Check the existence of public synonyms Remove the public synonyms

在安装12c Cloud Control时遭遇Check the existence of public synonyms， Remove the public synonyms错误，由于之前安装过一次，可能没删除干净
但是不知道public synonym名称是什么，上mos上查查，终于找到了一篇文章，解决方法如下：
1.删除资料库用户：
drop user SYSMAN cascade;
drop user SYSMAN_MDS cascade;
drop user MGMT_VIEW cascade;
drop user SYSMAN_RO cascade;
drop user SYSMAN_OPSS cascade;
drop user SYSMAN_APM cascade; 
drop user SYSMAN_BIP;
drop user CLOUD_SWLIB_USER cascade;
drop user CLOUD_ENGINE_USER cascade;
drop role MGMT_USER;
2.删除同义词：
select 'drop '|| decode(owner,'PUBLIC',owner||' synonym '||synonym_name, ' synonym '||owner||'.'||synonym_name) ||';' from dba_synonyms where table_owner in ('SYSMAN', 'SYSMAN_MDS', 'MGMT_VIEW', 'SYSMAN_BIPLATFORM', 'SYSMAN_APM', 'SYSMAN_OPSS', 'SYSMAN_RO') ;
删除之后用如下语句查询一下：
SQL> select owner,synonym_name from dba_synonyms where table_owner in ('SYSMAN', 'SYSMAN_MDS','MGMT_VIEW','SYSMAN_BIP','SYSMAN_APM','SYSMAN_OPSS','SYSMAN_RO') ; 
3.删除表空间;
select 'drop tablespace '||tablespace_name||' including contents and datafiles;' from dba_tablespaces where tablespace_name like 'MGMT%';
4.删除对象：
delete from SCHEMA_VERSION_REGISTRY where COMP_NAME='Metadata Services';
delete from SCHEMA_VERSION_REGISTRY where COMP_NAME='Authorization Policy Manager';
delete from SCHEMA_VERSION_REGISTRY where COMP_NAME='Oracle Platform Security Services';
commit;

执行以上步骤之后，安装顺利完成！