TNS（Transparent Network Substrate）是Oracle数据库网络层的一部分，用于定义客户端和数据库服务器之间的连接。以下是一个基本的TNS连接字符串的格式：

```

tnsname = (DESCRIPTION =

[简化描述]

[详细描述]

)

```

简化描述

简化描述通常包含服务名或连接标识符，格式如下：

```

tnsname = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = host_name)(PORT = port_number)))

```

`PROTOCOL`：连接协议，通常是TCP。

`HOST`：数据库服务器的IP地址或主机名。

`PORT`：数据库监听的端口号，默认为1521。

例如：

```

tnsname = (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = dbserver)(PORT = 1521)))

```

详细描述

详细描述提供了更详细的连接信息，包括数据库服务名、监听器信息和连接选项。格式如下：

```

tnsname = (DESCRIPTION =

[监听器信息]

[服务信息]

[连接选项]

)

```

监听器信息：

```

(ADDRESS = (PROTOCOL = TCP)(HOST = host_name)(PORT = port_number))

```

服务信息：

```

(SERVICE_NAME = service_name)

```

连接选项（可选）：

```

(CONNECT_DATA =

(SERVER = DEDICATED)

(SERVICE_NAME = service_name)

(FAILOVER = (TYPE = SELECT) (RETRIES = 3) (DELAY = 5))

)

```

例如：

```

tnsname = (DESCRIPTION =

(ADDRESS = (PROTOCOL = TCP)(HOST = dbserver)(PORT = 1521))

(CONNECT_DATA =

(SERVICE_NAME = my_service)

(FAILOVER = (TYPE = SELECT) (RETRIES = 3) (DELAY = 5))

)

)

```

请根据您的具体需求调整上述示例中的信息。希望这对您有所帮助！