通過異構服務設置訪問多個SQL數據庫
2024-07-21 02:33:45
供稿：網友
假設我們要在Oracle里同時能訪問SQL Server里默認的pubs和Northwind兩個數據庫。
可參考最初寫的通過異構服務鏈接oracle 和sql server 數據庫服務器
1、在安裝了ORACLE9i Standard Edition或者ORACLE9i EnterPRise Edition的windows機器上(ip:192.168.0.1),
產品要選了透明網關(Oracle Transparent Gateway)里要訪問Microsoft SQL Server數據庫.
$ORACLE9I_HOME/tg4msql/admin下新寫initpubs.ora和initnorthwind.ora配置文件
initpubs.ora內容如下:
HS_FDS_CONNECT_INFO="SERVER=sqlserver_hostname;DATABASE=pubs"
HS_DB_NAME=pubs
HS_FDS_TRACE_LEVEL=OFF
HS_FDS_RECOVERY_ACCOUNT=RECOVER
HS_FDS_RECOVERY_PWD=RECOVER
initnorthwind.ora內容如下:
HS_FDS_CONNECT_INFO="SERVER=sqlserver_hostname;DATABASE=Northwind"
HS_DB_NAME=Northwind
HS_FDS_TRACE_LEVEL=OFF
HS_FDS_RECOVERY_ACCOUNT=RECOVER
HS_FDS_RECOVERY_PWD=RECOVER
(藍色字的部分可以根據具體要訪問的SQL Server數據庫的情況而修改)
$ORACLE9I_HOME/network/admin 下listener.ora內容如下:
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.1)(PORT = 1521))
)
)
)
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(GLOBAL_DBNAME = test9)
(ORACLE_HOME = d:/oracle/ora92)
(SID_NAME = test9)
)
(SID_DESC=
(SID_NAME=pubs)
(ORACLE_HOME=d:/Oracle/Ora92)
(PROGRAM=tg4msql)
)
(SID_DESC=
(SID_NAME=northwind)
(ORACLE_HOME=d:/Oracle/Ora92)
(PROGRAM=tg4msql)
)
)
重啟動這臺做gateway的windows機器上(IP:192.168.0.1)TNSListener服務.
(凡是按此步驟新增可訪問的SQL Server數據庫時，TNSListener服務都要重啟動)
2、ORACLE8I，ORACLE9I的服務器端配置tnsnames.ora, 添加下面的內容:
pubs =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)(PORT = 1521))
)
(CONNECT_DATA =
(SID = pubs)
)
(HS = pubs)
)
northwind =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)(PORT = 1521))
)
(CONNECT_DATA =
(SID = northwind)
)
(HS = northwind)
)
保存tnsnames.ora后,在命令行下
tnsping pubs
tnsping northwind
出現類似提示，即為成功
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)
(PORT = 1521))) (CONNECT_DATA = (SID = pubs)) (HS = pubs))
OK（20毫秒）
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)
(PORT = 1521))) (CONNECT_DATA = (SID = northwind)) (HS = northwind))
OK（20毫秒）
設置數據庫參數global_names=false。
設置global_names=false不要求建立的數據庫鏈接和目的數據庫的全局名稱一致。
global_names=true則要求, 多少有些不方便。
oracle9i和oracle8i都可以在DBA用戶下用SQL命令改變global_names參數
alter system set global_names=false;
建立公有的數據庫鏈接:
create public database link pubs connect to testuser identified by testuser_pwd using 'pubs';
create public database link northwind connect to testuser identified by testuser_pwd using 'northwind';
(假設SQL Server下pubs和northwind已有足夠權限的用戶登錄testuser,密碼為testuser_pwd)
訪問SQL Server下數據庫里的數據:
select * from stores@pubs;
...... ......
select * from region@northwind;
...... ......
使用sql *plus copy命令從本地數據庫復制暑假到MS SQL SERVER中：
copy from scott/tiger@myoracle insert EMP@pubs using select * from EMP
3、使用時的注重事項
ORACLE通過訪問SQL Server的數據庫鏈接時，用select * 的時候字段名是用雙引號引起來的。
例如：
create table stores as select * from stores@pubs;
select zip from stores；
ERROR 位于第 1 行:
ORA-00904: 無效列名
select "zip" from stores;
zip
-----
98056
92789
96745
98014
90019
89076
已選擇6行。
用SQL Navigator或Toad看從SQL Server轉移到ORACLE里的表的建表語句為:
CREATE TABLE stores
("stor_id" CHAR(4) NOT NULL,
"stor_name" VARCHAR2(40),
"stor_address" VARCHAR2(40),
"city" VARCHAR2(20),
"state" CHAR(2),
"zip" CHAR(5))
PCTFREE 10
PCTUSED 40
INITRANS 1
MAXTRANS 255
TABLESPACE users
STORAGE (
INITIAL 131072
NEXT 131072
PCTINCREASE 0
MINEXTENTS 1
MAXEXTENTS 2147483645
)
/
總結:
WINDOWS下ORACLE9i網關服務器在$ORACLE9I_HOME/tg4msql/admin目錄下的initsqlserver_databaseid.ora
WINDOWS下ORACLE9i網關服務器listener.ora里面
(SID_DESC=
(SID_NAME=sqlserver_databaseid)
(ORACLE_HOME=d:/Oracle/Ora92)
(PROGRAM=tg4msql)
)
UNIX或WINDOWS下ORACLE8I,ORACLE9I服務器tnsnames.ora里面
northwind =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)(PORT = 1521))
)
(CONNECT_DATA =
(SID = sqlserver_databaseid)
)
(HS = sqlserver_databaseid)
)
sqlserver_databaseid一致才行.
