1.创建目录utl_dir用于存放导出的创建脚本
create or replace directory utl_dir as 'd:\';

2.给所有用户赋予读写utl_dir的权限
grant write,read on directory utl_dir to public;

3.创建存储过程，用来导出单个对象的创建脚本
create or replace procedure exportddl(p_type varchar2,p_name varchar2,p_filename varchar2) is
begin

  declare
    l_file           utl_file.file_type;
    l_buffer       varchar2(100);
    l_amount    binary_integer := 100;
    l_pos          integer := 1;
    l_clob         clob;
    l_clob_len  integer;
  begin

    select dbms_metadata.get_ddl(upper(p_type),p_name)||';' into l_clob from dual;
    l_clob_len := dbms_lob.getlength(l_clob);
    l_file := utl_file.fopen('UTL_DIR', p_filename||'.sql', 'a', 2000);  

    while l_pos < l_clob_len loop
      dbms_lob.read(l_clob, l_amount, l_pos, l_buffer);
      utl_file.put_line(l_file, l_buffer);
      l_pos := l_pos + l_amount;
    end loop;

    utl_file.fclose(l_file);
  end;

end exportddl;

4.创建存储过程，用来导出所有对象（表、索引、视图、同义词）的创建脚本
create or replace procedure exportddl_all(p_filename varchar2) is
begin

  for x in (select table_name from user_tables) loop
       exportddl('TABLE',x.table_name,p_filename);
  end loop;

  for x in (select index_name from user_indexes) loop
       exportddl('INDEX',x.index_name,p_filename);
  end loop;

  for x in (select view_name from user_views) loop
       exportddl('VIEW',x.view_name,p_filename);
  end loop;

  for x in (select synonym_name from user_synonyms) loop
       exportddl('SYNONYM',x.synonym_name,p_filename);
  end loop;

end exportddl_all;

5.使用过程导出scott用户所有对象的创建脚本
conn scott/tiger

exec exportddl_all('123');