Database Deployment Practices

I have deployed plenty of software to my clients. Mostly are Window Forms applications. Here is my current practice.

1. Manually install SQLExpress and SQL Management Studio to each client PC.
2. Then use ClickOne to install the code from the server.
3. When there is a changes in code, I will use ClickOne to deploy -(NO PROBLEM with this step)
4. But when there is a change in a database column, what do I do?

I have even tried writing a database update script. Each time the program 开发者_如何学编程starts, it will read through the .sql update file and run them if the database exists. This solves the problem of updating the database columns, but it does not help in my DEBUGGING work when my customer complain there is a wrong data. At that point, I have to personally go to their site to check it out.

I find it difficult to have the database installed on the client PC as it make my debugging work very very difficult. I am thinking about moving my client database to a host on an Online server. But that then comes with these constraints:

1. What if the internet is down?
2. What if my customer has no internet?

Could you help to advise me? Is this a common problem faced by developer? What is the common practice out there? Does Window Azure or SQL CE help?

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Depending on the data I would recommend using SQL CE. If the data isn't too much, speed is not the primary goal (CE is slower than Express) and you don't need DB-Features not supported by CE (e.g. stored procedures) it is the better choice IMHO, because:

• The client does not need to install a full SQL server (easier installation/deployment)
• You do not have problems with multiple SQLExpress instances
• Your SW doesn't need to worry if there even is a SQL instance
• Less resources used on the client side

Additionally the clients could send you their SQL CE DB-File for inspection and you do not need to go to their site.

It is also relativly easy to implement an off site sync with SQL CE and MS Sync FW.

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Installing one database per client PC can be tricky. I think you have a decent handle on how to deal with the issue currently. It seems like the real issue you are currently facing is debugging. To deal with this, there are a couple ways you could go:

1. Have the customer upload their copy of the database back to you. This would provide you with the data they have and you could use it with a debug copy of your code to identify the issues. The downside is that if the database is large it might be an issue transferring it.
2. Remote onto the customer's machine. Observe the system remotely using something like CoPilot. That way you could see what is happening in its natural environment.

There are probably other ways, but these are a couple of good ones. As for using an online database, this is an option but it brings its own set of issues with it. You mentioned a couple. As for Azure, that is cloud-based (online) so the same issues will apply. SQL CE won't help you any more than your current installation does.

Bottom line is that I would recommend you look into the ways to fix your one issue (as listed above) instead of creating a whole new set of issues by moving to an Internet-based solution. I would only recommend moving to the Internet if it was addressing a larger business need (for example, mobility). Doing the same thing you have been doing only online will probably just make life harder.

To recap the comments below since they are so pertinent to the issue, if you are choosing between file-based databases that don't need to be physically installed on the machine, your best choices are probably between SQLite and SQL CE. Microsoft supports SQL CE better but it is a larger package and has less features than the trim SQLite. Here is a good discussion on the differences:

https://stackoverflow.com/questions/2278104/sql-ce-sqlite-what-are-the-differences-between-them

However, the issue gets more complicated when you start looking at linq2sql since that is designed for SQL server. Microsoft does not support SQL CE with linq2sql out of the box, although there is a work-around that will get it to work:

http://pietschsoft.com/post/2009/01/Using-LINQ-to-SQL-with-SQL-Server-Compact-Edition.aspx

SQLite is not supported at all with linq2sql but there is a way to use linq to talk with SQLite:

LINQ with SQLite (linqtosql)

This library also supports other common databases including MySQL and Firebird.

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You could use the SQLCMD utility to execute the change script, as mentioned in this related question