database SQL 错误：ORA-02298：无法验证 (SYSTEM.AEROPUERTO_FK) - 未找到父键
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SQL Error: ORA-02298: cannot validate (SYSTEM.AEROPUERTO_FK) - parent keys not found
提问by andandandand
I'm getting the following error in on Oracle SQL Developer:
我在 Oracle SQL Developer 中收到以下错误：
Error starting at line 1 in command:
ALTER TABLE AEROPUERTO ADD CONSTRAINT AEROPUERTO_FK FOREIGN KEY (CODIGO_CIUDAD) REFERENCES CIUDAD(CODIGO)
Error report:
SQL Error: ORA-02298: cannot validate (SYSTEM.AEROPUERTO_FK) - parent keys not found
02298. 00000 - "cannot validate (%s.%s) - parent keys not found"
*Cause: an alter table validating constraint failed because the table has
child records.
*Action: Obvious
Why?
为什么？
回答by rsenna
There are records in AEROPUERTOthat point to records that do not exist in CIUDAD.
有记录在AEROPUERTO那个点到不存在的记录CIUDAD。
To find out which records of AEROPUERTOhave that kind of issue:
要找出哪些记录AEROPUERTO有这种问题：
select * from AEROPUERTO where CODIGO_CIUDAD not in (select CODIGO from CIUDAD)
If the result set is not empty, you dohave orphanaged records. You'll need to add the missing CIUDADrecords in order to create the AEROPUERTO_FKforeign key, orupdate all the erroneous AEROPUERTO.CODIGO_CIUDADto null (if this is a nullable field, but you will lose the city information for those airport records).
如果结果集不为空，则您确实有孤立记录。您需要添加缺失的CIUDAD记录以创建AEROPUERTO_FK外键，或将所有错误更新AEROPUERTO.CODIGO_CIUDAD为空（如果这是一个可为空的字段，但您将丢失这些机场记录的城市信息）。
回答by Amit Kumar
remove primary key constraint from the column in which you want to add the foreign key
从要添加外键的列中删除主键约束
