您可以在任何数据库中进行快速测试来确认这一点，方法是打开一个视图，然后按向下箭头键。

You can do a quick test to confirm this in any database by opening a view and then pressing the down arrow.

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这个函数尝试关闭以前打开的数据库连接。

This function attempts to close the previously opened database connection.

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第一，如果数据库尚未打开的话，我们需要打开它。

First, we need to open the database if it was not previously opened.

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