Abstract

We apply the trie structures to indexing, storing and querying structured data on secondary storage. We are interested in the storage compactness, the I/O efficiency, the order-preserving properties, the general orthogonal range queries and the exact match queries for very large files and databases. We also apply the trie structures to relational joins (set operations). We compare trie structures to various data structures on secondary storage: multipaging and grid files in the direct access method category, R-trees/R*-trees and X-trees in the logarithmic access cost category, as well as some representative join algorithms for performing join operations. Our results show that range queries by trie method are superior to these competitors in search cost when queries return more than a few records and are competitive to direct access methods for exact match queries. Furthermore, as the trie structure compresses data, it is the winner in terms of storage compared to all other methods mentioned above. We also present a new tidy function for order-preserving key-to-address transformation. Our tidy function is easy to construct and cheaper in access time and storage cost compared to its closest competitor.

Citations