oracle迁移postgres之-Ora2Pg

2021-07-24 00:12:42

描述

Ora2Pg:甲骨文PostgreSQL数据库模式转换器是一个免费的工具用于Oracle数据库迁移到PostgreSQL兼容模式。它连接Oracle数据库,扫描它自动提取其结构或数据,然后生成SQL脚本,您可以加载到PostgreSQL数据库。
Ora2Pg从Oracle数据库逆向工程可以使用巨大的企业数据库迁移或者复制一些Oracle数据成一个PostgreSQL数据库。它很容易使用,不需要任何Oracle数据库知识比提供所需的参数连接Oracle数据库。

安装

首先要感谢Gilles Darold提供了Ora2Pg工具。目前最新的版本1.74
1. 安装依赖包
yum install perl-DBI perl-DBD-Pg perl-ExtUtils-MakeMaker gcc
wget http://search.cpan.org/CPAN/authors/id/P/PY/PYTHIAN/DBD-Oracle-1.74.tar.gz
tar -zxvf DBD-Oracle-1.74.tar.gz
cd DBD-Oracle-1.74
source /home/oracle/.bash_profile
perl Makefile.PL -l
make
make install

2.安装 ora2pg包
下载地址：https://github.com/darold/ora2pg/tree/v17.4
unzip ora2pg-17.4.zip
cd ora2pg-17.4
perl Makefile.PL
make
make install
/usr/local/bin/ora2pg -v --默认安装在/usr/local/bin/目录下；版本为v17.4。
Ora2Pg v17.4

配置

Ora2Pg配置文件默认位置：/etc/ora2pg/ora2pg.conf； 这个在安装Ora2Pg会有提示。
/usr/local/bin/ora2pg -c /etc/ora2pg/ora2pg.conf
下面针对配置做下简单讲解
1. Limiting object to export。
#允许或者（排除）某个对象或者某些对象导出；
/etc/ora2pg/ora2pg.conf
ORACLE_HOME /u01/app/oracle
#This directive is used to set the data source name in the form standard DBI DSN
ORACLE_DSN dbi:Oracle:ora229
ORACLE_USER lottu
ORACLE_PWD li0924
LOGFILE /tmp/Ora2Pg.log
SCHEMA LOTTU
TYPE TABLE INSERT
ALLOW ORATAB
OUTPUT lottu01.sql

[root@sdserver40_222 ~]# ora2pg -c /etc/ora2pg/ora2pg.conf
[========================>] 1/1 tables (100.0%) end of scanning.
[> ] 0/1 tables (0.0%) end of scanning.
[========================>] 1/1 tables (100.0%) end of table export.
[====> ] 1/6 rows (16.7%) Table ORATAB (1 recs/sec)
[========================>] 6/6 rows (100.0%) on total estimated data (1 sec., avg: 6 recs/sec)
[root@sdserver40_222 ~]# cat lottu01.sql
-- Generated by Ora2Pg, the Oracle database Schema converter, version 17.4
-- Copyright 2000-2016 Gilles DAROLD. All rights reserved.
-- DATASOURCE: dbi:Oracle:ora229

SET client_encoding TO 'UTF8';

\set ON_ERROR_STOP ON


CREATE TABLE oratab (
id bigint,
name varchar(20)
) ;

-- Generated by Ora2Pg, the Oracle database Schema converter, version 17.4
-- Copyright 2000-2016 Gilles DAROLD. All rights reserved.
-- DATASOURCE: dbi:Oracle:ora229

SET client_encoding TO 'UTF8';

\set ON_ERROR_STOP ON

BEGIN;
INSERT INTO oratab (id,name) VALUES (1001,E'li0924');

ALTER SEQUENCE IF EXISTS ggs_marker_seq RESTART WITH 7117;
ALTER SEQUENCE IF EXISTS ggs_ddl_seq RESTART WITH 7117;
COMMIT
解释：
#参数 ALLOW：指导出匹配的对象；例如：ALLOW EMPLOYEES SALE_.* COUNTRIES .*_GEOM_SEQ ：导出的对象名称有 EMPLOYEES, COUNTRIES, 以 'SALE_'开头 以 '_GEOM_SEQ'结尾的。
#参数 EXCLUDE就是排除匹配的对象；与ALLOW相反。
#参数 WHERE：对象记录排除；这个只针对TYPE TABLE.
#上例还可以这样执行；配置文件注释ALLOW/EXCLUDE；在执行命令用-a : allow|-e : exclude来替代。
#执行命令 ora2pg -a "ORATAB" -c /etc/ora2pg/ora2pg.conf

2.Export Oracle tables as foreign table for oracle_fdw
#做oracle迁移到postgres;其中oracle_fdw也是一个很好的方案. 那上例只需改下参数TYPE FDW;并把参数WHERE注释；这对oracle_fdw是一大助力。避免手写外部表脚本。

[root@sdserver40_222 ~]# ora2pg -c /etc/ora2pg/ora2pg.conf
[========================>] 1/1 tables (100.0%) end of scanning.
[========================>] 1/1 tables (100.0%) end of table export.
[root@sdserver40_222 ~]# cat lottu02.sql
-- Generated by Ora2Pg, the Oracle database Schema converter, version 17.4
-- Copyright 2000-2016 Gilles DAROLD. All rights reserved.
-- DATASOURCE: dbi:Oracle:ora229

SET client_encoding TO 'UTF8';

\set ON_ERROR_STOP ON

CREATE FOREIGN TABLE oratab (
id bigint,
name varchar(20)
) SERVER orcl OPTIONS(schema 'LOTTU', table 'ORATAB');

