文档课题：主键失效对该主键对应列上索引的影响.
数据库：oracle 19.12
以下测试过程.
SQL> ALTER TABLE LOCATIONS01 DISABLE PRIMARY KEY CASCADE;

Table altered.

SQL> SELECT INDEX_NAME,INDEX_TYPE,TABLE_NAME FROM USER_INDEXES WHERE TABLE_NAME='LOCATIONS01';

no rows selected
说明：可以看到主键失效后，主键上对应的索引无法查询到.
SQL> SELECT CONSTRAINT_NAME,CONSTRAINT_TYPE,TABLE_NAME,INDEX_NAME,STATUS FROM USER_CONSTRAINTS WHERE TABLE_NAME='LOCATIONS01';

CONSTRAINT_NAME           C TABLE_NAME           INDEX_NAME      STATUS
------------------------- - -------------------- --------------- --------
SYS_C008319               C LOCATIONS01                          ENABLED
SYS_C008320               P LOCATIONS01                          DISABLED

SQL> ALTER TABLE LOCATIONS01 ENABLE PRIMARY KEY;

Table altered.

SQL> SELECT CONSTRAINT_NAME,CONSTRAINT_TYPE,TABLE_NAME,INDEX_NAME,STATUS FROM USER_CONSTRAINTS WHERE TABLE_NAME='LOCATIONS01';

CONSTRAINT_NAME           C TABLE_NAME           INDEX_NAME      STATUS
------------------------- - -------------------- --------------- --------
SYS_C008319               C LOCATIONS01                          ENABLED
SYS_C008320               P LOCATIONS01          SYS_C008320     ENABLED

SQL> SELECT INDEX_NAME,INDEX_TYPE,TABLE_NAME FROM USER_INDEXES WHERE TABLE_NAME='LOCATIONS01';

INDEX_NAME      INDEX_TYPE                  TABLE_NAME
--------------- --------------------------- --------------------
SYS_C008320     NORMAL                      LOCATIONS01

结论：oracle主键失效后对应的索引会被删除，当重新激活该主键时，索引会自动创建.