SIGMOD '85 Proceedings of the 1985 ACM SIGMOD international conference on Management of data
Storage and Querying of E-Commerce Data
Proceedings of the 27th International Conference on Very Large Data Bases
Lossy Reduction for Very High Dimensional Data
ICDE '02 Proceedings of the 18th International Conference on Data Engineering
Optimized column-oriented model: a storage and search efficient representation of medical data
ITBAM'10 Proceedings of the First international conference on Information technology in bio- and medical informatics
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Storage and querying of high dimensional sparsely populated data creates new challenge to conventional horizontal model. It requires supporting large number of columns and frequently altering of database schema. The sparsity of data degrades performance in both time and space. A 3-ary vertical representation [5] can be used. But the cardinality of the vertical table grows exponentially when the density of the non-null values increases. It is also difficult to support multiple data types usinga single vertical table. In this paper, we have presented a compressed 1-ary vertical representation where schema evolution is easy and size grows linearly with non-null density. Queries can be processed on compressed form of data without decompression. Decompression is done only when the result is necessary. We have considered three alternative representations: 3-ary uncompressed vertical, 1-ary compressed bit-array and 1-ary compressed offset. Experimental results show the superiority of 1-ary offset representation in both space and time.