Creating a Multicolumn Range-Partitioned Table By Date

Example 4-19 illustrates the column evaluation for a multicolumn range-partitioned table, storing the actual DATE information in three separate columns: year, month, and day. The partitioning granularity is a calendar quarter. The partitioned table being evaluated is created as follows:

The year value for 12-DEC-2000 satisfied the first partition, before2001, so no further evaluation is needed:

SELECT * FROM sales_demo PARTITION(before2001);

      YEAR      MONTH        DAY AMOUNT_SOLD
---------- ---------- ---------- -----------
      2000         12         12        1000

The information for 17-MAR-2001 is stored in partition q1_2001. The first partitioning key column, year, does not by itself determine the correct partition, so the second partitioning key column, month, must be evaluated.

SELECT * FROM sales_demo PARTITION(q1_2001);

      YEAR      MONTH        DAY AMOUNT_SOLD
---------- ---------- ---------- -----------
      2001          3         17        2000

Following the same determination rule as for the previous record, the second column, month, determines partition q4_2001 as correct partition for 1-NOV-2001:

SELECT * FROM sales_demo PARTITION(q4_2001);

      YEAR      MONTH        DAY AMOUNT_SOLD
---------- ---------- ---------- -----------
      2001         11          1        5000

The partition for 01-JAN-2002 is determined by evaluating only the year column, which indicates the future partition:

SELECT * FROM sales_demo PARTITION(future);

      YEAR      MONTH        DAY AMOUNT_SOLD
---------- ---------- ---------- -----------
      2002          1          1        4000

If the database encounters MAXVALUE in a partitioning key column, then all other values of subsequent columns become irrelevant. That is, a definition of partition future in the preceding example, having a bound of (MAXVALUE,0) is equivalent to a bound of (MAXVALUE,100) or a bound of (MAXVALUE,MAXVALUE).

Example 4-19 Creating a multicolumn range-partitioned table

CREATE TABLE sales_demo (
   year          NUMBER, 
   month         NUMBER,
   day           NUMBER,
   amount_sold   NUMBER) 
PARTITION BY RANGE (year,month) 
  (PARTITION before2001 VALUES LESS THAN (2001,1),
   PARTITION q1_2001    VALUES LESS THAN (2001,4),
   PARTITION q2_2001    VALUES LESS THAN (2001,7),
   PARTITION q3_2001    VALUES LESS THAN (2001,10),
   PARTITION q4_2001    VALUES LESS THAN (2002,1),

REM  12-DEC-2000
INSERT INTO sales_demo VALUES(2000,12,12, 1000);
REM  17-MAR-2001
INSERT INTO sales_demo VALUES(2001,3,17, 2000);
REM  1-NOV-2001
INSERT INTO sales_demo VALUES(2001,11,1, 5000);
REM  1-JAN-2002
INSERT INTO sales_demo VALUES(2002,1,1, 4000);