当前位置：网站首页>SQL constraints

SQL constraints

2022-07-19 06:41:00 【hello,world_ yzs】

Put into production today , Because the constraints are stuck for a long time
cause :
Change the table structure , Change the fields that cannot be empty into fields that can be empty .
sql：
alter table tablename modify Field name null;
In this way, the corresponding non empty constraints should be deleted together , I don't know why not , You need to delete one by one manually .

external conditions ：
1.plsql Do not show constraints
2. Production environment sql The table results are different from the table structure of the test environment

The root cause ：
Understanding of constraints
The operation of querying and creating constraints is unclear

mysql Check constraint _MySQL Database access sql Statement to add constraints and view constraints

oracle Query constraints

oracle constraint_type problem

The leader said not to change the database structure casually
If it is not empty, it can be written to death , Then the code determines that the value is not displayed

原网站

版权声明
本文为[hello,world_ yzs]所创，转载请带上原文链接，感谢
https://yzsam.com/2022/200/202207170519368044.html

边栏推荐

猜你喜欢

随机推荐