Apress.Expert.Oracle.Database.Architecture.9i.and.10g.Programming.Techniques.and.Solutions.Sep.2005

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CHAPTER 13 ■ PARTITIONING
ops$tkyte@ORA10G> create index partitioned_idx_global
2 on partitioned(timestamp)
3 GLOBAL
4 /
Index created.
This sets up our “warehouse” table. The data is partitioned by fiscal year and we have the
last two years’ worth of data online. This table has two indexes: one is LOCAL and the other is
GLOBAL. Now it is the end of the year and we would like to do the following:
1. Remove the oldest fiscal year data. We do not want to lose this data forever; we just
want to age it out and archive it.
2. Add the newest fiscal year data. It will take a while to load it, transform it, index it, and
so on. We would like to do this work without impacting the availability of the current
data, if at all possible.
The first step we might take would be to set up an empty table for fiscal year 2004 that
looks just like the partitioned table. We’ll use this table to exchange with the FY_2004 partition
in the partitioned table, turning that partition into a table and in turn emptying out the partition
in the partitioned table. The net effect is that the oldest data in the partitioned table will
have been, in effect, removed after the exchange:
ops$tkyte@ORA10G> create table fy_2004 ( timestamp date, id int );
Table created.
ops$tkyte@ORA10G> create index fy_2004_idx on fy_2004(id)
2 /
Index created.
We’ll do the same to the new data to be loaded. We’ll create and load a table that structurally
looks like the existing partitioned table (but that is not itself partitioned):
ops$tkyte@ORA10G> create table fy_2006 ( timestamp date, id int );
Table created.
ops$tkyte@ORA10G> insert into fy_2006
2 select to_date('31-dec-2006',’dd-mon-yyyy’)-mod(rownum,360), object_id
3 from all_objects
4 /
48521 rows created.
ops$tkyte@ORA10G> create index fy_2006_idx on fy_2006(id) nologging
2 /
Index created.
We’ll turn the current full partition into an empty partition and create a “full” table, with
the FY_2004 data in it. Also, we’ve completed all of the work necessary to have the FY_2006 data
ready to go. This would have involved verifying the data, transforming it—whatever complex
tasks we need to undertake to get it ready.