如何在c＃中知道表中哪个字段不可为空呢？

Question

如题:我要在c＃中判断下表中哪个字段不可为空好进行输入限制。不让输入空值。
还有个问题我如何判断数据库表某个字段为什么数据类型，限制长度呢？
我用的是oracle10;

Answer 1

如果一定要查，这样：
SELECT COLUMN_NAME,DATA_TYPE,DATA_LENGTH ,DATA_PRECISION, DATA_SCALE 
  FROM USER_TAB_COLUMNS 
 WHERE TABLE_NAME = 'TEST';  -- TEST改为你要查的表名

Answer 2

你可以让程序执行下面的语句自己查,然后根据结果集判断操作:
[SQL]
SQL> select TABLE_NAME, COLUMN_NAME, DATA_TYPE, DATA_LENGTH, NULLABLE from user_tab_cols where TABLE_NAME='EMP';
 
TABLE_NAME                     COLUMN_NAME                    DATA_TYPE                                                                        DATA_LENGTH NULLABLE
------------------------------ ------------------------------ -------------------------------------------------------------------------------- ----------- --------
EMP                            EMPNO                          NUMBER                                                                                    22 N
EMP                            ENAME                          VARCHAR2                                                                                  10 Y
EMP                            JOB                            VARCHAR2                                                                                   9 Y
EMP                            MGR                            NUMBER                                                                                    22 Y
EMP                            HIREDATE                       DATE                                                                                       7 Y
EMP                            SAL                            NUMBER                                                                                    22 Y
EMP                            COMM                           NUMBER                                                                                    22 Y
EMP                            DEPTNO                         NUMBER                                                                                    22 Y
 
8 rows selected
[/SQL]

Answer 3

日, 串行了, CSDN的那个插入代码的按钮总是时有时无

Answer 4

NULLABLE  = N 就不能为空