Qt使用QSqlDatabase remoeDatabase()连接提示仍在使用解决方案

问题描述

调用QSqlDatabase的removeDatabase函数的时候，出现了如下错误

QSqlDatabasePrivate::removeDatabase: connection '05465461654654' is still in use, all queries will cease to work

官方示例

[static] void QSqlDatabase::removeDatabase(const QString &connectionName)
Removes the database connection connectionName from the list of database connections.
Warning: There should be no open queries on the database connection when this function is called, otherwise a resource leak will occur.
Example:// WRONGQSqlDatabase db = QSqlDatabase::database("sales");QSqlQuery query("SELECT NAME, DOB FROM EMPLOYEES", db);QSqlDatabase::removeDatabase("sales"); // will output a warning// "db" is now a dangling invalid database connection,// "query" contains an invalid result setThe correct way to do it:{QSqlDatabase db = QSqlDatabase::database("sales");QSqlQuery query("SELECT NAME, DOB FROM EMPLOYEES", db);}// Both "db" and "query" are destroyed because they are out of scopeQSqlDatabase::removeDatabase("sales"); // correctTo remove the default connection, which may have been created with a call to addDatabase() not specifying a connection name, you can retrieve the default connection name by calling connectionName() on the database returned by database(). Note that if a default database hasn't been created an invalid database will be returned.
Note: This function is thread-safe.

解决方案

{
QSqlDatabase db = QSqlDatabase::database(“sales”);
QSqlQuery query(“SELECT NAME, DOB FROM EMPLOYEES”, db);
}
// Both “db” and “query” are destroyed because they are out of scope
QSqlDatabase::removeDatabase(“sales”);