An access path is defined with key fields specified in a given order and/or with dynamic or static selection maintenance specified. Together the keys and selection maintenance specify which records on a file are implemented as a logical file. However, the operating system implements logical files by automatically creating what is called an active index. The active index is part of the operating system's implementation of logical files. There is a separate active index for each set of key and static selection maintenance.
Where possible, the operating system tries to share an active index between logical files. If logical files have the same key fields and static selection maintenance, they may share an active index. If two similar logical files (same keys) have dynamic select/omit maintenance, they may be able to share the same active index. However, if one (or both) has different static select/omit maintenance, they cannot share an active index, and the operating system always creates separate active indexes.
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