/// <summary> /// SqlHelper提供对于SqlClient常用功能封装提供高性能和高可扩展性的最佳实践 /// </summary> public abstract class SqlHelper { //数据库连接字符串 public static readonly string sqlConnectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString; // 使用哈希表存储缓存后的参数 private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable()); /// <summary> /// 执行不返回的结果的SQL语句，依赖于特定的数据库连接和使用的提供者参数 /// </summary> /// <remarks> /// 示例: /// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, /// "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="connectionString">为SqlConnection指定一个有效的连接字符串</param> /// <param name="commandType">命令类型(stored procedure, text等等)</param> /// <param name="commandText">存储过程名或T-SQL命令</param> /// <param name="commandParameters">SqlParamters数组用于执行命令</param> /// <returns>返回一个整型值得到影响的行数</returns> public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) { SqlCommand cmd = new SqlCommand(); //创建SqlCommand对象实例 //根据传入的连接字符串构建SqlConnection对象 using (SqlConnection conn = new SqlConnection(connectionString)) { //根据传入的SqlParameter以及cmdType和cmdText构建SqlCommand命令 PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters); int val = cmd.ExecuteNonQuery(); //执行SQL并返回受影响的行数 cmd.Parameters.Clear(); //清除参数集合 return val; //返回受影响的行数 } } /// <summary> /// Execute a SqlCommand (that returns no resultset) against an existing database connection /// using the provided parameters. /// </summary> /// <remarks> /// e.g.: /// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="conn">an existing database connection</param> /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param> /// <param name="commandText">the stored procedure name or T-SQL command</param> /// <param name="commandParameters">an array of SqlParamters used to execute the command</param> /// <returns>an int representing the number of rows affected by the command</returns> public static int ExecuteNonQuery(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) { SqlCommand cmd = new SqlCommand(); PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters); int val = cmd.ExecuteNonQuery(); cmd.Parameters.Clear(); return val; } /// <summary> /// Execute a SqlCommand (that returns no resultset) using an existing SQL Transaction /// using the provided parameters. /// </summary> /// <remarks> /// e.g.: /// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="trans">an existing sql transaction</param> /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param> /// <param name="commandText">the stored procedure name or T-SQL command</param> /// <param name="commandParameters">an array of SqlParamters used to execute the command</param> /// <returns>an int representing the number of rows affected by the command</returns> public static int ExecuteNonQuery(SqlTransaction trans, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) { SqlCommand cmd = new SqlCommand(); PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters); int val = cmd.ExecuteNonQuery(); cmd.Parameters.Clear(); return val; } /// <summary> /// Execute a SqlCommand that returns a resultset against the database specified in the connection string /// using the provided parameters. /// </summary> /// <remarks> /// e.g.: /// SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="connectionString">a valid connection string for a SqlConnection</param> /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param> /// <param name="commandText">the stored procedure name or T-SQL command</param> /// <param name="commandParameters">an array of SqlParamters used to execute the command</param> /// <returns>A SqlDataReader containing the results</returns> public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) { SqlCommand cmd = new SqlCommand(); //实例化SqlCommand对象 SqlConnection conn = new SqlConnection(connectionString); //根据连接字符串实例化SqlConnection try { //根据传入的SqlParameter数组及相关SQL参数设置SqlCommand属性 PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters); //执行连接在执行完毕后关闭连接 SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection); cmd.Parameters.Clear(); //清除参数列表 return rdr; //返回SqlDataReader对象 } catch { conn.Close(); //在出现异常时即时关闭连接 throw; //重新抛出异常 } } public static DataTable ExecuteTable(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) { SqlCommand cmd = new SqlCommand(); //实例化SqlCommand对象 //根据指定的连接字符串创建SqlConnection对象 SqlConnection conn = new SqlConnection(connectionString); DataSet ds = null; try { //构建SqlCommand对象的相关属性 PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters); //创建SqlDataAdapter实例，传入SqlCommand对象 SqlDataAdapter dp = new SqlDataAdapter(cmd); ds = new DataSet(); dp.Fill(ds); //执行SQL语句并填充DataSet } catch { conn.Close(); //在出现异常时关闭连接 throw; //抛出异常 } finally { if (conn != null) //无论是否出现异常，在离开时都要关闭连接 conn.Close(); } //返回DataSet的第1个表 return (ds.Tables[0] != null) ? ds.Tables[0] : null; } /// <summary> /// Execute a SqlCommand that returns the first column of the first record against the database specified in the connection string /// using the provided parameters. /// </summary> /// <remarks> /// e.g.: /// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="connectionString">a valid connection string for a SqlConnection</param> /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param> /// <param name="commandText">the stored procedure name or T-SQL command</param> /// <param name="commandParameters">an array of SqlParamters used to execute the command</param> /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns> public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) { SqlCommand cmd = new SqlCommand(); using (SqlConnection connection = new SqlConnection(connectionString)) { PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters); object val = cmd.ExecuteScalar(); cmd.Parameters.Clear(); return val; } } /// <summary> /// Execute a SqlCommand that returns the first column of the first record against an existing database connection /// using the provided parameters. /// </summary> /// <remarks> /// e.g.: /// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="conn">an existing database connection</param> /// <param name="commandType">the CommandType (stored procedure, text, etc.)</param> /// <param name="commandText">the stored procedure name or T-SQL command</param> /// <param name="commandParameters">an array of SqlParamters used to execute the command</param> /// <returns>An object that should be converted to the expected type using Convert.To{Type}</returns> public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) { SqlCommand cmd = new SqlCommand(); PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters); object val = cmd.ExecuteScalar(); cmd.Parameters.Clear(); return val; } /// <summary> /// 添加参数数组到缓存 /// </summary> /// <param name="cacheKey">参数缓存的键</param> /// <param name="cmdParms">要被缓存的SqlParamters数组</param> public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters) { parmCache[cacheKey] = commandParameters; //添加到哈希表 } /// <summary> /// 获取缓存的参数数组 /// </summary> /// <param name="cacheKey">用来查找缓存的参数的键</param> /// <returns>缓存的SqlParamters数组</returns> public static SqlParameter[] GetCachedParameters(string cacheKey) { SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey]; //获取Sql参数数组 //如果当前缓存中并不存在参数数组，则返回null if (cachedParms == null) return null; //实例化新的SqlParameter数组 SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length]; //将cachedParm表中缓存的参数赋给SqlParameter数组 for (int i = 0, j = cachedParms.Length; i < j; i ) clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone(); return clonedParms; //返回SqlCommand数组实例 } /// <summary> /// Prepare a command for execution /// </summary> /// <param name="cmd">SqlCommand object</param> /// <param name="conn">SqlConnection object</param> /// <param name="trans">SqlTransaction object</param> /// <param name="cmdType">Cmd type e.g. stored procedure or text</param> /// <param name="cmdText">Command text, e.g. Select * from Products</param> /// <param name="cmdParms">SqlParameters to use in the command</param> private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms) { if (conn.State != ConnectionState.Open) //判断连接是否打开 conn.Open(); //打开连接 cmd.Connection = conn; //赋给SqlCommand连接对象 cmd.CommandText = cmdText; //指定连接文本 if (trans != null) cmd.Transaction = trans; //是否开启事务 cmd.CommandType = cmdType; //指定命令类型 if (cmdParms != null) { //循环SqlParameter数组，添加到参数集合 foreach (SqlParameter parm in cmdParms) cmd.Parameters.Add(parm); } } }