using System.Configuration;using System.Data;using System.Data.SqlClient;using System.Collections; 
/// <summary>
/// SqlHelper类提供很高的数据访问性能, /// 使用SqlClient类的通用定义.
/// </summary> public abstract class SqlHelper { //定义数据库连接串 public static readonly string ConnectionStringLocalTransaction = ConfigurationManager.ConnectionStrings["ExamConnectionString"].ConnectionString; //public static readonly string ConnectionStringInventoryDistributedTransaction = ConfigurationManager.ConnectionStrings["SQLConnString1"].ConnectionString; //public static readonly string ConnectionStringOrderDistributedTransaction = ConfigurationManager.ConnectionStrings["SQLConnString3"].ConnectionString; //public static readonly string ConnectionStringProfile = ConfigurationManager.ConnectionStrings["SQLProfileConnString"].ConnectionString; // 存贮Cache缓存的Hashtable集合 private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable()); 
/// <summary>
/// 使用连接字符串，执行一个SqlCommand命令（没有记录返回） /// 使用提供的参数集. /// </summary> /// <remarks> /// 示例: 
/// int result = ExecuteNonQuery(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="connectionString">一个有效的SqlConnection连接串</param> /// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param> /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param> /// <param name="commandParameters">执行命令的参数集</param> /// <returns>受此命令影响的行数</returns> public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) { SqlCommand cmd = new SqlCommand(); using (SqlConnection conn = new SqlConnection(connectionString)) { PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters); int val = cmd.ExecuteNonQuery(); cmd.Parameters.Clear(); return val; } } /// <summary> /// 在一个存在的连接上执行数据库的命令操作 /// 使用提供的参数集. /// </summary> /// <remarks> /// e.g.: /// int result = ExecuteNonQuery(connection, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="conn">一个存在的数据库连接对象</param> /// <param name="commandType">命令类型CommandType (stored procedure, text, etc.)</param> /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param> /// <param name="commandParameters">执行命令的参数集</param> /// <returns>受此命令影响的行数</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> /// 在一个事务的连接上执行数据库的命令操作 /// 使用提供的参数集. /// </summary> /// <remarks> /// e.g.: /// int result = ExecuteNonQuery(trans, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="trans">一个存在的事务</param> /// <param name="commandType">命令类型CommandType (stored procedure, text, etc.)</param> /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param> /// <param name="commandParameters">执行命令的参数集</param> /// <returns>受此命令影响的行数</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> /// 在一个连接串上执行一个命令，返回一个SqlDataReader对象 /// 使用提供的参数. /// </summary> /// <remarks> /// e.g.: /// SqlDataReader r = ExecuteReader(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="connectionString">一个有效的SqlConnection连接串</param> /// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param> /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param> /// <param name="commandParameters">执行命令的参数集</param> /// <returns>一个结果集对象SqlDataReader</returns> public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) { SqlCommand cmd = new SqlCommand(); SqlConnection conn = new SqlConnection(connectionString); // 如果不存在要查询的对象，则发生异常 // 连接要关闭 // CommandBehavior.CloseConnection在异常时不发生作用 try { PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters); SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection); cmd.Parameters.Clear(); return rdr; } catch { conn.Close(); throw; } } /// <summary> /// 在一个连接串上执行一个命令，返回表中第一行，第一列的值 /// 使用提供的参数. /// </summary> /// <remarks> /// e.g.: /// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="connectionString">一个有效的SqlConnection连接串</param> /// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param> /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param> /// <param name="commandParameters">执行命令的参数集</param> /// <returns>返回的对象，在使用时记得类型转换</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> /// 在一个连接上执行一个命令，返回表中第一行，第一列的值 /// 使用提供的参数. /// </summary> /// <remarks> /// e.g.: /// Object obj = ExecuteScalar(connString, CommandType.StoredProcedure, "PublishOrders", new SqlParameter("@prodid", 24)); /// </remarks> /// <param name="connectionString">一个有效的SqlConnection连接</param> /// <param name="commandType">命令类型CommandType(stored procedure, text, etc.)</param> /// <param name="commandText">存贮过程名称或是一个T-SQL语句串</param> /// <param name="commandParameters">执行命令的参数集</param> /// <returns>返回的对象，在使用时记得类型转换</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> /// 在缓存中添加参数数组 /// </summary> /// <param name="cacheKey">参数的Key</param> /// <param name="cmdParms">参数数组</param> public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters) { parmCache[cacheKey] = commandParameters; } /// <summary> /// 提取缓存的参数数组 /// </summary> /// <param name="cacheKey">查找缓存的key</param> /// <returns>返回被缓存的参数数组</returns> public static SqlParameter[] GetCachedParameters(string cacheKey) { SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey]; if (cachedParms == null) return null; SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length]; for (int i = 0, j = cachedParms.Length; i < j; i++) clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone(); return clonedParms; } /// <summary> /// 提供一个SqlCommand对象的设置 /// </summary> /// <param name="cmd">SqlCommand对象</param> /// <param name="conn">SqlConnection 对象</param> /// <param name="trans">SqlTransaction 对象</param> /// <param name="cmdType">CommandType 如存贮过程，T-SQL</param> /// <param name="cmdText">存贮过程名或查询串</param> /// <param name="cmdParms">命令中用到的参数集</param> private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms) { if (conn.State != ConnectionState.Open) conn.Open(); cmd.Connection = conn; cmd.CommandText = cmdText; if (trans != null) cmd.Transaction = trans; cmd.CommandType = cmdType; if (cmdParms != null) { foreach (SqlParameter parm in cmdParms) cmd.Parameters.Add(parm); } } }