How does a local server access the cloud database SQL Server?

A local server can access a cloud database SQL Server through a secure network connection, typically using the internet or a private network. The process involves configuring the local server to communicate with the cloud-hosted SQL Server instance by specifying the correct connection details, such as the server's IP address or hostname, port number, database name, and authentication credentials (username and password or other authentication methods).

Steps to Access a Cloud SQL Server from a Local Server:

Ensure Network Connectivity: The local server must have internet access or a VPN connection to the cloud provider's network if the SQL Server is hosted in a private virtual network.
Configure SQL Server for Remote Access: The cloud SQL Server must be configured to allow remote connections. This involves enabling TCP/IP protocol in SQL Server Configuration Manager and setting up firewall rules to allow traffic on the SQL Server port (default is 1433).
Set Up Authentication: Use SQL Server Authentication (username and password) or Windows Authentication, depending on the setup. For cloud environments, SQL Server Authentication is commonly used for flexibility.
Use Connection String in Applications: The local server's applications (e.g., web apps, desktop apps) must use a connection string that points to the cloud SQL Server. Example connection string:
```
Server=your-cloud-sql-server.database.windows.net;Database=your-database;User Id=your-username;Password=your-password;
```
Test the Connection: Use tools like SQL Server Management Studio (SSMS) or a simple script to test the connection from the local server to the cloud SQL Server.

Example Scenario:

A company has a local development server and uses a cloud-hosted SQL Server for production data. Developers on the local server need to access the production database for testing. They configure their local SSMS or application to connect using the cloud SQL Server's public endpoint (e.g., mydb.cloudsqlprovider.com,1433) and their credentials.

Recommended Tencent Cloud Services:

For cloud-hosted SQL Server needs, Tencent Cloud offers TencentDB for SQL Server, a fully managed relational database service. It provides high availability, automated backups, and scalability. To securely connect a local server to TencentDB for SQL Server, you can use:

Tencent Cloud Virtual Private Network (VPN) or Direct Connect for secure private network access.
Public Endpoint with proper firewall rules and security groups for internet-based access.

Example of connecting via public endpoint in a .NET application:

string connectionString = "Server=my-tencent-sql-server.database.tencentcloudapi.com,1433;Database=mydb;User Id=myuser;Password=mypassword;";
using (SqlConnection connection = new SqlConnection(connectionString))
{
    connection.Open();
    // Perform database operations
}