by Burleson Consulting
The Data Warehouse Development Life Cycle
Distributed Oracle Data Warehouses
Oracle Domains And Location Transparency
Many Oracle warehouse designers recognize the need to track the
locations of remote databases while, at the same time, provide
location transparency to end users and programmers. Oracle domains
are especially important in situations of horizontal partitioning,
where tables with identical names are kept at numerous locations.
Domains establish a logical hierarchy of physical locations for an
enterprise. The sample database depicted in Figure 9.7 shows how a
domain hierarchy can be established for remote databases.
Figure 9.7 An Oracle TNS domain name hierarchy.
Each database in a distributed federation can have a synonym
assigned for all unique tables within the distributed network. In
situations where duplicate table structures exist at many locations,
abbreviated domains can be created. For example, assume that both
Japan and Ohio have a CUSTOMER table, identical in structure but
containing different rows. We could assign Oracle synonyms as
CREATE SYNONYM georgia_customer FOR
CREATE SYNONYM arizona_customer FOR
This is an excerpt from "High Performance
Data Warehousing", copyright 1997.
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