1. 解释“mysql the connection is already open”错误信息的含义 通常,“mysql the connection is already open”这一错误信息并非MySQL官方错误消息的直接表述。MySQL本身在处理连接时,更多的是通过状态码或特定的错误消息来反馈问题,如“Too many connections”(连接数过多)或“Can't connect to MySQL server on...
1 如果用完不关闭,最有可能的错误是从连接池中获取连接超时,而你这个错误最有可能的原因,是对同一个实例调用了两次 Open。 Launcher | 园豆:45050 (高人七级) | 2015-04-24 15:23 同一个实例调用2次?意思是并发同时调用一个连接么? 支持(0) 反对(0) 土匪吃黄瓜 | 园豆:2 (初学一级) | 2015-0...
ContainsGenericParameters is true. Cannot create folder because a file or directory with the same name already exists Cannot create the instance of Abstract or interface 'syste..data.common.dbconnection Cannot delete mdf file after it has been accessed once Cannot find or open the PDB file ...
System.InvalidOperationException: The connection is already open. at MySql.Data.MySqlClient.Interceptors.ExceptionInterceptor.Throw(Exception exception) at MySql.Data.MySqlClient.MySqlConnection.Throw(Exception ex) at MySql.Data.MySqlClient.MySqlConnection.Open() at System.Data.Common.DbConnection.OpenAsync...
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当使用MySql数据库时,第二次查询时报错“There is already an open DataReader associated with this Connection which must be closed”。 1,由于MySqlConnection(数据库连接)的对象是全局变量引用,虽然可以通过关闭数据库连接清除报警,但占用资源较大。--未采用...
出现这个报错尝试 加一个异常处理关闭全部浏览器在打开
Uses of this class follow a pattern: Obtain a new HttpURLConnection by calling URL#openConnection() URL.openConnection() and casting the result to HttpURLConnection. Prepare the request. The primary property of a request is its URI. Request headers may also include metadata such as credential...
If aSqlExceptionis generated by the method executing aSqlCommand, theSqlConnectionremains open when the severity level is 19 or less. When the severity level is 20 or greater, the server ordinarily closes theSqlConnection. However, the user can reopen the connection and continue. ...
For those of you who don’t know of TechDays Online already, it is a ‘pop up TV show’ MSFT UK live... Date: 06/04/2018 Microsoft HoloLens in academia unlocking new surgical procedures Last week we had a great event at Microsoft London with a number of UK Academic institutions. Thes...