Oracle Database 11 g - Online Public Access Catalog

CHAPTER 12 ■ DATA WAREHOUSING 547Let’s create our first baseline interval partition and see how Oracle maintains partitions forus. Here’s a table called EBDA_ALERT_NOTIFICATIONS that houses all the database alerts for theDBAs:CREATE TABLE edba_alert_notifications(alert_notification_id number,subject varchar2(2000),hostname varchar2(55),database_name varchar2(55),severity varchar2(1),alert_log_id number,message varchar2(4000),creation_date date default sysdate,created_by varchar2(55),modification_date date default sysdate,modified_by varchar2(55))partition by range (creation_date)interval (numtoyminterval(1,'MONTH'))( PARTITION p_jan2007 VALUESLESS THAN (TO_DATE('01-JAN-2007','DD-MON-RRRR')))/Table created.You can see that CREATION_DATE is the partitioning key for this table using the numtoymintervalfunction based on the month. Let’s query USER_TAB_PARTITIONS to verify that this table wascreated accordingly. The following query example shows that high_value for the partition is2007-01-01 00:00:00:SQL> col partition_name for a20SQL> col high_value for a50 word_wrappedSQL> select partition_name, high_value2 from user_tab_partitions3 where table_name='EDBA_ALERT_NOTIFICATIONS'4* order by partition_position5 /PARTITION_NAME HIGH_VALUE---------------- -------------------------------------P_JAN2007TO_DATE(' 2007-01-01 00:00:00', 'SYYYY-MM-DDHH24:MI:SS', 'NLS_CALENDAR=GREGORIAN')Now, let’s insert 12 rows to simulate 12 months of rolling partitions. These rows are fabricated,but the key point is that the CREATION_DATE column has the first day of each month forthe year 2007.