Alternative File Organizations

Many alternatives exist, each ideal for some situation , and not so good in others:

• Heap files: Suitable when typical access is a file scan retrieving all records.
• Sorted Files: Best if records must be retrieved in some order, or only a `range’ of records is needed.
• Hashed Files: Good for equality selections.
  • File is a collection of buckets. Bucket = primary page plus zero or more overflow pages.
  • Hashing function h: h(r) = bucket in which record r belongs. h looks at only the search fields of r.
• Clustered Files: Tuples from > 1 relation stored together to speed up joins (later….)

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