3. Modifying object structure
#由上面导出的oratab.id类型是bigint；可是我只需要int就行；不需要字段类型为长整型；name类型由varchar(20)改为text类型。
#同时导出表的名字我也想修改为：lottu
[root@sdserver40_222 ~]# cat /etc/ora2pg/ora2pg.conf
ORACLE_HOME /u01/app/oracle
#This directive is used to set the data source name in the form standard DBI DSN
ORACLE_DSN dbi:Oracle:ora229
ORACLE_USER lottu
ORACLE_PWD li0924
LOGFILE /tmp/Ora2Pg.log
SCHEMA LOTTU
TYPE TABLE
ALLOW ORATAB
REPLACE_TABLES ORATAB:LOTTU01
MODIFY_TYPE ORATAB:ID:INT,ORATAB:NAME:TEXT
OUTPUT lottu03.sql
[root@sdserver40_222 ~]# ora2pg -c /etc/ora2pg/ora2pg.conf
[========================>] 1/1 tables (100.0%) end of scanning.
[========================>] 1/1 tables (100.0%) end of table export.
[root@sdserver40_222 ~]# cat lottu03.sql
-- Generated by Ora2Pg, the Oracle database Schema converter, version 17.4
-- Copyright 2000-2016 Gilles DAROLD. All rights reserved.
-- DATASOURCE: dbi:Oracle:ora229

SET client_encoding TO 'UTF8';

\set ON_ERROR_STOP ON

CREATE TABLE lottu01 (
id int,
name text
) ;
解释：
#参数：REPLACE_TABLES 替换表名；格式REPLACE_TABLES ORIG_TBNAME1:DEST_TBNAME1 ORIG_TBNAME2:DEST_TBNAME2；这个很好理解
#参数：MODIFY_TYPE 指定表中字段类型。

4.Extract procedures/functions/packages
[root@sdserver40_222 ~]# ora2pg -c /etc/ora2pg/ora2pg.conf
[========================>] 2/2 functions (100.0%) end of output.
[root@sdserver40_222 ~]# cat lottu04.sql
-- Generated by Ora2Pg, the Oracle database Schema converter, version 17.4
-- Copyright 2000-2016 Gilles DAROLD. All rights reserved.
-- DATASOURCE: dbi:Oracle:ora229

SET client_encoding TO 'UTF8';

\set ON_ERROR_STOP ON

CREATE OR REPLACE FUNCTION ora2pg_16_to10 (v_16_data text) RETURNS bigint AS $body$
DECLARE

v_data bigint;
v_char varchar(18);

BEGIN
v_char:=substring(v_16_data from 2);
select sum(data) into v_data from
(
SELECT (
case substr(upper(v_char),rownum,1)
when 'A' then '10'
when 'B' then '11'
when 'C' then '12'
when 'D' then '13'
when 'E' then '14'
when 'F' then '15'
else substring(v_char from rownum for 1) end
)*power(16,length(v_char)-rownum) data
connect by rownum<=length(v_char)
);
return v_data;
exception
when others then
return null;
end;
$body$
LANGUAGE PLPGSQL
SECURITY DEFINER
;
-- REVOKE ALL ON FUNCTION ora2pg_16_to10 (v_16_data text) FROM PUBLIC;

CREATE OR REPLACE FUNCTION ora2pg_add_1 (v_in_1 bigint,v_in_2 bigint) RETURNS bigint AS $body$
DECLARE

v_data bigint;

BEGIN
v_data := v_in_1+v_in_2;
return v_data;
exception
when others then
return null;
end;
$body$
LANGUAGE PLPGSQL
SECURITY DEFINER
;
-- REVOKE ALL ON FUNCTION ora2pg_add_1 (v_in_1 bigint,v_in_2 bigint) FROM PUBLIC;

[root@sdserver40_222 ~]# cat /etc/ora2pg/ora2pg.conf
ORACLE_HOME /u01/app/oracle
#This directive is used to set the data source name in the form standard DBI DSN
ORACLE_DSN dbi:Oracle:ora229
ORACLE_USER lottu
ORACLE_PWD li0924
LOGFILE /tmp/Ora2Pg.log
SCHEMA LOTTU
TYPE FUNCTION
ALLOW ORA2PG_.*
OUTPUT lottu04.sql

备注：
上面提供了两个函数；ora2pg_16_to10函数有postgres不支持的语法；ora2pg_add_1函数是简单的函数。意思是说ora2pg支持简单的函数导出；
其中connect by语法是postgres不支持的语法；导出并不会做修改；这样的代码在postgres执行之前需要修改。这个修改代码需要各位的开发技能。
未完待续.....
若更了解Ora2Pg；可以去看官方文档。

【FAQ】
[root@sdserver40_222 ~]# ora2pg -c /etc/ora2pg/ora2pg.conf
install_driver(Oracle) failed: Can't load '/usr/local/lib64/perl5/auto/DBD/Oracle/Oracle.so' for module DBD::Oracle: libclntsh.so.11.1: cannot open shared object file: No such file or directory at /usr/lib64/perl5/DynaLoader.pm line 200.
at (eval 13) line 3
Compilation failed in require at (eval 13) line 3.
Perhaps a required shared library or dll isn't installed where expected
at /usr/local/share/perl5/Ora2Pg.pm line 1323
[root@sdserver40_222 ~]# source /home/oracle/.bash_profile
[root@sdserver40_222 ~]# echo $ORACLE_HOME/lib >> /etc/ld.so.conf

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