SQL Server Database Sync Architecture with local computers

Question

I'm developing a project which several terminals which will constantly update to a server database(Host in the cloud or one of the terminal). However, the application should not be stopped if internet down and it should sync automatically (If can) to the server database after internet recover.

Hence apparently, each terminal need have one local database to handle internet down situation.

Experience in developed C# WPF application but new to the database application.

My questions are:

1. Which approach has better reliability? Host in cloud or terminal?

2. Is it better to perform a real-time sync or perform the sync at the end of the day?

3. Do SQL Server Express or Azure database provide auto sync? Or how can I make it auto sync?

Answer 1

In this case you can install a SQL Server Express instance on each terminal and then use SQL Data Sync to make all SQL Server Express instances sync with a hub database you will create on Azure SQL Database. When you configure SQL Data Sync on the "Automatic Sync" section you can specify number of seconds/minutes/hours/days as when the sync should occur. The more frequent you sync the less data you can be lost in case of a disk failure or terminal crash.

To learn more about SQL Data Sync please read here .

Answer 2

1. Create your application and create application database connection for local host.

2. Subscribe for Azure and create a SQL Database.

3. Follow here for on-premise sync. in addition install Microsoft Azure Data Sync Agent Preview 2.0 or above, download here .

4. if you do the above, your application will continue with the local host and sync in to the hub database when only Internet is available. this is called On-Premise Azure SQL Sync.