最近做项目涉及到vb连接oracle数据库，而用户希望不安装oracle客户端实现。最终通过总结当前的各种技术，采用了以下方案：

    1、收集下列动态链接库DLL,可以在oracle9i和oracle10g中找到。

       oci.dll

       ocijdbc.dll

       ociw32.dll

       orannzsbbl1.dll

       oraoccil1.dll

       oraociei11.dll

       ojdbc14.jar和classes12.jar

    2、建立数据库链接文件，格式与oracle中的链接一致。

    DataSourceName=
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = oracle9i)
    )
  )

    3、vb项目中实现链接，关键代码为：

       引用：Private Declare Function SetEnvironmentVariable Lib "kernel32" Alias "SetEnvironmentVariableA" (ByVal lpName As String, ByVal lpValue As String) As Long
       调用：

       PathStr = Environ("path") 

       If Right(PathStr, 1) <> ";" Then PathStr = PathStr & ";"
       If InStr(UCase(";" & PathStr), UCase(";" & oraclePath & ";")) = 0 Then PathStr = PathStr & oraclePath & ";"
       SetEnvironmentVariable "PATH", PathStr              SetEnvironmentVariable "NLS_LANG", "SIMPLIFIED CHINESE_CHINA.ZHS16GBK"      SetEnvironmentVariable "TNS_ADMIN", oraclePath 

      conn.Open "Provider=MSDAORA.1;User ID=" + databasename + ";Password=" + password + ";Data Source=ptx;"