Question

我在c＃中使用针对Firebird的dot net提供程序运行了许多SQL命令。具体来说，我改变数据库架构，进行数据更新等。

作为我处理的一部分，我创建了一个新表，运行查询以从旧表中复制数据，然后删除旧表。

当我这样做时，firebird会生成错误：

不成功的元数据更新对象正在使用

我已经完成了一些工作，并且似乎就像复制数据的查询一样，并没有被清除＆＃34;我们还是别的什么。我的意思是当我在我的c＃执行暂停时检查Firebird中的监控表时，我看到MON$STATEMENTS表中的查询为非活动状态。这是在我运行提交声明之后。

我的问题：

在我尝试运行下一个命令之前，有没有办法暂停，等待或强制查询完全完成？

当我在ISQL中运行相同的查询序列时，它可以完美地运行。有没有什么不同的ISQL，我可以强制点网Firebird提供商这样做，它不会打开这个查询或什么？

因此，为了参考，代码看起来像这样（显然这是一个非常简化的）：

    // create the table
    string commandString  = "CREATE TABLE ...";

    // run the command in a transaction and commit it
    mtransaction = Connection.BeginTransaction( IsolationLevel.Serializable );
    FbCommand command = new FbCommand(commandString, Connection, mtransaction);
    command.ExecuteNonQuery();
    transaction.Commit();
    transaction.Dispose();
    transaction = null;

    // copy the data to the new table from the old
    commandString = "INSERT INTO ...";

    mtransaction = Connection.BeginTransaction(IsolationLevel.Serializable);
    FbCommand command = new FbCommand(commandString, Connection, mtransaction);
    command.ExecuteNonQuery();
    transaction.Commit();
    transaction.Dispose();
    transaction = null;

    // drop the old table
    commandString = "DROP TABLE ...";

    mtransaction = Connection.BeginTransaction(IsolationLevel.Serializable);
    FbCommand command = new FbCommand(commandString, Connection, mtransaction);
    command.ExecuteNonQuery();

    // this command fails with the exception
    // if I pause execution in c# before running this command, and 
    // use isql to look at the db I see the new table, and the data fully populated
    // and I also see the inactive insert command in MON$STATEMENTS
    transaction.Commit();
    transaction.Dispose();
    transaction = null;

Answer 1

我遇到了同样的问题并验证了Beau的（原始）修补程序。然而，我找到了一个简单的解决方案：在事务提交后处理命令！然后不再需要重新连接。

mtransaction = Connection.BeginTransaction(IsolationLevel.Serializable);
FbCommand command = new FbCommand(commandString, Connection, mtransaction);
command.ExecuteNonQuery();
transaction.Commit();
command.Dispose(); // Thus!
transaction.Dispose();

此致航标

Answer 2

好的，问题的可怕解决方案：

我实际上能够通过关闭和处理连接，然后重新连接来实现这一点。这导致以某种方式删除“卡住”查询，然后我可以执行表drop命令。所以顺序看起来像这样：

// create the table
string commandString  = "CREATE TABLE ...";

// run the command in a transaction and commit it
mtransaction = Connection.BeginTransaction( IsolationLevel.Serializable );
FbCommand command = new FbCommand(commandString, Connection, mtransaction);
command.ExecuteNonQuery();
transaction.Commit();
transaction.Dispose();
transaction = null;

// copy the data to the new table from the old
commandString = "INSERT INTO ...";

mtransaction = Connection.BeginTransaction(IsolationLevel.Serializable);
FbCommand command = new FbCommand(commandString, Connection, mtransaction);
command.ExecuteNonQuery();
transaction.Commit();
transaction.Dispose();
transaction = null;


// ------------------  
// Drop the connection entirely and start a new one
// so the table can be dropped 

Connection.Close();
Connection.Dispose();

// build connection string 
FbConnectionStringBuilder csb = new FbConnectionStringBuilder();
csb.DataSource ... etc...

// connect
Connection = new FbConnection(connectionString);
Connection.Open();

// Now have new connection that does not have weird
// lingering query, and table can now be dropped
// -----------------



// drop the old table
commandString = "DROP TABLE ...";

mtransaction = Connection.BeginTransaction(IsolationLevel.Serializable);
FbCommand command = new FbCommand(commandString, Connection, mtransaction);
command.ExecuteNonQuery();

// this no longer fails because the connection was complete closed
// and re-opened
transaction.Commit();
transaction.Dispose();
transaction = null;

注意：我对此解决方案非常满意。它有效，但我不知道为什么。对于我来说，放弃一张桌子似乎过分和不经常。我非常赞赏任何人可能在这件事上提供的任何见解!!!

Answer 3

我相信我遇到了类似的事情。我的猜测是根本原因似乎是一个特征：MVCC。当我乱用模式，或者只删除表来重新创建时，Visual Studio通常会将其保持打开状态。我只是重启服务，一切都很好。

Firebird点网提供商没有完全执行查询？

3 个答案: