这里有很多答案，但这里有一个工作示例的代码，你可以立即复制、粘贴和测试:

对我来说，在指定正确的SERVICE_NAME后，错误12514得到了解决。 您可以在服务器上的文件tnsnames中找到它。ora自带3个预定义的服务名称(其中一个是“XE”)。

I installed the Oracle Express database OracleXE112 which already comes with some preinstalled demo tables. When you start the installer you are asked for a password. I entered "xxx" as password. (not used in production) My server runs on the machine 192.168.1.158 On the server you must explicitely allow access for the process TNSLSNR.exe in the Windows Firewall. This process listens on port 1521. OPTION A: For C# (.NET2 or .NET4) you can download ODAC11, from which you have to add Oracle.DataAccess.dll to your project. Additionally this DLL depends on: OraOps11w.dll, oci.dll, oraociei11.dll (130MB!), msvcr80.dll. These DLLs must be in the same directory as the EXE or you must specify the DLL path in: HKEY_LOCAL_MACHINE\SOFTWARE\Oracle\ODP.NET\4.112.4.0\DllPath. On 64 bit machines write additionally to HKLM\SOFTWARE\Wow6432Node\Oracle\... OPTION B: If you have downloaded ODAC12 you need Oracle.DataAccess.dll, OraOps12w.dll, oci.dll, oraociei12.dll (160MB!), oraons.dll, msvcr100.dll. The Registry path is HKEY_LOCAL_MACHINE\SOFTWARE\Oracle\ODP.NET\4.121.2.0\DllPath OPTION C: If you don't want huge DLL's of more than 100 MB you should download ODP.NET_Managed12.x.x.x.xxxxx.zip in which you find Oracle.ManagedDataAccess.dll which is only 4 MB and is a pure managed DLL which works in 32 bit and 64 bit processes as well and depends on no other DLL and does not require any registry entries. The following C# code works for me without any configuration on the server side (just the default installation):

using Oracle.DataAccess.Client;
or
using Oracle.ManagedDataAccess.Client;

....

string oradb = "Data Source=(DESCRIPTION="
    + "(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.1.158)(PORT=1521)))"
    + "(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=XE)));"
    + "User Id=SYSTEM;Password=xxx;";

using (OracleConnection conn = new OracleConnection(oradb)) 
{
    conn.Open();
    using (OracleCommand cmd = new OracleCommand())
    {
        cmd.Connection  = conn;
        cmd.CommandText = "select TABLESPACE_NAME from DBA_DATA_FILES";

        using (OracleDataReader dr = cmd.ExecuteReader())
        {
            while (dr.Read())
            {
                listBox.Items.Add(dr["TABLESPACE_NAME"]);
            }
        }
    }
}

如果SERVICE_NAME=XE错误，则会得到错误12514。SERVICE_NAME是可选的。你也可以把它放在一边。

这里有很多答案，但这里有一个工作示例的代码，你可以立即复制、粘贴和测试:

对我来说，在指定正确的SERVICE_NAME后，错误12514得到了解决。 您可以在服务器上的文件tnsnames中找到它。ora自带3个预定义的服务名称(其中一个是“XE”)。

