Check whether the table in the Oracle database has a primary key

Check whether the table in the oralce database has a primary key (primary key)

declare pkCount number;   --表中主键数量
begin
  for v_ref in (select t.TABLE_NAME from user_tables t) loop
            select count(1) into pkCount from user_constraints c where c.TABLE_NAME = v_ref.TABLE_NAME;
            if pkCount  = 0 then
                   dbms_output.put_line(v_ref.TABLE_NAME);--打印没有设置主键的表名称
            end if;
  end loop;
 
exception
  when others then
    dbms_output.put_line(SQLCODE || ' ' || SQLERRM);
end;