dbms_metadata.get_ddl()用于获取对象的DDL，其具体用法如下。
注意：在sqlplus里，为了更好的展示DDL，需要设置如下参数：
set line 200
set pagesize 0
set long 99999
set feedback off
set echo off
1）获得表、索引、视图、存储过程、函数的DDL
select dbms_metadata.get_ddl('TABLE','TABLE_NAME','TABLE_OWNER') from dual;
select dbms_metadata.get_ddl('INDEX','INDEX_NAME','INDEX_OWNER') from dual;
select dbms_metadata.get_ddl('VIEW','VIEW_NAME','VIEW_OWNER') from dual;
select dbms_metadata.get_ddl('PROCEDURE','PROCEDURE_NAME','PROCEDURE_OWNER') from dual;
select dbms_metadata.get_ddl('FUNCTION','FUNCTION_NAME','FUNCTION_OWNER') from dual;
下面这个脚本用于获得某个schema下所有的表、索引、视图、存储过程、函数的DDL
set pagesize 0
set long 90000
set feedback off
set echo off
spool schema_ddl.sql
SELECT DBMS_METADATA.GET_DDL('TABLE',u.table_name,u.owner) FROM DBA_TABLES u;
SELECT DBMS_METADATA.GET_DDL('VIEW',u.view_name,u.owner) FROM DBA_VIEWS u;
SELECT DBMS_METADATA.GET_DDL('INDEX',u.index_name,u.owner) FROM DBA_INDEXES u;
select dbms_metadata.get_ddl('PROCEDURE',u.object_name, u.owner,) from dba_objects u where u.object_type = 'PROCEDURE';
select dbms_metadata.get_ddl('FUNCTION',u.object_name, u.owner,) from dba_objects u where u.object_type = 'FUNCTION';
spool off;
2）获得表空间的DDL
获得单个表空间的DDL:
select dbms_metadata.get_ddl('TABLESPACE','TBS_NAME') from dual;
获得所有表空间的DDL:
SELECT DBMS_METADATA.GET_DDL('TABLESPACE', TS.tablespace_name)
FROM DBA_TABLESPACES TS;
3）获得用户的DDL
获得单个用户的DDL：
select dbms_metadata.get_ddl('USER','EPAY_USER') from dual;
获得所有用户的DDL：
SELECT DBMS_METADATA.GET_DDL('USER',U.username)
FROM DBA_USERS U;
