概述
本文演示如何执行一个 SQL Server 分布式查询来从 FoxPro dbc 和 dbf 文件获取数据
更多信息
Microsoft SQL Server 提供了执行基于 OLE DB providers 的查询的能力 这是靠使用
OpenQuery 或 OpenRowset TransactSQL 函数或使用包含一个已连接服务器名四部查询来执行的
例如:
sp_addlinkedserver mylinkedserver product_name myoledbprovider data_source
location provider_string catalog
SELECT * FROM OPENQUERY(mylinkedserver select * from table)
可以用 Microsoft OLE DB provider for ODBC (MSDASQL) 和 Visual FoxPro ODBC driver 来
设置一个已连接服务器 (linked server) 来执行基于 FoxPro dbc 和 dbf 文件的分布式查询 不支持用 Jet OLEDB Provider 和 FoxPro
以下 TSQL 示例代码演示如何用 OpenQuery 和 OpenRowset 函数设置和使用分布式查询 FoxPro
它也演示了如何从 SQL Server 更新一个远程 FoxPro 表 你可以在一个 SQL Server 机器上安装了 Visual FoxPro ODBC driver 后 在 SQL Query Analyzer 中测试这些代码 你需要改变数据源名和路径到适当的 FoxPro 文件:
/* OPENROWSET 和 OPENQUERY 示例 以 VFP 通过 ODBC OLE DB provider */
/* 这些 OPENROWSET 示例依赖于示例文件 VFP\data\Testdatadbc
如果你的数据在不同的位置请修改你的代码 */
====================================================
使用 DBC 文件 读和更新
====================================================
OPENROWSET DSNless 示例
select * from openrowset(MSDASQL
Driver=Microsoft Visual FoxPro Driver;
SourceDB=e:\VFP\data\Testdatadbc;
SourceType=DBC
select * from customer where country != USA order by country)
go
select * from openrowset(MSDASQL
Driver=Microsoft Visual FoxPro Driver;
SourceDB=e:\VFP\data\Testdatadbc;
SourceType=DBC
select * from customer where region=WA)
go
Update openrowset(MSDASQL
Driver=Microsoft Visual FoxPro Driver;
SourceDB=e:\VFP\data\Testdatadbc;
SourceType=DBC
select * from customer where region=WA)
set region = Seattle
go
check to verify which rows were updated
select * from openrowset(MSDASQL
Driver=Microsoft Visual FoxPro Driver;
SourceDB=e:\VFP\data\Testdatadbc;
SourceType=DBC
select * from customer where region=Seattle)
go
OPENROWSET DSN 示例
/* 注意如果 SQL Server 是配置为使用本地帐号 DSN 示例可能失败*/
select * from openrowset(MSDASQL
DSN=Visual FoxPro Database;
SourceDB=e:\VFP\data\Testdatadbc;
SourceType=DBC
select * from customer where country != USA order by country)
go
/* sp_addlinkedserver 示例 */
sp_addlinkedserver example with DSN
/* 你需要生成一个 DSN 并使它指向 Testdata 数据库
修改你的代码以反映 DBC 位置 */
/* 注意如果 SQL Server 是配置为使用本地帐号 DSN 示例可能失败*/
sp_addlinkedserver VFP Testdata Database With DSN
MSDASQL
VFP System DSN
go
sp_addlinkedsrvlogin VFP Testdata Database With DSN FALSE NULL NULL NULL
go
SELECT *
FROM OPENQUERY([VFP Testdata Database With DSN] select * from customer
where region = Seattle )
go
Update using OpenQuery
Update OPENQUERY([VFP Testdata Database With DSN] select * from customer
where region=WA)
set region = Seattle
go
/* SP_addlinkedserver example with DSNless connection */
/* This example also depends on the sample files Testdatadbc
Modify your code accordingly for differences in location or DBC name */
sp_addlinkedserver VFP Testdata Database With No DSN
MSDASQL
NULL
NULL
Driver={Microsoft Visual FoxPro Driver};UID=;PWD=;SourceDB=e:\VFP\dataTestdatadbc;SourceType=DBC;Exclusive=No;BackgroundFetch=Yes;Collate=Machine;
go
sp_addlinkedsrvlogin VFP Testdata Database With No DSN FALSE NULL NULL NULL
go
SELECT *
FROM OPENQUERY([VFP Testdata Database With No DSN] select * from customer
where country != USA order by country)
go
====================================================
使用 VFP driver read and update data from VFP sample dbf files
====================================================
OPENROWSET DSNless example
select * from openrowset(MSDASQL
Driver=Microsoft Visual FoxPro Driver;
SourceDB=e:\VFP\data;
SourceType=DBF
select * from customer where country != USA order by country)
go
perform UPDATE
Update openrowset(MSDASQL
Driver=Microsoft Visual FoxPro Driver;
SourceDB=e:\VFP\data;
SourceType=DBF
select * from customer where region=Seattle)
set region = WA
go
verify update
select * from openrowset(MSDASQL
Driver=Microsoft Visual FoxPro Driver;
SourceDB=e:\VFP\data;
SourceType=DBF
select * from customer where region = WA)
go
OPENROWSET DSN example
DSN points to the folder where dbf files are
/* Note this Example may fail if SQL Server is configured to use a local account*/
select * from openrowset(MSDASQL
DSN=Visual FoxPro Tables;
SourceDB=e:\VFP\data;
SourceType=DBF
select * from customer where country != USA order by country)
go
