Can we rename the system generated constraint_name as per our convenience ?

Question

I created a table by
CREATE TABLE table_name AS (SELECT * FROM existing_table_name WHERE 1=2);
and got the all constraints of the existing table with default names. I want to rename those constraints as per current table data.
thank you in advance
Edited by: 930934 on Apr 29, 2012 8:51 AM

Answer 1

sb92075 wrote:
WHY? What difference does the CONSTRAINT_NAME make?A lot. Because with a consistent naming convention it's a lot easier to understand the error message when the constraint is violated.
When you see this error message:
SQL> insert into foo (id, some_value) values (1, -1);
insert into foo (id, some_value) values (1, -1)
ERROR at line 1:
ORA-02290: check constraint (FOOBAR.SYS_C0016210) violatedDo you really know which column violates the constraint?
Now give the constraint a meaningful name, like this:
SQL> insert into foo (id, some_value) values (1,-1);
insert into foo (id, some_value) values (1,-1)
ERROR at line 1:
ORA-02290: check constraint (FOOBAR.CHK_SOME_VALUE_POSITIVE) violatedthen it becomes obvious which of the colums is meant.
Or think about foreign keys:
SQL> insert into bar (id, foo_id, product_id) values (1, 0, 0);
insert into bar (id, foo_id, product_id) values (1, 0, 0)
ERROR at line 1:
ORA-02291: integrity constraint (FOOBAR.SYS_C0016214) violated - parent key not foundAgain, with the right name, it becomes obvious which column violated the constraint:
SQL> insert into bar (id, foo_id, product_id) values (1, 0, 0);
insert into bar (id, foo_id, product_id) values (1, 0, 0)
ERROR at line 1:
ORA-02291: integrity constraint (FOOBAR.FK_BAR_REFERENCES_FOO) violated - parent key not foundMost probably one would use a slighlty less verbose name for the foreign key in real life due to Oracles limit on identifiers, but it shows how much more readable an error message is, with a proper name.