Author and subject indexes are available on a library database.
作者索引和学科索引可在图书馆的数据库中找到。
This query retrieves the desired author information, but it would not use either of the indexes for the join processing.
该查询检索了所需的作者信息，但是没有将索引用于连接处理。
If you know that all author IDs are Numbers, you can indicate this in your query to allow DB2 to use the DOUBLE indexes.
如果您知道所有author ID都是数字，则可以在查询中指明，从而允许DB 2使用DOUBLE索引。
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