plsql变量对象名已存在怎么办？

SQL code

declare
    i number(4);
  v_sql varchar2(512);
begin
    select count(*) into i from user_all_tables where table_name = 'Grid_Boundary_point';
  if i > 0 then
    execute immediate 'drop table Grid_Boundary_point';
    commit;
  end if; 
  v_sql := 'create table Grid_Boundary_point(a number)';
  execute immediate v_sql;
end;

这行 execute immediate v_sql; 报错name is already used by an existing object
这是怎么回事？怎么解决？


------解决方案--------------------
当表对象存在时，对表进行删除操作时，语句改为如下：
if i>0 then
 execute immediate 'drop table Grid_Boundary_point cascade constraints';
end if;
------解决方案--------------------
if i > 0 then 改为if i >= 0 then
------解决方案--------------------
where table_name = 'Grid_Boundary_point';这后面的表名要大写才行，不然查不到数据。
------解决方案--------------------
select count(*) into i from user_all_tables where table_name = 'Grid_Boundary_point';

楼上改 Grid_Boundary_point 全为大写应该就可以了

如果还不行，将user_all_tables 改为all_tables一定就可以了