                conn.Close();
            }
        }

        #endregion

        #region 封装带参数SQL语句执行的各种方法

        public static int Update(string sql, SqlParameter[] param)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand(sql, conn);
            try
            {
                conn.Open();
                cmd.Parameters.AddRange(param);//封装参数
                return cmd.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                string errorInfo = "调用 public static int Update(string sql,SqlParameter[] param)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw ex;
            }
            finally
            {
                conn.Close();
            }
        }
        public static object GetSingleResult(string sql, SqlParameter[] param)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand(sql, conn);
            try
            {
                conn.Open();
                cmd.Parameters.AddRange(param);//封装参数
                return cmd.ExecuteScalar();
            }
            catch (Exception ex)
            {
                //将异常信息写入日志              
                string errorInfo = "调用 public static object GetSingleResult(string sql, SqlParameter[] param)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
            finally
            {
                conn.Close();
            }
        }
        public static SqlDataReader GetReader(string sql, SqlParameter[] param)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand(sql, conn);
            try
            {
                conn.Open();
                cmd.Parameters.AddRange(param);//封装参数
                return cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }
            catch (Exception ex)
            {
                conn.Close();
                //将异常信息写入日志              
                string errorInfo = "调用 public static SqlDataReader GetReader(string sql, SqlParameter[] param)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
        }
        /// <summary>
        /// 启用事务提交多条带参数的SQL语句
        /// </summary>
        /// <param name="mainSql">主表SQL语句</param>
        /// <param name="mainParam">主表SQL语句对应的参数</param>
        /// <param name="detailSql">明细表SQL语句</param>
        /// <param name="detailParam">明细表SQL语句对应的参数数组集合</param>
        /// <returns>返回事务是否执行成功</returns>
        public static bool UpdateByTran(string mainSql, SqlParameter[] mainParam,
            string detailSql, List<SqlParameter[]> detailParam)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            try
            {
                conn.Open();
                cmd.Transaction = conn.BeginTransaction();//开启事务
                if (mainSql != null && mainSql.Length != 0)
                {
                    cmd.CommandText = mainSql;
                    cmd.Parameters.AddRange(mainParam);
                    cmd.ExecuteNonQuery();
                }
                foreach (SqlParameter[] param in detailParam)
                {
                    cmd.CommandText = detailSql;
                    cmd.Parameters.Clear();//必须要清除以前的参数
                    cmd.Parameters.AddRange(param);
                    cmd.ExecuteNonQuery();
                }
                cmd.Transaction.Commit();//提交事务
                return true;
            }
            catch (Exception ex)
            {
                if (cmd.Transaction != null)
                {
                    cmd.Transaction.Rollback();//回滚事务
                }
                string errorInfo = "调用  public static bool UpdateByTran(string mainSql, SqlParameter[] mainParam, string detailSql, List<SqlParameter[]> detailParam)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
            finally
            {
                if (cmd.Transaction != null)
                {
                    cmd.Transaction = null;//清空事务
                }
                conn.Close();
            }
        }

        #endregion

        #region 封装调用存储过程执行的各种方法

        public static int UpdateByProcedure(string spName, SqlParameter[] param)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand(spName, conn);
            try
            {
                conn.Open();
                cmd.CommandType = CommandType.StoredProcedure;//声明当前操作是存储过程
                cmd.Parameters.AddRange(param);//封装参数
                return cmd.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                string errorInfo = "调用 public static int UpdateByProcedure(string spName, SqlParameter[] param)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
            finally
            {
                conn.Close();
            }
        }
        public static object GetSingleResultByProcedure(string spName, SqlParameter[] param)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand(spName, conn);
            try
            {
                conn.Open();
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.AddRange(param);//封装参数
                return cmd.ExecuteScalar();
            }
            catch (Exception ex)
            {
                //将异常信息写入日志              
                string errorInfo = "调用 public static object GetSingleResult(string sql, SqlParameter[] param)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
            finally
            {
                conn.Close();
            }
        }
        public static SqlDataReader GetReaderByProcedure(string spName, SqlParameter[] param)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand(spName, conn);
            try
            {
                conn.Open();
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.Parameters.AddRange(param);//封装参数
                return cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }
            catch (Exception ex)
            {
                conn.Close();
                //将异常信息写入日志              
                string errorInfo = "调用 public static SqlDataReader GetReader(string sql, SqlParameter[] param)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
        }
        /// <summary>
        /// 启用事务调用带参数的存储过程
        /// </summary>
        /// <param name="procedureName">存储过程名称</param>
        /// <param name="paramArray">存储过程参数数组集合</param>
        /// <returns>返回基于事务的存储过程调用是否成功</returns>
        public static bool UpdateByTran(string procedureName, List<SqlParameter[]> paramArray)
        {
            SqlConnection conn = new SqlConnection(connString);
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            try
            {
                conn.Open();
                cmd.CommandType = CommandType.StoredProcedure;//声明当前操作是调用存储过程
                cmd.CommandText = procedureName;
                cmd.Transaction = conn.BeginTransaction();//开启事务             
                foreach (SqlParameter[] param in paramArray)
                {
                    cmd.Parameters.Clear();
                    cmd.Parameters.AddRange(param);
                    cmd.ExecuteNonQuery();
                }
                cmd.Transaction.Commit();//提交事务
                return true;
            }
            catch (Exception ex)
            {
                if (cmd.Transaction != null)
                {
                    cmd.Transaction.Rollback();//回滚事务
                }
                string errorInfo = "调用 public static bool UpdateByTran(string procedureName,List<SqlParameter[]>paramArray)方法时发生错：" + ex.Message;
                WriteLog(errorInfo);
                throw new Exception(errorInfo);
            }
            finally
            {
                if (cmd.Transaction != null)
                {
                    cmd.Transaction = null;//清空事务
                }
                conn.Close();
            }
        }

        #endregion

        #region 其他方法

        private static void WriteLog(string log)
        {
            FileStream fs = new FileStream("sqlhelper.log", FileMode.Append);
            StreamWriter sw = new StreamWriter(fs);
            sw.WriteLine(DateTime.Now.ToString() + "   " + log);
            sw.Close();
            fs.Close();
        }

        #endregion
    }
}

 WriteLog方法主要是用来记录错误日志，把错误已文本的方式存储在根目录里方便维护，

 同时在SQLHelper要引用System.Configuration命名空间，不然的话会报错。