Oracle FOREIGN KEY constraint data deletion ____oracle

Today colleagues let me delete a table of data, happy to say yes;

It looks like a simple task, it can be tricky to do, originally this table is a foreign key constraint, as a primary table exists.

But I just got in touch with the system, but it's hard to die.

Then I checked the data. Confirm that the constraint name can be queried to the appropriate table to disable the constraint, which solves the

Here's how I do the experiment:

First build two tables:

CREATE TABLE T_group (ID int not null,name varchar (), primary key (ID));

CREATE TABLE T_user (ID int not null,name varchar (), GroupID int,primary key (ID), foreign key (GroupID) references P (ID));

Insert data:

INSERT into T_group values (1, ' Group1 ');
INSERT into T_group values (2, ' Group2 ');

INSERT into T_user values (1, ' qianxin ', 1);
INSERT into T_user values (2, ' Yiyu ', 2);

Attempt to delete the T_group data error. As shown in Figure I

From the table by dba_constraints query according to the constraint name

Select Constraint_name, Constraint_type, table_name from dba_constraints where Constraint_name=upper (' sys_c005376 ');

Disable constraint below

ALTER TABLE t_user disable constraint sys_c005376;

Try to delete the data again

Delete from T_group;

Delete the success "" "" "The" "" "" "" "," "" "The" "", "" ""