具有时间有效性的 Oracle 表的主键违规

Question

Could you please share me some light regarding to primary key operation on Table with Temporal Validity in Oracle?

I have created an table with following schema

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)
)

I have following records from another table "OtherTable" and I need to copy into the 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

Following is my script:

insert into TemporalTable_1 select * from OtherTable;

ORA-00001: unique constraint (TemporalTable_1) violated

Before execute the insert statement, the table was blank. So my question is why I am not allowed copy the row into the TemporalTable_1 even the rows have different valid_period.

Is it because Oracle actually didn't care about the valid period column on the primary key?

Thanks in advance!

Answer 1

Pretty sure that temporal validity is not yet equipped to natively handle primary keys and the like.

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 

The VALID_PERIOD column is hidden, which means we're using it to assist with our implementation of the query transformation needed for the feature, not to add primary keys on.

Answer 2

Period name(VALID_PERIOD in your case) columns contains just ID of your period. Check this script and its' output:

 --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');

As you can see I added 2 validity periods: VALID_PERIOD as in your case and VT. Notice that hidden columns VALID_PERIOD and VT contains just their ID. They are the same for all rows in the table. Moreover in the following presentation by Philipp Salvisberg you can see that Temporal Validity in Oracle doesn't support yet temporal integrity constraints yet and moreover it doesn't even support checks for overlapping periods. So you can't create such constraints yet. But you can read old methods for such things (for example, like foreign key constraints START_DATE -> prev(END_DATE) and unique contraint on ID, START_DATE)

Output:

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