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最近在做一个项目是.net+MySQL数据库,之前一直用的事SQL Server数据库,基本没接触过MySQL数据库,这次写.net连接MySQL数据库连接时发现个注意事项,写出来给大家做个提醒。 其实C#连接MySQL的方式和连接SQL Server的方式很类似,简单的说一下供大家参考(我连接MySQL数据库是通过ADO.Net): 1.通过ADO.Net连接数据要用到MySql.Data.dll 这个类库,比较重要的一点是:
MySql.Data.dll的版本有很多,程序中试用时,用到的MySql.Data.dll类库的版本要大于 MySQL数据库的版本,比如MySQL数据库的版本为:5.0 ,那么MySql.Data.dll的版本要大于5.0,用6.0都可以。
这一点为个人验证发现,之前根据网上的代码,都写好但总是报错,报各种错误,后台几番折腾,后台发现更换了MySql.Data.dll版本好了,所以有所结论,不知道是否有误,有误请大家指出
2、关于Webconfig的配置
<add key="ConnectionString" value="server=192.168.1.102;database=test;uid=root;pwd=123456; "/> 我用的6.0的类库连接MySQL数据时,配置是不用写端口的,不知道是不是类库特有的特性 3、发一下我的数据库操作类(采用动软生成): using System; using System.Collections; using System.Collections.Specialized; using System.Data; using MySql.Data.MySqlClient; using System.Configuration; using System.Data.Common; using System.Collections.Generic; namespace Maticsoft.DBUtility { /// <summary> /// 数据访问抽象基础类 /// Copyright (C) Maticsoft /// </summary> public abstract class DbHelperMySQL { //数据库连接字符串(web.config来配置),可以动态更改connectionString支持多数据库. public static string connectionString =ConfigurationManager.AppSettings["ConnectionString"]; public DbHelperMySQL() { } #region 公用方法 /// <summary> /// 得到最大值 /// </summary> /// <param name="FieldName"></param> /// <param name="TableName"></param> /// <returns></returns> public static int GetMaxID(string FieldName, string TableName) { string strsql = "select max(" + FieldName + ")+1 from " + TableName; object obj = GetSingle(strsql); if (obj == null) { return 1; } else { return int.Parse(obj.ToString()); } } /// <summary> /// 是否存在 /// </summary> /// <param name="strSql"></param> /// <returns></returns> public static bool Exists(string strSql) { object obj = GetSingle(strSql); int cmdresult; if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value))) { cmdresult = 0; } else { cmdresult = int.Parse(obj.ToString()); } if (cmdresult == 0) { return false; } else { return true; } } /// <summary> /// 是否存在(基于MySqlParameter) /// </summary> /// <param name="strSql"></param> /// <param name="cmdParms"></param> /// <returns></returns> public static bool Exists(string strSql, params MySqlParameter[] cmdParms) { object obj = GetSingle(strSql, cmdParms); int cmdresult; if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value))) { cmdresult = 0; } else { cmdresult = int.Parse(obj.ToString()); } if (cmdresult == 0) { return false; } else { return true; } } #endregion #region 执行简单SQL语句 /// <summary> /// 执行SQL语句,返回影响的记录数 /// </summary> /// <param name="SQLString">SQL语句</param> /// <returns>影响的记录数</returns> public static int ExecuteSql(string SQLString) { using (MySqlConnection connection = new MySqlConnection(connectionString)) { using (MySqlCommand cmd = new MySqlCommand(SQLString, connection)) { try { connection.Open(); int rows = cmd.ExecuteNonQuery(); return rows; } catch (MySql.Data.MySqlClient.MySqlException e) { connection.Close(); throw e; } } } } public static int ExecuteSqlByTime(string SQLString, int Times) { using (MySqlConnection connection = new MySqlConnection(connectionString)) { using (MySqlCommand cmd = new MySqlCommand(SQLString, connection)) { try { connection.Open(); cmd.CommandTimeout = Times; int rows = cmd.ExecuteNonQuery(); return rows; } catch (MySql.Data.MySqlClient.MySqlException e) { connection.Close(); throw e; } } } } /// <summary> /// 执行MySql和Oracle滴混合事务 /// </summary> /// <param name="list">SQL命令行列表</param> /// <param name="oracleCmdSqlList">Oracle命令行列表</param> /// <returns>执行结果 0-由于SQL造成事务失败 -1 由于Oracle造成事务失败 1-整体事务执行成功</returns> public static int ExecuteSqlTran(List<CommandInfo> list, List<CommandInfo> oracleCmdSqlList) { using (MySqlConnection conn = new MySqlConnection(connectionString)) { conn.Open(); MySqlCommand cmd = new MySqlCommand(); cmd.Connection = conn; MySqlTransaction tx = conn.BeginTransaction(); cmd.Transaction = tx; try { foreach (CommandInfo myDE in list) { string cmdText = myDE.CommandText; MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Parameters; PrepareCommand(cmd, conn, tx, cmdText, cmdParms); if (myDE.EffentNextType == EffentNextType.SolicitationEvent) { if (myDE.CommandText.ToLower().IndexOf("count(") == -1) { tx.Rollback(); throw new Exception("违背要求"+myDE.CommandText+"必须符合select count(..