1、在安裝了Oracle9i Standard Edition或者Oracle9i EntERPrise Edition的Windows機器上(IP:192.168.0.2), 產品要選了透明網關(Oracle Transparent Gateway)里訪問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_HOSTNMAE;DATABASE=pubs"
HS_DB_NAME=pubsHS_FDS_TRACE_LEVEL=OFF
HS_FDS_RECOVERY_ACCOUNT=RECOVER
HS_FDS_RECOVERY_PWD=RECOVER
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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
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$ORACLE9I_HOME\network\admin 下listener.ora內容如下：
LISTENER =
(DESCRIPTION_LIST =
(DESCRIPTION =
(ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.0.2)(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)
)
)
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重啟動這臺做gateway的Windows機器上(IP:192.168.0.2)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) )
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保存tnsnames.ora后，在命令行下：
tnsping pubs
tnsping northwind
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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）
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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;
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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';
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(假設SQL Server下pubs和northwind已有足夠權限的用戶登陸testuser,密碼為testuser_pwd)
訪問SQL Server下數據庫里的數據：
3、使用時的注意事項
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；
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ERROR 位于第 1 行：
ORA-00904: 無效列名
select "zip" from stores;
zip
-----
98056
92789
96745
98014
90019
89076
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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
)
/
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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)
)
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需要sqlserver_databaseid一致才行。
