无法从 C# 连接到 Oracle XE 数据库

Question

在此 C# 代码中连接不断超时：

private const string _connectionString = "User Id=c##BookingApp;Password=ftn;Data Source=(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=localhost)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=xe)))";

public static void Test()
{
    using (OracleConnection con = new OracleConnection(_connectionString))
    {
        try
        {
            con.Open();

            OracleCommand com = con.CreateCommand();
            com.CommandText = "SELECT * FROM user_tb;";
            com.ExecuteToStream(System.IO.Stream.Null);

            con.Close();
        }
        catch (Exception ex)
        {
            Console.WriteLine("Error: " + ex.Message);
        }
    }

这是

lsnrctl status

的输出：

LSNRCTL for 64-bit Windows: Version 21.0.0.0.0 - Production on 25-MAR-2024 10:42:12

Copyright (c) 1991, 2021, Oracle.  All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=DESKTOP-08F6LQM)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias                     LISTENER
Version                   TNSLSNR for 64-bit Windows: Version 21.0.0.0.0 - Production
Start Date                15-MAR-2024 15:56:49
Uptime                    9 days 18 hr. 45 min. 23 sec
Trace Level               off
Security                  ON: Local OS Authentication
SNMP                      OFF
Default Service           XE
Listener Parameter File   C:\app\PC\product\21c\homes\OraDB21Home1\network\admin\listener.ora
Listener Log File         C:\app\PC\product\21c\diag\tnslsnr\DESKTOP-08F6LQM\listener\alert\log.xml
Listening Endpoints Summary...
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=DESKTOP-08F6LQM)(PORT=1521)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC1521ipc)))
  (DESCRIPTION=(ADDRESS=(PROTOCOL=tcps)(HOST=DESKTOP-08F6LQM)(PORT=5500))(Security=(my_wallet_directory=C:\APP\PC\PRODUCT\21C\admin\XE\xdb_wallet))(Presentation=HTTP)(Session=RAW))
Services Summary...
Service "7c74ac5f71294090a35b32d2635fdfc9" has 1 instance(s).
  Instance "xe", status READY, has 2 handler(s) for this service...
Service "CLRExtProc" has 1 instance(s).
  Instance "CLRExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "XE" has 1 instance(s).
  Instance "xe", status READY, has 2 handler(s) for this service...
Service "XEXDB" has 1 instance(s).
  Instance "xe", status READY, has 1 handler(s) for this service...
Service "xepdb1" has 1 instance(s).
  Instance "xe", status READY, has 2 handler(s) for this service...
The command completed successfully

我已经尝试了连接字符串的每种变体，但我无法弄清楚为什么它超时。 SQL Developer 中的连接工作正常。

我正在使用

Oracle.ManagedDataAccess.Client

并且我看到有人提到

Oracle.DataAccess.Client

但我找不到合适的软件包，所以我假设这只是

ManagedDataAccess

软件包的旧版本。

Answer 1

您正在连接到：

(HOST=localhost)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=xe))

但你的听众正在听：

(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=DESKTOP-08F6LQM)(PORT=1521)))

我假设 DESKTOP-08F6LQM 未映射到 127.0.0.1。此外，当连接到 Express Edition 时，您通常会在可插入数据库 XEPDB1 中完成所有工作，因此您通常会连接到该数据库，而不是 XE