的格式"); //return 0; } object obj = cmd.ExecuteScalar(); bool isHave = false; if (obj == null && obj == DBNull.Value) { isHave = false; } isHave = Convert.ToInt32(obj) > 0; if (isHave) { //引发事件 myDE.OnSolicitationEvent(); } } if (myDE.EffentNextType == EffentNextType.WhenHaveContine || myDE.EffentNextType == EffentNextType.WhenNoHaveContine) { if (myDE.CommandText.ToLower().IndexOf("count(") == -1) { tx.Rollback(); throw new Exception("SQL:违背要求" + myDE.CommandText + "必须符合select count(..的格式"); //return 0; } object obj = cmd.ExecuteScalar(); bool isHave = false; if (obj == null && obj == DBNull.Value) { isHave = false; } isHave = Convert.ToInt32(obj) > 0; if (myDE.EffentNextType == EffentNextType.WhenHaveContine && !isHave) { tx.Rollback(); throw new Exception("SQL:违背要求" + myDE.CommandText + "返回值必须大于0"); //return 0; } if (myDE.EffentNextType == EffentNextType.WhenNoHaveContine && isHave) { tx.Rollback(); throw new Exception("SQL:违背要求" + myDE.CommandText + "返回值必须等于0"); //return 0; } continue; } int val = cmd.ExecuteNonQuery(); if (myDE.EffentNextType == EffentNextType.ExcuteEffectRows && val == 0) { tx.Rollback(); throw new Exception("SQL:违背要求" + myDE.CommandText + "必须有影响行"); //return 0; } cmd.Parameters.Clear(); } string oraConnectionString = PubConstant.GetConnectionString("ConnectionStringPPC"); bool res = OracleHelper.ExecuteSqlTran(oraConnectionString, oracleCmdSqlList); if (!res) { tx.Rollback(); throw new Exception("执行失败"); // return -1; } tx.Commit(); return 1; } catch (MySql.Data.MySqlClient.MySqlException e) { tx.Rollback(); throw e; } catch (Exception e) { tx.Rollback(); throw e; } } } /// <summary> /// 执行多条SQL语句,实现数据库事务。 /// </summary> /// <param name="SQLStringList">多条SQL语句</param> public static int ExecuteSqlTran(List<String> SQLStringList) { using (MySqlConnection conn = new MySqlConnection(connectionString)) { conn.Open(); MySqlCommand cmd = new MySqlCommand(); cmd.Connection = conn; MySqlTransaction tx = conn.BeginTransaction(); cmd.Transaction = tx; try { int count = 0; for (int n = 0; n < SQLStringList.Count; n++) { string strsql = SQLStringList[n]; if (strsql.Trim().Length > 1) { cmd.CommandText = strsql; count += cmd.ExecuteNonQuery(); } } tx.Commit(); return count; } catch { tx.Rollback(); return 0; } } } /// <summary> /// 执行带一个存储过程参数的的SQL语句。 /// </summary> /// <param name="SQLString">SQL语句</param> /// <param name="content">参数内容,比如一个字段是格式复杂的文章,有特殊符号,可以通过这个方式添加</param> /// <returns>影响的记录数</returns> public static int ExecuteSql(string SQLString, string content) { using (MySqlConnection connection = new MySqlConnection(connectionString)) { MySqlCommand cmd = new MySqlCommand(SQLString, connection); MySql.Data.MySqlClient.MySqlParameter myParameter = new MySql.Data.MySqlClient.MySqlParameter("@content", SqlDbType.NText); myParameter.Value = content; cmd.Parameters.Add(myParameter); try { connection.Open(); int rows = cmd.ExecuteNonQuery(); return rows; } catch (MySql.Data.MySqlClient.MySqlException e) { throw e; } finally { cmd.Dispose(); connection.Close(); } } } /// <summary> /// 执行带一个存储过程参数的的SQL语句。 /// </summary> /// <param name="SQLString">SQL语句</param> /// <param name="content">参数内容,比如一个字段是格式复杂的文章,有特殊符号,可以通过这个方式添加</param> /// <returns>影响的记录数</returns> public static object ExecuteSqlGet(string SQLString, string content) { using (MySqlConnection connection = new MySqlConnection(connectionString)) { MySqlCommand cmd = new MySqlCommand(SQLString, connection); MySql.Data.MySqlClient.MySqlParameter myParameter = new MySql.Data.MySqlClient.MySqlParameter("@content", SqlDbType.NText); myParameter.Value = content; cmd.Parameters.Add(myParameter); try { connection.Open(); object obj = cmd.ExecuteScalar(); if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value))) { return null; } else { return obj; } } catch (MySql.Data.MySqlClient.MySqlException e) { throw e; } finally { cmd.Dispose(); connection.Close(); } } } /// <summary> /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例) /// </summary> /// <param name="strSQL">SQL语句</param> /// <param name="fs">图像字节,数据库的字段类型为image的情况</param> /// <returns>影响的记录数</returns> public static int ExecuteSqlInsertImg(string strSQL, byte[] fs) { using (MySqlConnection connection = new MySqlConnection(connectionString)) { MySqlCommand cmd = new MySqlCommand(strSQL, connection); MySql.Data.MySqlClient.MySqlParameter myParameter = new MySql.Data.MySqlClient.MySqlParameter("@fs", SqlDbType.Image); myParameter.Value = fs; cmd.Parameters.Add(myParameter); try { connection.Open(); int rows = cmd.ExecuteNonQuery(); return rows; } catch (MySql.Data.MySqlClient.MySqlException e) { throw e; } finally { cmd.Dispose(); connection.Close(); } } } /// <summary> /// 执行一条计算查询结果语句,返回查询结果(object)。 /// </summary> /// <param name="SQLString">计算查询结果语句</param> /// <returns>查询结果(object)</returns> public static object GetSingle(string SQLString) { using (MySqlConnection connection = new MySqlConnection(connectionString)) { using (MySqlCommand cmd = new MySqlCommand(SQLString, connection)) { try { connection.Open(); object obj = cmd.ExecuteScalar(); if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value))) { return null; } else { return obj; } } catch (MySql.Data.MySqlClient.MySqlException e) { connection.Close(); throw e; } } } } public static object GetSingle(string SQLString, int Times) { using (MySqlConnection connection = new MySqlConnection(connectionString)) { using (MySqlCommand cmd = new MySqlCommand(SQLString, connection)) { try { connection.Open(); cmd.CommandTimeout = Times; object obj = cmd.ExecuteScalar(); if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value))) { return null; } else { return obj; } } catch (MySql.Data.MySqlClient.MySqlException e) { connection.Close(); throw e; } } } } /// <summary> /// 执行查询语句,返回MySqlDataReader ( 注意:调用该方法后,一定要对MySqlDataReader进行Close ) /// </summary> /// <param name="strSQL">查询语句</param> /// <returns>MySqlDataReader</returns> public static MySqlDataReader ExecuteReader(string strSQL) { MySqlConnection connection = new MySqlConnection(connectionString); MySqlCommand cmd = new MySqlCommand(strSQL, connection); try { connection.Open(); MySqlDataReader myReader = cmd.ExecuteReader(CommandBehavior.CloseConnection); return myReader; } catch (MySql.Data.MySqlClient.MySqlException e) { throw e; } } /// <summary> /// 执行查询语句,返回DataSet /// </summary> /// <param name="SQLString">查询语句</param> /// <returns>DataSet</returns> public static DataSet Query(string SQLString) { using (MySqlConnection connection = new MySqlConnection(connectionString)) { DataSet ds = new DataSet(); try { connection.Open(); MySqlDataAdapter command = new MySqlDataAdapter(SQLString, connection); command.Fill(ds, "ds"); } catch (MySql.Data.MySqlClient.MySqlException ex) { throw new Exception(ex.Message); } return ds; } } public static DataSet Query(string SQLString, int Times) { using (MySqlConnection connection = new MySqlConnection(connectionString)) { DataSet ds = new DataSet(); try { connection.Open(); MySqlDataAdapter command = new MySqlDataAdapter(SQLString, connection); command.SelectCommand.CommandTimeout = Times; command.Fill(ds, "ds"); } catch (MySql.Data.MySqlClient.MySqlException ex) { throw new Exception(ex.Message); } return ds; } } #endregion #region 执行带参数的SQL语句 /// <summary> /// 执行SQL语句,返回影响的记录数 /// </summary> /// <param name="SQLString">SQL语句</param> /// <returns>影响的记录数</returns> public static int ExecuteSql(string SQLString, params MySqlParameter[] cmdParms) { using (MySqlConnection connection = new MySqlConnection(connectionString)) { using (MySqlCommand cmd = new MySqlCommand()) { try { PrepareCommand(cmd, connection, null, SQLString, cmdParms); int rows = cmd.ExecuteNonQuery(); cmd.Parameters.Clear(); return rows; } catch (MySql.Data.MySqlClient.MySqlException e) { throw e; } } } } /// <summary> /// 执行多条SQL语句,实现数据库事务。 /// </summary> /// <param name="SQLStringList">SQL语句的哈希表(key为sql语句,value是该语句的MySqlParameter[])</param> public static void ExecuteSqlTran(Hashtable SQLStringList) { using (MySqlConnection conn = new MySqlConnection(connectionString)) { conn.Open(); using (MySqlTransaction trans = conn.BeginTransaction()) { MySqlCommand cmd = new MySqlCommand(); try { //循环 foreach (DictionaryEntry myDE in SQLStringList) { string cmdText = myDE.Key.ToString(); MySqlParameter[] cmdParms = (MySqlParameter[])myDE.Value; PrepareCommand(cmd, conn, trans, cmdText, cmdParms); int val = cmd.ExecuteNonQuery(); cmd.Parameters.Clear(); } trans.Commit(); } catch { trans.Rollback(); throw; } } } } /// <summary> /// 执行多条SQL语句,实现数据库事务。 /// </summary> /// <param name="SQLStringList">SQL语句的哈希表(key为sql语句,value是该语句的MySqlParameter[])</param> public static int ExecuteSqlTran(System.Collections.Ge |
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