How to delete the primary key from without using constraint name

Question

CREATE TABLE Persons (
    ID int PRIMARY KEY,
    LastName varchar(255) NOT NULL,
    FirstName varchar(255),
    Age int
);

How to remove the primary key as there is no constraint defined?

Answer 1

"How to remove PK as there is no constraint defined?"

Actually it's every bit as simple as you might hope:

SQL> create table t23 (id number primary key);

Table created.

SQL> select constraint_name, constraint_type
  2  from user_constraints
  3  where table_name = 'T23'
  4  /

CONSTRAINT_NAME                C
------------------------------ -
SYS_C0034419                   P

SQL> alter table t23 drop primary key;

Table altered.

SQL> select constraint_name, constraint_type
  2  from user_constraints
  3  where table_name = 'T23'
  4  /

no rows selected

SQL>