对于同义词的备份我们有多种方式来实现，如直接通过脚本生成同义词的创建脚本，或者使用dbms_metadata.get_ddl来提取同义词的定义脚本。然而在使用传统的exp或是datapump expdp实现schema级别数据迁移时，不能导出公共同义词。尽管如此，我们依旧可以使用导出导入的方式来实现。所不同的是，我们使用FULL=Y的方式来单独导出同义词，然后再将其导入的目标数据库。下文是对此进行的描述，末尾也给出了手动创建同义词的脚本。
1、环境
--源数据库
SQL> select * from v$version where rownum<2;
BANNER
----------------------------------------------------------------
Oracle Database 10g Release 10.2.0.3.0 - 64bit Production
SQL> show parameter db_nam
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_name string XM6320
SQL> select count(*) from dba_synonyms where table_owner='GOEX_ADMIN';
COUNT(*)
----------
1042
--目标数据库
--目标数据库schema goex_admin的所有数据均来源于源数据库，但是使用datapump导入后，无同义词
SQL> select * from v$version where rownum<2;
BANNER
----------------------------------------------------------------
Oracle Database 10g Release 10.2.0.3.0 - 64bit Production
SQL> show parameter db_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_name string KM3625
--下面的查询中仅有两个同义词，这两个同义是在创建DB的时候手动创建的，非使用datapump导入产生的
SQL> select count(*) from dba_synonyms where table_owner='GOEX_ADMIN';
COUNT(*)
----------
22、从源数据库导出公共同义词
oracle@BKDB01p:~> env | grep SID
ORACLE_SID=XM6320
#使用下面的方式导出公共同义词，对于可导出的对象我们可以查询数据字典 DATABASE_EXPORT_OBJECTS
oracle@BKDB01p:~> expdp goex_admin/xxx directory=db_dump_dir dumpfile=syns.dmp logfile=exp_syns.log full=y \
> include=PUBLIC_SYNONYM/SYNONYM:\"IN \(SELECT synonym_name FROM dba_synonyms WHERE table_owner=\'GOEX_ADMIN\'\)\"
Export: Release 10.2.0.3.0 - 64bit Production on Wednesday, 19 June, 2013 16:11:19
Copyright (c) 2003, 2005, Oracle. All rights reserved.
Connected to: Oracle Database 10g Release 10.2.0.3.0 - 64bit Production
Starting "GOEX_ADMIN"."SYS_EXPORT_FULL_01": goex_admin/******** directory=db_dump_dir dumpfile=syns.dmp logfile=exp_syns.log
full=y include=PUBLIC_SYNONYM/SYNONYM:"IN (SELECT synonym_name FROM dba_synonyms WHERE table_owner='GOEX_ADMIN')"
Estimate in progress using BLOCKS method...
Processing object type DATABASE_EXPORT/SCHEMA/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 0 KB
Processing object type DATABASE_EXPORT/SCHEMA/PUBLIC_SYNONYM/SYNONYM
Master table "GOEX_ADMIN"."SYS_EXPORT_FULL_01" successfully loaded/unloaded
******************************************************************************
Dump file set for GOEX_ADMIN.SYS_EXPORT_FULL_01 is:
/u02/database/XM6320/BNR/dump/syns.dmp
Job "GOEX_ADMIN"."SYS_EXPORT_FULL_01" successfully completed at 16:11:233、导入公共同义词到目标数据库
oracle@BKDB01p:~> cp /u02/database/XM6320/BNR/dump/syns.dmp /u02/database/KM3625/BNR/dump/
oracle@BKDB01p:~> export ORACLE_SID=KM3625
oracle@BKDB01p:~> impdp goex_admin/xxx directory=db_dump_dir dumpfile=syns.dmp logfile=imp_syns.log full=y include=synonym
Import: Release 10.2.0.3.0 - 64bit Production on Wednesday, 19 June, 2013 16:15:52
Copyright (c) 2003, 2005, Oracle. All rights reserved.
Connected to: Oracle Database 10g Release 10.2.0.3.0 - 64bit Production
Master table "GOEX_ADMIN"."SYS_IMPORT_FULL_01" successfully loaded/unloaded
Starting "GOEX_ADMIN"."SYS_IMPORT_FULL_01": goex_admin/******** directory=db_dump_dir dumpfile=syns.dmp logfile=imp_syns.log full=y include=synonym
Processing object type DATABASE_EXPORT/SCHEMA/PUBLIC_SYNONYM/SYNONYM
ORA-31684: Object type SYNONYM:"PUBLIC"."GO_GA_SYS_DATAPUMP_PARA_TBL" already exists
ORA-31684: Object type SYNONYM:"PUBLIC"."BO_SYS_DATAPUMP_PKG" already exists
Job "GOEX_ADMIN"."SYS_IMPORT_FULL_01" completed with 2 error(s) at 16:16:12
#上面的导入过程可以看到，Processing object type DATABASE_EXPORT/SCHEMA/PUBLIC_SYNONYM/SYNONYM实现了同义词的导入
#同时由于有两个同义词存在，也给出了提示
#验证导入的同义词
oracle@BKDB01p:~> sqlplus / as sysdba
SQL*Plus: Release 10.2.0.3.0 - Production on Wed Jun 19 16:16:24 2013
Copyright (c) 1982, 2006, Oracle. All Rights Reserved.
Connected to:
Oracle Database 10g Release 10.2.0.3.0 - 64bit Production
SQL> show parameter db_name
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_name string KM3625
SQL> select count(*) from dba_synonyms where table_owner='GOEX_ADMIN';
COUNT(*)
----------
10424、手动创建同义词的脚本
ACCEPT input_owner PROMPT 'Enter the owner of table:'
SET HEADING OFF VERIFY OFF FEEDBACK OFF TERMOUT OFF;
SPOOL $LOG/create_synonym.sql
--Author: Robinson
--Blog : http://blog.csdn.net/robinson_0612
SELECT 'create public synonym ' || synonym_name || ' for ' || table_owner || '.' || table_name || ';'
FROM dba_synonyms s
WHERE s.owner = 'PUBLIC' AND s.table_owner = UPPER ('&input_owner');
SET HEADING ON VERIFY ON TERMOUT ON FEEDBACK OFF;
SPOOL OFF;
--@$LOG/create_synonym.sql;