Oracle PL/SQL之ENABLE NOVALIDATE约束

SQL> create table dept as select * from scott.dept where 1=2;  
   
Table created  
   
SQL> insert into dept select * from scott.dept where deptno=10;  
   
1 row inserted  
   
SQL> insert into dept select * from scott.dept where deptno=10;  
   
1 row inserted  
   
SQL> commit;  
   
Commit complete  
   
SQL> ALTER TABLE dept ADD (UNIQUE(deptno) ENABLE NOVALIDATE);  
   
ALTER TABLE dept ADD (UNIQUE(deptno) ENABLE NOVALIDATE)  
   
ORA-02299: cannot validate (XXPO.SYS_C00830643) - duplicate keys found  
   
SQL>   

 

Google一下，发现原来在创建没有延时的UNIQUE或者PRIMARY KEY时会自动去创建一个唯一性索引。（By default a non-deferrable UNIQUE or PRIMARY KEY constraint will attempt to create a unqiue index. http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:8806498660292）

 

加上DEFERRABLE关键字，问题成功解决：

SQL> alter table company1 add constraint uq_id unique(id) DEFERRABLE ENABLE NOVALIDATE; 

Table altered
 
SQL>