The ability to mock out a database table in-memory is a huge time saver, especially when you consider how long it takes to start up an actual database.
在内存中模拟数据库表可以节省大量时间，尤其是在启动实际数据库需要很长时间时。
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Usually media failure is caused by either the complete loss of a data file or a system change number (SCN) time stamp being out of sync with the rest of the database.
In this case, mocking out the database interaction allows you to focus on the Grails functionality, doing it in a fraction of the time it would otherwise take.