Feeling a little bad, two questions from you guys in a week!

So I am about to embark on a project including Point of Sale, Inventory Management, Client management, (quite in depth).

The difference is any information regarding Clients will be stored locally throughout the day and then uploaded to external servers allowing any customer to access an up to date online account of their purchases.

The current competitors use .mdb files to store their data, which is fine, but we would prefer to use MySQL (or possibly PostgreSQL if that's how you spell it). Is it possible to create a solid file and run a MySQL database from it? Like StoreDB.MYSQL?

And also, if there are going to be 5 computers all accessing the one database through the network in the store, is running from a file the best way to go? Or would it be better to run some sort of server on the host computer and access that from the slaves?

Any thoughts?

Why don't you use Microsoft SQL Server? You need to run an SQL Server as an application on a server and have the clients connect to it.

You can get a free version of MSSQL. I do not advocate any of the Linux databases although they will work. You will need to get an OleDb or ODBC driver for the database you choose and use OleDbConnection or OdbcConnection.

If you use MSSQL they have a native driver so you can use SqlConnection.

I do like the fact that MSSQL has LINQ, which I have become very fond of (mysql does too but i'm not that keen on it).

I have heard that MySQL is quicker? (This was the main reason I was after it), in terms of a main server that is being updated at the end of the night from 800 systems around the country don't I need speed (and a small footprint)?

If you read pro-MSSQL benchmark tests then MSSQL is faster, if you read pro-mySQL benchmarks then mySQL is faster. Use MSSQL. You will be saving yourself a lot of heartache down the road. You can easily scale mssql to what you have described.