数据迁移脚本备案
一、概述最近做的一个项目，在很大的程度上面是在做数据迁移。数据迁移往往是项目最大的风险点。在一些大的重构项目中，往往会有一个团队专门负责，可见其重要性。在项目发布中，数据迁移往往会占用很多的时间。数据迁移需要考虑很多的情况，如：迁移方案、数据备份、迁移总时间、迁移时间点、迁移后check。二、一个例子项目是想把一个登陆id:member_id换成后台交互的ali_id。为此有一个map表：cbu_member_id_mapping。我们统计了数据量大约在1亿左右。

为了实现无缝迁移，我们打算先在每个表上面添加一列，命名为：TMP_ALIID为了效率，我们打算实现并发执行。实现方式为通过把 主键mod n来实现。为了统一脚本，我们打算用动态sql来实现。为了看任务执行的进度，我们设计了一个任务表。为了记录异常情况，我们记录了异常表

1、筛选条件表  create table fin_filtrate_tbd(   tableName  varchar(64), --需订正的表名   domain varchar(64),   sql varchar2(2048)   );--添加筛选条件truncate  table fin_filtrate_tbd;insert into fin_filtrate_tbd values('fin_contract','nirvana','select p.id,p.ali_member_id_old from fin_contract p where (product_id like ''CTP%'' or product_id = ''EW\EWC'' or product_id like ''ITBU%'' or product_id like ''OTH%'') and p.ali_member_id is  null and ali_member_id_old is not null');insert into fin_filtrate_tbd values('fin_contract','zeus','select p.id,p.ali_member_id_old from fin_contract p where not (product_id like ''CTP%'' or product_id = ''EW\EWC'' or product_id like ''ITBU%'' or product_id like ''OTH%'') and p.ali_member_id is  null and ali_member_id_old is not null');2、创建错误日志表/**   select * from fin_unifyid_progress_tbd order by now desc; 查看执行过程 select * from fin_unifyid_errolog_tbd;查看报错日志**/create table fin_unifyid_errolog_tbd(   tableId varchar(64 ),   --需要订正记录ID   tableName  varchar(64 ), --需订正的表名   errcode number,   errmsg varchar2(1024 )   );--记录任务结果create table fin_unifyid_progress_tbd(   now date,   eigenvalue varchar(64),   num number   );3、存储过程create or replace procedure upgradeMemberId(tableNametemp in varchar2, --更新表名                                            domaintemp    in varchar2 --中供诚信通代号                                            --batchtemp     in number --批次                                            ) as  v_sql        varchar2(256);  v_errcode    varchar2(64);  v_errmsg     varchar2(256);  v_cursor_sql varchar2(512);  v_id         number;  v_member_id  varchar2(256);  v_ali_id     number;  TYPE type_cursor is ref cursor;  v_cursor    type_cursor;  v_amount    number := 0; -- batch commit number -- v_partition number := 3; --v_partition分区数begin  begin    select a.sql      into v_cursor_sql      from fin_filtrate_tbd a     where a.tableName = tableNametemp       and a.domain = domaintemp;      OPEN v_cursor FOR v_cursor_sql;     -- using v_partition, batchtemp;    LOOP      fetch v_cursor        into v_id, v_member_id;      exit when v_cursor%notfound;          if (domaintemp = 'nirvana') then        v_sql := ' select  NVL(sum(b.ali_id),0)  from cbu_member_id_mapping b where b.member_id=:1 AND ROWNUM = 1';        execute immediate v_sql          into v_ali_id          using v_member_id;              if v_ali_id != 0 then          v_sql := 'update ' || tableNametemp || ' set ' ||                   ' TMP_ALIID=:1,ALI_ID=:2 where id=:3';          execute immediate v_sql            using to_char(v_ali_id), v_ali_id, v_id;        end if;      else        v_sql := 'update ' || tableNametemp || ' set ' ||                 ' TMP_ALIID=:1 where id=:2';        execute immediate v_sql          using v_member_id, v_id;            end if;      v_amount := v_amount + 1;      if (mod(v_amount, 1000) = 0) then        insert into fin_unifyid_progress_tbd        values          (sysdate,           tableNametemp || '_' || domaintemp || '_' || 3,           v_amount);        commit;      end if;    end LOOP;  exception    when others then      v_errcode := sqlcode;      v_errmsg  := sqlerrm;      insert into fin_unifyid_errolog_tbd      values        (v_id, tableNametemp, v_errcode, v_errmsg);  END;  commit;  close v_cursor;  commit;end upgradeMemberId;