Contiguous record storage   Oracle Tips by Burleson Consulting

High Performance Data Warehousing

Introduction of the Relational Model

* Contiguous record storage--While this was not an initial feature of the relational model, the ability of a relational database to store rows in physical sequential order on disk makes it very appealing for data warehouse applications. As you may know, most data warehouse queries retrieve many rows in a predefined order, and a relational database can aid in reducing physical I/O, because many rows are placed into the database buffer in a single physical I/O.

Figure 1.9 An example of referential integrity.

One of the greatest benefits of relational databases for data warehouses is the concept of data independence. Because data relationships are not hard-linked with pointers, systems developers are able to quickly design warehouses based solely on business requirements.
As mentioned earlier, Codd's relations, or tables, consist of columns and rows. Dr. Codd chose to call a row a tuple (rhymes with couple), and he refers to many rows as instantiations of tuples. Personally, I believe that this obtuse terminology helped to ensure that the relational model gained respect as a legitimate offering, and many professionals began to use Dr. Codd's confusing terminology.

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This is an excerpt from "High Performance Data Warehousing", copyright 1997.

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