I am trying to rename Oracle constraint name, the below code does not works. Please can you suggest a workaround or a correction.

DROP TABLE B;

DROP TABLE a;

CREATE TABLE a (a clob);

CREATE TABLE B (a number, CONSTRAINT PK_1 PRIMARY KEY(a));

DECLARE
v_handle NUMBER;
v_transform_handle NUMBER;
v_table_query CLOB;
p_source_schema varchar2(30) := 'MUDR_MIG355';
p_source_tablename varchar2(30) := 'B';
BEGIN
v_handle := DBMS_METADATA.OPEN(OBJECT_TYPE => 'TABLE');

DBMS_METADATA.SET_FILTER (v_handle, 'SCHEMA', p_source_schema);

DBMS_METADATA.SET_FILTER (v_handle, 'NAME', p_source_tablename);

v_transform_handle := DBMS_METADATA.ADD_TRANSFORM (v_handle, 'MODIFY');

DBMS_METADATA.SET_REMAP_PARAM (v_transform_handle, 'REMAP_NAME', 'PK_1', 'WOOW');

v_table_query := DBMS_METADATA.FETCH_CLOB (v_handle);

insert into a values (v_table_query);
commit;

END;
/


select * from a

SQL> create table t ( x int );

Table created.

SQL> alter table t add constraint PK primary key  ( x ) ;

Table altered.

SQL> alter table t rename constraint PK to PK1;

Table altered.