Slide 13.10: Other file operations for an indexed file Slide 13.12: File operations for secondary indexes Home

Indexing to Provide Access by Multiple Keys

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So far, our index only allows key access, i.e., you can retrieve record DG188807, but you cannot retrieve a recording of Beethoven's Symphony NO. 9.

We need to use secondary key fields consisting of album titles, composers, and artists. We relate the secondary key to a primary key which then will point to the actual byte offset.

^†A secondary key is one of several possible attributes or combinations of attributes which can be used to uniquely identify a record. Therefore, the “secondary key” here is actually not the one meant by others because the title or composer values could be duplicate.