Question

我的盒子上安装了32位驱动程序（它们是由一些DBA安装和配置的）

我写了一个简单的脚本来测试驱动程序，几乎如下

using (DataTable table = new DataTable())
{
    using (OracleConnection connection = new OracleConnection())
    {
        connection.ConnectionString = "Data Source=alias;User id=user;Password=password";
        connection.Open();
        using (OracleCommand command = connection.CreateCommand())
        {
            command.CommandType = CommandType.Text;
            command.CommandText = "SELECT * FROM DUAL";
            table.Load(command.ExecuteReader());
        }
    }
}

当我使用32位Oracle.DataAccess.dll将此应用程序编译为32位时，它会毫无障碍地执行。

但是，如果我使用Oracle.ManagedDataAccess.dll将应用程序编译为AnyCPU，则会收到ORA-12154（无法解析指定的连接标识符）错误。

如果我输入别名，它可以正常工作并告诉我连接标识符与真实数据库名称。

如果我然后更改连接字符串以使用真实数据库名称而不是别名，然后再次尝试使用托管库，它会顺利执行。

我一直在阅读并发现this回答说管理驱动程序依赖于tnsnames.ora文件来解析别名，但我依赖于sqlnet.ora和ldap.ora中定义的LDAP服务器。

当我tnsping时，它说它使用sqlnet.ora来解析名称。

那么托管驱动程序怎么不起作用？

Answer 1

这种解决方法可能适合您。您可以自己查询LDAP服务器，并将完整的连接字符串放入代码中。

您可以使用以下代码解析LDAP中的连接字符串：

  private static string ResolveServiceNameLdap(string serviceName)
  {
     string tnsAdminPath = Path.Combine(@"C:\oracle\network", "ldap.ora");
     // or something more advanced...

     // ldap.ora can contain many LDAP servers
     IEnumerable<string> directoryServers = null;

     if ( File.Exists(tnsAdminPath) ) {
        string defaultAdminContext = string.Empty;

        using ( var sr = File.OpenText(tnsAdminPath) ) {
           string line;

           while ( ( line = sr.ReadLine() ) != null ) {
              // Ignore comments or empty lines
              if ( line.StartsWith("#") || line == string.Empty )
                 continue;

              // If line starts with DEFAULT_ADMIN_CONTEXT then get its value
              if ( line.StartsWith("DEFAULT_ADMIN_CONTEXT") )
                 defaultAdminContext = line.Substring(line.IndexOf('=') + 1).Trim(new[] { '\"', ' ' });

              // If line starts with DIRECTORY_SERVERS then get its value
              if ( line.StartsWith("DIRECTORY_SERVERS") ) {
                 string[] serversPorts = line.Substring(line.IndexOf('=') + 1).Trim(new[] { '(', ')', ' ' }).Split(',');
                 directoryServers = serversPorts.SelectMany(x => {
                    // If the server includes multiple port numbers, this needs to be handled
                    string[] serverPorts = x.Split(':');
                    if ( serverPorts.Count() > 1 )
                       return serverPorts.Skip(1).Select(y => string.Format("{0}:{1}", serverPorts.First(), y));

                    return new[] { x };
                 });
              }
           }
        }

        // Iterate through each LDAP server, and try to connect
        foreach ( string directoryServer in directoryServers ) {
           // Try to connect to LDAP server with using default admin contact
           try {
              var directoryEntry = new DirectoryEntry("LDAP://" + directoryServer + "/" + defaultAdminContext, null, null, AuthenticationTypes.Anonymous);
              var directorySearcher = new DirectorySearcher(directoryEntry, "(&(objectclass=orclNetService)(cn=" + serviceName + "))", new[] { "orclnetdescstring" }, SearchScope.Subtree);
              SearchResult searchResult = directorySearcher.FindOne();
              var value = searchResult.Properties["orclnetdescstring"][0] as byte[];
              if ( value != null )
                 connectionString = Encoding.Default.GetString(value);

              // If the connection was successful, then not necessary to try other LDAP servers
              break;
           } catch {
              // If the connection to LDAP server not successful, try to connect to the next LDAP server
              continue;
           }
        }

        // If casting was not successful, or not found any TNS value, then result is an error 
        if ( string.IsNullOrEmpty(connectionString) ) 
           throw new Exception("TNS value not found in LDAP");

     } else {
        // If ldap.ora doesn't exist, then throw error 
        throw new FileNotFoundException("ldap.ora not found");
     }

     return connectionString;
  }

...

import java.io.File;

public class FileExample {

    public static void main(String[] args) throws Exception {
            File file = new File("/TEMP/../TEMP/myfile.txt");
            System.out.println("ABS: " + file.getAbsolutePath());
            System.out.println(" TO: " + file.toPath());
            System.out.println("GET: " + file.getPath());
            System.out.println("CAN: " + file.getCanonicalPath());
        }
    }


ABS: C:\TEMP\..\TEMP\myfile.txt
 TO: \TEMP\..\TEMP\myfile.txt
GET: \TEMP\..\TEMP\myfile.txt
CAN: C:\TEMP\myfile.txt

Answer 2

ODP.NET托管驱动程序依赖于在配置文件中设置的TNS_ADMIN值来查找TNSNAMES.ORA文件。如果您不想设置该值，可以将TNSNAMES.ORA文件包含在可执行文件的工作目录中，或直接在配置文件中创建TNS别名。

编辑：如果您依赖SQLNET.ORA和LDAP.ORA，您也可以将它们复制到工作目录中，或者在配置文件中设置LDAP参数。有关LDAP可用的配置文件参数，请参阅ODP.NET文档。

ODP.NET托管库确实解析别名，但32位库确实如此

2 个答案: