当我尝试向system-period temporal table添加FOREIGN KEY ... ON DELETE CASCADE约束时遇到错误-在我的示例中STATE表下方。
我可以让应用程序层进行清理，但是我更希望让数据库来处理自己的内部事务。
父表：
0001.00 -- *************************************************************************************************
0002.00 -- Create the table.
0003.00 -- *************************************************************************************************
0004.00 CREATE OR REPLACE TABLE country (
0005.00 iso2 CHAR(2) NOT NULL,
0006.00 iso3 CHAR(3) NOT NULL,
0007.00 isonum CHAR(3) NOT NULL,
0008.00 name VARCHAR(45) NOT NULL,
0009.00 sys_start
0010.00 TIMESTAMP(12) NOT NULL GENERATED ALWAYS AS ROW BEGIN IMPLICITLY HIDDEN,
0011.00 sys_end
0012.00 TIMESTAMP(12) NOT NULL GENERATED ALWAYS AS ROW END IMPLICITLY HIDDEN,
0013.00 sys_ts
0014.00 TIMESTAMP(12) NOT NULL GENERATED ALWAYS AS TRANSACTION START ID
0015.00 IMPLICITLY HIDDEN,
0016.00 PERIOD SYSTEM_TIME(sys_start, sys_end),
0017.00 PRIMARY KEY(iso2)
0018.00 ) RCDFMT rcountry;
0019.00
0020.00 COMMIT;
0021.00
0022.00 -- *************************************************************************************************
0023.00 -- Create a history table to track all changes.
0024.00 -- *************************************************************************************************
0025.00 CREATE OR REPLACE TABLE countryh LIKE country;
0026.00
0027.00 COMMIT;
0028.00
0029.00 -- *************************************************************************************************
0030.00 -- Associate our history table with the main table and tell the system to add a row to the history
0031.00 -- table when a row is deleted so we'll have a record of the deletion.
0032.00 -- *************************************************************************************************
0033.00 ALTER TABLE country ADD VERSIONING USE HISTORY TABLE countryh
0034.00 ON DELETE ADD EXTRA ROW;
0035.00
0036.00 COMMIT;
子表：
0001.00 -- *************************************************************************************************
0002.00 -- Create the table.
0003.00 -- ****************************************************************************|********************
0004.00 CREATE OR REPLACE TABLE state (
0005.00 id BIGINT GENERATED ALWAYS AS IDENTITY (START WITH 1 CYCLE),
0006.00 cntry_id CHAR(2) NOT NULL,
0007.00 code VARCHAR(3) NOT NULL,
0008.00 name VARCHAR(35) NOT NULL,
0009.00 sys_start
0010.00 TIMESTAMP(12) NOT NULL GENERATED ALWAYS AS ROW BEGIN IMPLICITLY HIDDEN,
0011.00 sys_end
0012.00 TIMESTAMP(12) NOT NULL GENERATED ALWAYS AS ROW END IMPLICITLY HIDDEN,
0013.00 sys_ts
0014.00 TIMESTAMP(12) NOT NULL GENERATED ALWAYS AS TRANSACTION START ID
0015.00 IMPLICITLY HIDDEN,
0016.00 PERIOD SYSTEM_TIME(sys_start, sys_end),
0017.00 PRIMARY KEY(id),
0018.00 UNIQUE (cntry_id, code)
0019.00 ) RCDFMT rstate;
0020.00
0021.00 COMMIT;
0022.00
0023.00 -- *************************************************************************************************
0024.00 -- Create a history table to track all changes.
0025.00 -- *************************************************************************************************
0026.00 CREATE OR REPLACE TABLE stateh LIKE state;
0027.00
0028.00 COMMIT;
0029.00
0030.00 -- *************************************************************************************************
0031.00 -- Associate our history table with the main table and tell the system to add a row to the history
0032.00 -- table when a row is deleted so we'll have a record of the deletion.
0033.00 -- *************************************************************************************************
0034.00 ALTER TABLE state ADD VERSIONING USE HISTORY TABLE stateh
0035.00 ON DELETE ADD EXTRA ROW;
0036.00
0037.00 COMMIT;
0038.00
0039.00 ALTER TABLE state ADD FOREIGN KEY(cntry_id) REFERENCES country(iso2)
0040.00 ON DELETE CASCADE;
0041.00
0042.00 COMMIT;
我的编译列表中显示的error是：
MSG ID SEV RECORD TEXT
SQ20525 30 39 Position 1 Operation on table STATE in HILLB1 not
allowed.
我的工作日志中显示的错误是：
Constraint is not valid.
当我执行F1提示以获取更多信息时，我得到：
Message . . . . : Constraint is not valid.
Cause . . . . . : Constraint *N cannot be added for file STATE in library
HILLB1 for TYPE value *N. For a referential constraint (TYPE *REFCST), the
parent file *N in library *N has a delete rule of *N and update rule of *N.
The constraint was not added because of errors. The reason code is 6. The
reason codes and their meanings are as follows:
06 - The file is a system-period temporal table and the referential
constraint cannot use the delete rule of *CASCADE, *SETDFT, and *SETNULL.
很明显Db2 for i不喜欢我要尝试做的事情。
我还尝试将FOREIGN KEY定义放入CREATE OR REPLACE TABLE语句中，并得到相同的错误（尽管在第34行）。
当父表删除行时，真的没有办法使从属表（即系统周期的时态表）删除相关行吗？