Oracle约束的属性

Oracle约束的属性

今天处理了一个由于约束插入数据失败的问题，处理时感到有些吃力，三天不练手生啊。在这里回忆一下。
Oracle数据库Constraint约束的四对属性：Deferrable/not deferrable, Deferred/immediate, enable/disable, validate/novalidate。

准备一下环境：
SQL> create table empx as select * from emp;

SQL> create table deptx as select * from dept;

SQL> alter table empx add constraint pk_empx primary key(empno);

SQL> alter table deptx add constraint pk_deptx primary key(deptno);

SQL> alter table empx add constraint fk_deptx foreign key (deptno) references deptx(deptno);

SQL> select * from deptx;

1.    DEPTNO DNAME                   LOC  
2. --------- ------------------------------------------ ---------------------------------------  
3. 10 ACCOUNTING                     NEW YORK  
4. 20 RESEARCH                   DALLAS  
5. 30 SALES                      CHICAGO  
6. 40 OPERATIONS                     BOSTON  

SQL> select * from empx;

1.      EMPNO ENAME              JOB                    MGR HIREDATE       SAL   COMM     DEPTNO  
2. ---------- ------------------------------ --------------------------- ---------- --------------- ---------- ---------- ----------  
3.       7369 SMITH              CLERK                 7902 17-DEC-80      800            20  
4.       7499 ALLEN              SALESMAN              7698 20-FEB-81         1600    300         30  
5.       7521 WARD               SALESMAN              7698 22-FEB-81         1250    500         30  
6.       7566 JONES              MANAGER               7839 02-APR-81         2975            20  
7.       7654 MARTIN             SALESMAN              7698 28-SEP-81         1250   1400         30  
8.       7698 BLAKE              MANAGER               7839 01-MAY-81         2850            30  
9.       7782 CLARK              MANAGER               7839 09-JUN-81         2450            10  
10.       7788 SCOTT              ANALYST               7566 19-APR-87         3000            20  
11.       7839 KING               PRESIDENT              17-NOV-81         5000            10  
12.       7844 TURNER             SALESMAN              7698 08-SEP-81         1500      0         30  
13.       7876 ADAMS              CLERK                 7788 23-MAY-87         1100            20  
14.       7900 JAMES              CLERK                 7698 03-DEC-81      950            30  
15.       7902 FORD               ANALYST               7566 03-DEC-81         3000            20  
16.       7934 MILLER             CLERK                 7782 23-JAN-82         1300            10  
17.   
18. 14 rows selected.