如何在Oracle中的间隔分区表中存储NULL值? [英] How to store NULL values in an interval partitioned table in Oracle?

问题描述

我们使用分区来删除旧数据(Oracle将其称为

We use partitioning to be able to delete old data (Oracle calls this ILM). There is a column with the "best before date", after which the partition will be dropped.

为避免必须手动(或按脚本)添加分区，我们使用间隔分区:

To avoid having to add partitions manually (or per script), we use interval partitioning:

CREATE TABLE my_table (
  id NUMBER NOT NULL PRIMARY KEY,
  --... other columns ...
  t DATE
) PARTITION BY RANGE (t) INTERVAL(NUMTODSINTERVAL(7, 'DAY')) (
  PARTITION PRE2018 VALUES LESS THAN (DATE '2018-01-01')
);

INSERT INTO my_table(id, t) VALUES (1, SYSDATE);
-- 1 row inserted.

...效果很好，但是我们不能将分区日期保留为NULL:

... which works fine, but we cannot leave the partitioning date to NULL:

INSERT INTO my_table(id, t) VALUES (2, NULL);
-- ORA-14300: partitioning key maps to a partition outside maximum permitted number of partitions

如何解决?

推荐答案

例如，您可以这样做:

CREATE TABLE my_table (
    ID NUMBER NOT NULL PRIMARY KEY,
    --... other columns ...
    t TIMESTAMP(0),
    PARTITION_KEY TIMESTAMP(0) GENERATED ALWAYS AS (COALESCE(t, TIMESTAMP '2999-01-01 00:00:00')) VIRTUAL
)
PARTITION BY RANGE (PARTITION_KEY) INTERVAL( NUMTODSINTERVAL(7, 'DAY')) ( 
    PARTITION PRE2018 VALUES LESS THAN (TIMESTAMP '2018-01-01 00:00:00')
);

像PARTITION FOR (TIMESTAMP '2999-01-01 00:00:00')

也许您还可以使用GENERATED ALWAYS AS (COALESCE(t, TIMESTAMP '1900-01-01 00:00:00'))，这取决于哪种逻辑更适合您.

Perhaps you can also use GENERATED ALWAYS AS (COALESCE(t, TIMESTAMP '1900-01-01 00:00:00')) depending what fits better to your logic.

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