I installed the Oracle Express database OracleXE112 which already comes with some preinstalled demo tables. When you start the installer you are asked for a password. I entered "xxx" as password. (not used in production) My server runs on the machine 192.168.1.158 On the server you must explicitely allow access for the process TNSLSNR.exe in the Windows Firewall. This process listens on port 1521. OPTION A: For C# (.NET2 or .NET4) you can download ODAC11, from which you have to add Oracle.DataAccess.dll to your project. Additionally this DLL depends on: OraOps11w.dll, oci.dll, oraociei11.dll (130MB!), msvcr80.dll. These DLLs must be in the same directory as the EXE or you must specify the DLL path in: HKEY_LOCAL_MACHINE\SOFTWARE\Oracle\ODP.NET\4.112.4.0\DllPath. On 64 bit machines write additionally to HKLM\SOFTWARE\Wow6432Node\Oracle\... OPTION B: If you have downloaded ODAC12 you need Oracle.DataAccess.dll, OraOps12w.dll, oci.dll, oraociei12.dll (160MB!), oraons.dll, msvcr100.dll. The Registry path is HKEY_LOCAL_MACHINE\SOFTWARE\Oracle\ODP.NET\4.121.2.0\DllPath OPTION C: If you don't want huge DLL's of more than 100 MB you should download ODP.NET_Managed12.x.x.x.xxxxx.zip in which you find Oracle.ManagedDataAccess.dll which is only 4 MB and is a pure managed DLL which works in 32 bit and 64 bit processes as well and depends on no other DLL and does not require any registry entries. The following C# code works for me without any configuration on the server side (just the default installation):

using Oracle.DataAccess.Client;
or
using Oracle.ManagedDataAccess.Client;

....

string oradb = "Data Source=(DESCRIPTION="
    + "(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=192.168.1.158)(PORT=1521)))"
    + "(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=XE)));"
    + "User Id=SYSTEM;Password=xxx;";

using (OracleConnection conn = new OracleConnection(oradb)) 
{
    conn.Open();
    using (OracleCommand cmd = new OracleCommand())
    {
        cmd.Connection  = conn;
        cmd.CommandText = "select TABLESPACE_NAME from DBA_DATA_FILES";

        using (OracleDataReader dr = cmd.ExecuteReader())
        {
            while (dr.Read())
            {
                listBox.Items.Add(dr["TABLESPACE_NAME"]);
            }
        }
    }
}

如果SERVICE_NAME=XE错误，则会得到错误12514。SERVICE_NAME是可选的。你也可以把它放在一边。

我有这个问题，修复是确保在tnsnames。ora SERVICE_NAME是数据库中有效的服务名称。要找出有效的服务名称，您可以在oracle中使用以下查询:

select value from v$parameter where name='service_names'

有一次我更新了tnsnames。奥拉:

TEST =
   (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = *<validhost>*)(PORT = *<validport>*))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = *<servicenamefromDB>*)
    )
)

然后我就跑:

sqlplus user@TEST

成功! 监听器基本上是在告诉你，不管你使用的是什么service_name，根据DB，都不是一个有效的服务。

(*我从Win7客户端工作站运行sqlplus到远程DB，责怪dba;) *)

对我来说很简单，我只需要在“Windows服务”中手动启动服务。MSC在CMD trompt)。 我的服务名称是:OracleServiceXXXXX。

我已经实现了下面的解决方法来解决这个问题。

我已经使用命令提示符设置了ORACLE_HOME (右键单击cmd.exe并以系统管理员身份运行)。 使用以下命令 设置oracle_home="到oracle home的路径" 进入“所有程序——> Oracle -ora home1——>配置迁移工具——> Net Manager——> Listener” 从下拉菜单中选择数据库服务。 全局数据库名和SID都设置为相同(在我的例子中是ORCL)。 设置“Oracle Home Directory”。

Oracle Net Manager窗口示例:

单击File并保存网络配置。

问题可能在于不正确的URL。

例如，我正在使用Oracle数据库(在VM内部)与Spring框架，并有这个问题。

在我的申请中。属性文件:

spring.datasource.url=jdbc:oracle:thin:@//localhost:1521/orcl12c

但是db版本是不同的:

spring.datasource.url=jdbc:oracle:thin:@//localhost:1521/orclcdb

正确的URL可以在tnsnames中找到。ora文件(这个文件可以在Oracle服务器上找到，所以如果你使用VM，你应该在你的主机VM中寻找这个文件)。 例如，在VirtualBox中查看Oracle文件的命令是:

nano /u01/app/oracle/product/version/db_1/network/admin/tnsnames.ora