ORA-00001 unique constraint  & ORA-02443 Cannot drop constraint  - nonexistent constraint

Issue 

Dropped Primary key constraint BSNL_FIBER_TIP_USED_ORDER_PK using TOAD GUI

But while inserting a row in the table even after the constraint is dropped the following error thrown

 ORA-00001: unique constraint (FMS_ADMIN.BSNL_FIBER_TIP_USED_ORDER_PK)  violated

 Solution

     1. First tried to drop the constraint using SQL Command promt.

ALTER TABLE BSNL_FIBER_TIP_USED_ORDER DROP CONSTRAINT BSNL_FIBER_TIP_USED_ORDER_PK;

 It has thrown the following error

ORA-00604: error occurred at recursive SQL level 1
ORA-06502: PL/SQL: numeric or value error
ORA-06512: at line 10
ORA-02443: Cannot drop constraint  - nonexistent constraint

2.       Checked DBA_CONSTRAINTS

 select * from dba_constraints where constraint_name='BSNL_FIBER_TIP_USED_ORDER_PK';

 No constraint available

 

3.     Then checked the DBA_INDEXES because when a primary key constraint is added to any table it automatically creates one unique index with the same name as the primary key constraint name

 SELECT * FROM DBA_INDEXES WHERE TABLE_NAME='BSNL_FIBER_TIP_USED_ORDER';

OR  directly check with index name

SELECT * FROM DBA_INDEXES 

WHERE INDEX_NAME='BSNL_FIBER_TIP_USED_ORDER_PK';

 It is observed that the unique index is available as shown below 

 

4.       Then dropped the index

 DROP INDEX BSNL_FIBER_TIP_USED_ORDER_PK;

 Index got dropped.

 

5.       Now able to insert a row.