文档课题：测试oracle主键被激活后，依赖该列的外建需手动重新激活.
环境：oracle 19.12
以下为测试过程.
SQL> desc emp3;                                              
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 EMPLOYEE_ID                                        NUMBER(6)
 FIRST_NAME                                         VARCHAR2(20)
 LAST_NAME                                 NOT NULL VARCHAR2(25)
 EMAIL                                     NOT NULL VARCHAR2(25)
 PHONE_NUMBER                                       VARCHAR2(20)
 HIREDATE                                  NOT NULL DATE
 JOB_ID                                    NOT NULL VARCHAR2(10)
 SALARY                                             NUMBER(8,2)
 COMMISSION_PCT                                     NUMBER(2,2)
 MANAGER_ID                                         NUMBER(6)
 DEPARTMENT_ID                                      NUMBER(4)

SQL> select constraint_name,constraint_type,status from user_constraints where table_name='EMP3';

CONSTRAINT_NAME                C STATUS
------------------------------ - --------
SYS_C007954                    C ENABLED
SYS_C007955                    C ENABLED
SYS_C007956                    C ENABLED
SYS_C007957                    C ENABLED

SQL> alter table emp3 add constraint PK_EMP_ID primary key (employee_id);

Table altered.

SQL> alter table emp3
  2    add constraint fk_emp_mgr
  3        foreign key (manager_id)
  4        references emp3(employee_id);

Table altered.

SQL> select constraint_name,constraint_type,status from user_constraints where table_name='EMP3';
CONSTRAINT_NAME      C STATUS
-------------------- - --------
FK_EMP_MGR         R ENABLED
SYS_C007954          C ENABLED
SYS_C007955          C ENABLED
SYS_C007956          C ENABLED
SYS_C007957          C ENABLED
PK_EMP_ID           P ENABLED

6 rows selected.

SQL> alter table emp3 disable constraint pk_emp_id;
alter table emp3 disable constraint pk_emp_id
*
ERROR at line 1:
ORA-02297: cannot disable constraint (ORA1.PK_EMP_ID) - dependencies exist

SQL> alter table emp3 disable constraint FK_EMP_MGR; 

Table altered.

SQL> select constraint_name,constraint_type,status from user_constraints where table_name='EMP3';
CONSTRAINT_NAME      C STATUS
-------------------- - --------
SYS_C007954          C ENABLED
SYS_C007955          C ENABLED
SYS_C007956          C ENABLED
SYS_C007957          C ENABLED
PK_EMP_ID           P ENABLED
FK_EMP_MGR         R DISABLED

6 rows selected.

SQL> alter table emp3 disable primary key cascade;

Table altered.

SQL> select constraint_name,constraint_type,status from user_constraints where table_name='EMP3';

CONSTRAINT_NAME      C STATUS
-------------------- - --------
SYS_C007954          C ENABLED
SYS_C007955          C ENABLED
SYS_C007956          C ENABLED
SYS_C007957          C ENABLED
FK_EMP_MGR         R DISABLED
PK_EMP_ID           P DISABLED

6 rows selected.

SQL> alter table emp3 enable constraint FK_EMP_MGR;
alter table emp3 enable constraint FK_EMP_MGR
*
ERROR at line 1:
ORA-02270: no matching unique or primary key for this column-list

SQL> alter table emp3 enable primary key;

Table altered.

SQL> select constraint_name,constraint_type,status from user_constraints where table_name='EMP3';

CONSTRAINT_NAME      C STATUS
-------------------- - --------
SYS_C007954          C ENABLED
SYS_C007955          C ENABLED
SYS_C007956          C ENABLED
SYS_C007957          C ENABLED
PK_EMP_ID           P ENABLED
FK_EMP_MGR         R DISABLED

6 rows selected.

SQL> select constraint_name,constraint_type,status from user_constraints where table_name='EMP3'

CONSTRAINT_NAME                C STATUS
------------------------------ - --------
SYS_C007954                    C ENABLED
SYS_C007955                    C ENABLED
SYS_C007956                    C ENABLED
SYS_C007957                    C ENABLED
PK_EMP_ID                     P ENABLED
FK_EMP_MGR                   R DISABLED

6 rows selected.
注意：主键被激活后，依赖该列的外建依然是disabled.
SQL> alter table emp3 enable constraint fk_emp_mgr;

Table altered.

SQL> select constraint_name,constraint_type,status from user_constraints where table_name='EMP3';

CONSTRAINT_NAME                C STATUS
------------------------------ - --------
FK_EMP_MGR                   R ENABLED
SYS_C007954                    C ENABLED
SYS_C007955                    C ENABLED
SYS_C007956                    C ENABLED
SYS_C007957                    C ENABLED
PK_EMP_ID                     P ENABLED

6 rows selected.

结论：主键被激活后，依赖该列的外建需手动重新激活.