数据库操作经典类[DataAccess.cs]

/* * * User: CoderLu * Date: 2010/10/28 * Time: 21:16 * */ using System; using System.Text; using System.Data; using System.Data.SqlClient; using System.Configuration; using System.Collections.Generic; namespace DAL { /// <summary> /// 执行数据基础操作的数据库访问类 /// </summary> public class DataAccess { #region 定义连接字符串connStr /// <summary> /// 定义连接字符串connStr /// </summary> private string connStr = ConfigurationManager.ConnectionStrings["conn"].ToString(); #endregion #region 声明连接对象,暂不实例化 private SqlConnection connection; #endregion #region 默认构造方法,不打开连接 /// <summary> /// 默认构造方法,不打开连接 /// </summary> public DataAccess() { //OpenConn(); } #endregion #region 当连接对象资源被系统回收时，调用关闭连接方法 /// <summary> /// 当连接对象资源被系统回收时，调用关闭连接方法 /// </summary> ~DataAccess() { try { if (this.connection != null) this.connection.Close(); } catch (Exception) { } try { Dispose(); } catch { } } #endregion #region 获得连接字符串,仅用于测试而已 /// <summary> /// 获得连接字符串,仅用于测试而已 /// </summary> /// <returns>连接字符串</returns> public string GetConnString() { if (this.connStr == null) { return "连接还没有打开!"; } else { return this.connStr; } } #endregion #region 打开数据库连接 /// <summary> /// 打开数据库连接 /// </summary> /// <returns>打开成功或原本就已经打开返回true,失败返回false</returns> public bool OpenConn() { bool flag = false; //如果连接尚未创建,将它实例化 if (this.connection == null) { try { this.connection = new SqlConnection(this.connStr); this.connection.Open(); flag = true; } catch (Exception){ } } //如果连接已经关闭,重新打开 else if (this.connection.State.Equals(ConnectionState.Closed)) { try { this.connection.Open(); flag = true; } catch (Exception){ } } else { flag = true; } return flag; } #endregion #region 关闭数据库连接 /// <summary> /// 关闭数据库连接 /// </summary> /// <returns>关闭成功返回true,关闭失败返回false</returns> public bool CloseConn() { try { if (this.connection != null) { this.connection.Close(); } return true; } catch (Exception) { return false; } } #endregion #region 获得连接 /// <summary> /// 获得连接 /// </summary> /// <param name="open">输入true返回已经打开好的连接，false返回对象当前默认状态下的连接</param> /// <returns>返回当前连接对象</returns> public SqlConnection GetConnection(bool open) { if (open == true) this.OpenConn(); return this.connection; } #endregion #region 对SqlCommand的参数进行预先配置 /// <summary> /// 对SqlCommand的参数进行预先配置 /// </summary> /// <param name="cmd">要进行参数配置的SqlCommand对象</param> /// <param name="ct">SqlCommand对象的命令类型</param> /// <param name="cmdTxt">SqlCommand对象的操作语句</param> /// <param name="cmdParms">存储SqlCommand对象参数的数组</param> /// <returns>执行成功返回true,失败返回false</returns> public bool PrepareCommand(SqlCommand cmd, CommandType ct, string cmdTxt, SqlParameter[] cmdParms) { try { this.OpenConn();//打开连接 cmd.Connection = this.GetConnection(false);//将命令与连接相关联 cmd.CommandText = cmdTxt; cmd.CommandType = ct; //遍历将命令参数添加进来 if (cmdParms != null) { foreach (SqlParameter parm in cmdParms) { cmd.Parameters.Add(parm); } } return true; } catch (Exception) { return false; } } #endregion #region 对数据库进行增、删、改操作 /// <summary> /// 执行命令，对数据库进行增、删、改操作 /// </summary> /// <param name="ct">SqlCommand对象的命令类型</param> /// <param name="cmdTxt">SqlCommand对象的操作语句</param> /// <param name="cmdParms">存储SqlCommand对象参数的数组</param> /// <returns>操作执行成功返回true,失败返回false</returns> public int ExecuteNonQuery(CommandType ct, string cmdTxt, SqlParameter[] cmdParms) { try { SqlCommand cmd = new SqlCommand(); this.PrepareCommand(cmd, ct, cmdTxt, cmdParms); int result = cmd.ExecuteNonQuery(); cmd.Parameters.Clear(); return result; } catch (Exception) { return -1; } } /// <summary> /// 执行无参的SQL语句，对数据库进行增、删、改操作 /// </summary> /// <param name="SqlTxt">无参的SQL语句</param> /// <returns>操作执行成功返回true,失败返回false</returns> public int ExecuteNonQuery(string SqlTxt) { try { SqlCommand cmd = new SqlCommand(SqlTxt, this.GetConnection(true)); int result = cmd.ExecuteNonQuery(); return result ; } catch (Exception) { return -1; } } #endregion #region 执行聚合函数命令或SQL语句，返回查询结果 /// <summary> /// 执行聚合函数命令，返回查询结果 /// </summary> /// <param name="ct">SqlCommand对象的命令类型</param> /// <param name="cmdTxt">SqlCommand对象的操作语句</param> /// <param name="cmdParms">存储SqlCommand对象参数的数组</param> /// <returns>查询结果，大于0表示正常，等于0表示查找无结果，等于-1表示执行异常</returns> public int ExecuteScalar(CommandType ct, string cmdTxt, SqlParameter[] cmdParms) { try { SqlCommand cmd = new SqlCommand(); this.PrepareCommand(cmd, ct, cmdTxt, cmdParms); return (Int32)cmd.ExecuteScalar(); } catch (Exception) { return -1; } } /// <summary> /// 执行聚合函数SQL语句，返回查询结果 /// </summary> /// <param name="SqlTxt">SQL查询语句</param> /// <returns>查询结果，大于0表示正常，等于0表示查找无结果，等于-1表示执行异常</returns> public int ExecuteScalar(string SqlTxt) { try { SqlCommand cmd = new SqlCommand(SqlTxt, this.GetConnection(true)); return (Int32)cmd.ExecuteScalar(); } catch (Exception) { return -1; } } #endregion #region 执行查询语句或命令,返回数据阅读器DataReader /// <summary> /// 执行命令,返回数据阅读器DataReader /// </summary> /// <param name="ct">SqlCommand对象的命令类型</param> /// <param name="cmdTxt">SqlCommand对象的操作语句</param> /// <param name="cmdParms">存储SqlCommand对象参数的数组</param> /// <returns>DataReader数据阅读器，执行失败或异常返回null</returns> public SqlDataReader GetDataReader(CommandType ct, string cmdTxt, SqlParameter[] cmdParms) { try { SqlCommand cmd = new SqlCommand(); this.PrepareCommand(cmd, ct, cmdTxt, cmdParms); //将CommandBehavior设置为CloseConnection，如果关闭SqlDataReader 对象，则与它关联的 Connection 对象也将关闭。 return cmd.ExecuteReader(CommandBehavior.CloseConnection); } catch (Exception) { return null; } } /// <summary> /// 执行SQL语句,返回数据阅读器DataReader /// </summary> /// <param name="sqlTxt">不带参数的SQL语句</param> /// <returns>DataReader数据阅读器，执行失败或异常返回null</returns> public SqlDataReader GetDataReader(string sqlTxt) { try { SqlCommand cmd = new SqlCommand(sqlTxt, this.GetConnection(true)); return cmd.ExecuteReader(CommandBehavior.CloseConnection); } catch (Exception) { return null; } } #endregion #region 执行查询命令，返回数据适配器SqlDataAdapter /// <summary> /// 执行查询命令，返回数据适配器SqlDataAdapter /// </summary> /// <param name="ct">SqlCommand对象的命令类型</param> /// <param name="cmdTxt">SqlCommand对象的操作文本</param> /// <param name="cmdParms">存储SqlCommand对象参数的数组</param> /// <param name="option">决定SqlDataAdapter的执行命令类型<br/>1为选择，2为插入，3为删除，4为更新</param> /// <returns>数据适配器SqlDataAdapter，当失败或异常时返回null</returns> public SqlDataAdapter GetDataAdapter(CommandType ct, string cmdTxt, SqlParameter[] cmdParms, int option) { try { SqlDataAdapter sda = new SqlDataAdapter(); SqlCommand cmd = new SqlCommand(); this.PrepareCommand(cmd, ct, cmdTxt, cmdParms); switch (option) { case 1: sda.SelectCommand = cmd; break; case 2: sda.InsertCommand = cmd; break; case 3: sda.DeleteCommand = cmd; break; case 4: sda.UpdateCommand = cmd; break; default: break; } return sda; } catch (Exception) { return null; } } #endregion #region 执行查询命令或SQL语句，返回数据集DataSet /// <summary> /// 执行查询命令，返回数据集DataSet /// </summary> /// <param name="ct">SqlCommand对象的命令类型</param> /// <param name="cmdTxt">SqlCommand对象的操作文本</param> /// <param name="cmdParms">存储SqlCommand对象参数的数组</param> /// <returns>成功查找返回数据集DataSet,异常返回null</returns> public DataSet GetDataSet(CommandType ct, string cmdTxt, SqlParameter[] cmdParms) { try { SqlDataAdapter sda = this.GetDataAdapter(ct, cmdTxt, cmdParms, 1); DataSet ds = new DataSet(); sda.Fill(ds); return ds; } catch (Exception) { return null; } } /// <summary> /// 执行SQL语句，返回数据集DataSet /// </summary> /// <param name="SqlTxt">SQL查询语句</param> /// <returns>成功查找返回数据集DataSet,异常返回null</returns> public DataSet GetDataSet(string SqlTxt) { try { SqlDataAdapter sda = new SqlDataAdapter(SqlTxt, this.connStr); DataSet ds = new DataSet(); sda.Fill(ds); return ds; } catch (Exception) { return null; } } #endregion #region 释放连接对象Connection所占用的系统资源 /// <summary> /// 释放连接对象Connection所占用的系统资源 /// </summary> public void Dispose() { // 确保连接被关闭 try { if (this.connection != null) { this.connection.Dispose(); this.connection = null; } } catch (Exception) { } } #endregion } }