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Re: Against the Grain: Pascal commentary about XML and databases
- From: Ken North <ken_north@compuserve.com>
- To: Joshua Allen <joshuaa@microsoft.com>
- Date: Thu, 28 Jun 2001 22:06:57 -0700
<< RDBMS systems have evolved and gobbled up much of the research on data
warehousing to include those techniques into the engines -- witness
materialized views and bitmapped
indexes.
Someone reading this might assume the bitmapped index is a byproduct of data
warehousing, or possibly that bitmapped indexing is built on a relational
foundation.
That's not the case. The bitmapped index search pre-dates the relational
model and data warehousing. Computer Sciences' had a hierarchical DBMS in
the '60s that used bitmapped indexes. TRW's GIM DBMS at NASA MFC was updated
with bitmapped indexing in the early '70s.
Bitmapped index technology can be applied on top of a hierarchical data
model.