具有时间有效性的 Oracle table 的主键违规

Question

能否请您分享一些关于 Table 上具有 Oracle 时间有效性的主键操作的信息？

我创建了一个具有以下架构的 table

Create table TemporalTable_1 (
    Customer_ID number(8),
    Customer_name varchar2(100),
    valid_period_start timestamp, 
    valid_period_end timestamp, 
    period for valid_period(valid_period_start, valid_period_end),
    constraint TemporalTable_1_PK primary key (Customer_ID , VALID_PERIOD)
)

我有来自另一个 table“其他Table”的记录，我需要复制到 TemporalTable_1

 
Customer_ID       | Customer_name        | Valid_period_start      | Valid_Period_end
------------------+----------------------+-------------------------+-----------------------
00001             | John Chan            | 01 JUN 2020 00:00:00    | 09 JUN 2020 23:59:59
00001             | Johnny Chan          | 10 JUN 2020 00:00:00    | Null

以下是我的脚本：

insert into TemporalTable_1 select * from OtherTable;

ORA-00001: 违反唯一约束 (TemporalTable_1)

执行插入语句前，table为空白。所以我的问题是为什么不允许我将行复制到 TemporalTable_1 即使行有不同的 valid_period.

难道是因为Oracle其实并不关心主键上的有效期列？

提前致谢！

Answer 1

非常确定时间有效性还没有配备以本地处理主键等。

SQL> Create table TemporalTable_1 (
  2      Customer_ID number(8),
  3      Customer_name varchar2(100),
  4      valid_period_start timestamp,
  5      valid_period_end timestamp,
  6      period for valid_period(valid_period_start, valid_period_end),
  7      constraint TemporalTable_1_PK primary key (Customer_ID , VALID_PERIOD)
  8  );

Table created.

SQL> select column_name, hidden_column
  2  from   user_tab_cols
  3  where  table_name = 'TEMPORALTABLE_1'
  4  order by column_id;

COLUMN_NAME                    HID
------------------------------ ---
CUSTOMER_ID                    NO
CUSTOMER_NAME                  NO
VALID_PERIOD_START             NO
VALID_PERIOD_END               NO
VALID_PERIOD                   YES

VALID_PERIOD 列是隐藏的，这意味着我们使用它来协助我们实现该功能所需的查询转换，而不是添加主键。

Answer 2

期间名称（VALID_PERIOD 在您的情况下）列仅包含您的期间 ID。检查此脚本及其输出：

--drop table TemporalTable purge;
-- formatting for sqlplus:
col periodname for a20;
col constraint_name for a20;
col search_condition_vc for a80;
col valid_period_start for a16;
col valid_period_end   for a16;
col PERIODSTART for a20;
col PERIODEND   for a20;
alter session set nls_timestamp_format='yyyy-mm-dd hh24:mi';
-- end of formatting

Create table TemporalTable (
    Customer_ID number(8),
    Customer_name varchar2(10)
);

alter table TemporalTable add (
    valid_period_start timestamp, 
    valid_period_end   timestamp,
    period for valid_period(valid_period_start, valid_period_end)
);

ALTER TABLE TemporalTable ADD (
    vt_start DATE,
    vt_end DATE,
    PERIOD FOR vt (vt_start, vt_end)
);
-- inserting overlapping records:
insert into TemporalTable
select 1, 'A' , date'2020-01-01', date'2020-01-10', date'2020-01-01', date'2020-01-10' from dual union all
select 1, 'B' , date'2020-01-05', date'2020-01-08', date'2020-01-01', date'2020-01-10' from dual
/
commit;
-- check valid_period and vt hidden columns:
select tt.*,valid_period,vt from TemporalTable tt
/
select * 
from TemporalTable 
       AS OF PERIOD FOR valid_period DATE '2020-01-06'
/
select 
 constraint_name,
 constraint_type,
 search_condition_vc
from user_constraints c 
where table_name='TEMPORALTABLE';

select * from sys.SYS_FBA_PERIOD 
where obj#=(select object_id from user_objects where object_name='TEMPORALTABLE');

如您所见，我添加了 2 个有效期：VALID_PERIOD 与您的情况和 VT 一样。请注意，隐藏列 VALID_PERIOD 和 VT 仅包含它们的 ID。 table 中的所有行都相同。此外，在 the following presentation by Philipp Salvisberg 中，您可以看到 Oracle 中的时间有效性尚不支持时间完整性约束，而且它甚至不支持检查重叠时间段。所以你还不能创建这样的约束。但是你可以阅读这些东西的旧方法（例如，像外键约束 START_DATE -> prev(END_DATE) 和 ID 上的唯一约束，START_DATE)

输出：

CUSTOMER_ID CUSTOMER_N VALID_PERIOD_STA VALID_PERIOD_END VT_START            VT_END              VALID_PERIOD         VT
----------- ---------- ---------------- ---------------- ------------------- ------------------- ------------ ----------
          1 A          2020-01-01 00:00 2020-01-10 00:00 2020-01-01 00:00:00 2020-01-10 00:00:00    726847999  726848005
          1 B          2020-01-05 00:00 2020-01-08 00:00 2020-01-01 00:00:00 2020-01-10 00:00:00    726847999  726848005



CUSTOMER_ID CUSTOMER_N VALID_PERIOD_STA VALID_PERIOD_END VT_START            VT_END
----------- ---------- ---------------- ---------------- ------------------- -------------------
          1 A          2020-01-01 00:00 2020-01-10 00:00 2020-01-01 00:00:00 2020-01-10 00:00:00
          1 B          2020-01-05 00:00 2020-01-08 00:00 2020-01-01 00:00:00 2020-01-10 00:00:00



CONSTRAINT_NAME      C SEARCH_CONDITION_VC
-------------------- - --------------------------------------------------------------------------------
VALID_PERIOD52D1FF   C (VALID_PERIOD_START < VALID_PERIOD_END) and (VALID_PERIOD > 0)
VT52D205             C (VT_START < VT_END) and (VT > 0)



      OBJ# PERIODNAME                FLAGS PERIODSTART          PERIODEND                 SPARE
---------- -------------------- ---------- -------------------- -------------------- ----------
     89220 VALID_PERIOD                  0 VALID_PERIOD_START   VALID_PERIOD_END
     89220 VT                            0 VT_START             VT_END

https://www.doag.org/formes/pubfiles/5217205/2013-DEV-Philipp_Salvisberg-Multi-temporal_Database_Features_in_Oracle_12c-Praesentation.pdf

具有时间有效性的 Oracle table 的主键违规

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