Oracle drop if exists

场景
删除表，视图等对象时，静默执行，不返回报错信息
类似dorp table if exists，语句可反复执行
开发人员编写sql，让实施人员执行
直接写drop table abc，如果abc表已经被删除或者不存在，返回报错信息，对于不懂sql的实施人员来说，会产生干扰

代码示例
创建存储过程
适用于drop table, procedure, function, trigger, view, sequence

create or replace procedure dropObject(ObjName varchar2,ObjType varchar2)
is
 v_counter number := 0;   
begin    
  if upper(ObjType) = 'TABLE' then
    select count(*) into v_counter from user_tables where table_name = upper(ObjName);
    if v_counter > 0 then          
      execute immediate 'drop table ' || ObjName || ' cascade constraints';        
    end if;   
  end if;
  if upper(ObjType) = 'PROCEDURE' then
    select count(*) into v_counter from User_Objects where object_type = 'PROCEDURE' and OBJECT_NAME = upper(ObjName);
      if v_counter > 0 then          
        execute immediate 'DROP PROCEDURE ' || ObjName;        
      end if; 
  end if;
  if upper(ObjType) = 'FUNCTION' then
    select count(*) into v_counter from User_Objects where object_type = 'FUNCTION' and OBJECT_NAME = upper(ObjName);
      if v_counter > 0 then          
        execute immediate 'DROP FUNCTION ' || ObjName;        
      end if; 
  end if;
  if upper(ObjType) = 'TRIGGER' then
    select count(*) into v_counter from User_Triggers where TRIGGER_NAME = upper(ObjName);
      if v_counter > 0 then          
        execute immediate 'DROP TRIGGER ' || ObjName;
      end if; 
  end if;
  if upper(ObjType) = 'VIEW' then
    select count(*) into v_counter from User_Views where VIEW_NAME = upper(ObjName);
      if v_counter > 0 then          
        execute immediate 'DROP VIEW ' || ObjName;        
      end if; 
  end if;
  if upper(ObjType) = 'SEQUENCE' then
    select count(*) into v_counter from user_sequences where sequence_name = upper(ObjName);
      if v_counter > 0 then          
        execute immediate 'DROP SEQUENCE ' || ObjName;        
      end if; 
  end if;
end;

使用存储过程
创建temp_table表之前，判断，if exists then drop

此语句示例在pl/sql developer中执行
”/”必须在行首，之前不能有空格
begin
  dropObject('temp_table','table');
end;
/
create table