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Oracle 8 Tips
by Burleson Consulting |
The Data Warehouse Development Life Cycle
Distributed Oracle Data Warehouses
USING SNAPSHOTS TO PROPAGATE SUBSETS OF MASTER TABLES
As you have seen, snapshot replication is very handy for taking a
master and copying it to a remote location. But, what if we only
want to replicate a portion of the tables? Fortunately, Oracle
provides a method for excluding certain rows and columns from
replicated tables. For example, let’s assume we are replicating a
central employee table for use by our New York branch. However, we
only want to replicate employee records for those who work at the
New York branch, and we want to exclude confidential columns, such
as the employee’s salary. The snapshot would appear as follows:
CREATE SNAPSHOT emp_ny
REFRESH FAST
START WITH SYSDATE
NEXT NEXT_DAY(trunc(sysdate),’TUESDAY’)+6/24
AS
SELECT
emp_nbr,
emp_name,
emp_phone,
emp_hire_date
FROM emp@hq WHERE department = ‘NY’;
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