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Which DB? Linq to SQL classes

I want to develop a multiuser supporting accounting management application in C#.
I want to use Linq To SQL classes. LINQ to SQL only supports SQL Server/Compact. However is it possible the SQLite people have written their own LINQ provider given the name of the assembly.
I have to use DBMS that is FREE. Which DBMS do you suggest to me?

LIN2SQL = SQL Server. Second class badly written O/R mapper compared to the real contendors (like NHibernate).
LINQ2SQL != LINQ. LINQ is the query integration into the langauge, and supported by pretty much a lot of O/R mappers out there, and some databases.
I have to use Db that is FREE.
Free like for free? What is against sql server? Express edition - 0 USD. And the 4gb "database size limit" does not stop you from writing accounting systems. THat is a LOT of space for accounting data. For many years of accounting data.

If you want to use Linq-to-SQL (which I think is an excellent choice) you have to use some variant of MSSQL. Both Sql Server Compact and Sql Server Express are free to use. If you have a multiuser scenario you will have to go for Sql Server Express as Sql Server Compact doesn't allow multiple simultaneous access.

There are various experimental linq to sql and linq to entity framework providers for other databases(like mysql and postgres) - in my experience they are so immature it is not worth using for anything serious.
For now, I'd suggest you'd look for something else if you cannot use SQL server.

Try the following link:
http://sqlite.phxsoftware.com/
Note that Linq2SQL is not compatible with SQLite, however the link points to an Entity Framework provider for SQLite. EF is kind of like Linq2SQL on steroids. SQLite is very lightweight, so the EF implementation above should work nicely for your needs.

how to generate dbml file from Sybase database?

I think we may have trouble with our existing project. For some reasons we have to switch from SQL Server to Sybase SQL Anywhere 11. now we trying to find a way continue use our existing LINQ code.
We wish we can still use L2S? If cannot, we wish we can use L2E, then we have to change to ADO.
how to generate dbml file from Sybase Anywhere 11? after that can we use sqlmetal to generate .cs files?

Linq to SQL only supports MS SQL Server. You might consider switching to Entity Framework if this is an option and if there is a provider fro Sybase SQL Anyware.
As far as I know there are also no plans to extend the Linq to SQL support to other databases, especially as MS pushes EF as the future database technology.

How do I use an Embedded database with the Entity framework?

I was wondering about the use of the .NET entity framework with an embedded database solution. Right now, I only use the EF with SQL Server but for a new project I'm looking for alternate solutions. SQL Server Compact would be one solution, but are there other alternatives that I can use with EF? Preferably solutions that don't require complex installations?

The actual (although not the full one) list of ADO.NET Entity Framework providers is available here.
There is a couple of providers supporting Embedded MySQL - dotConnect for MySQL and MySQL Connector/NET and SQLite - dotConnect for SQLite and System.Data.SQLite.

If there is an EF provider for the embedded database, you should be able to plug it right into EF. Check with your embedded database provider to see if they have support for EF.
Third Party Provider Support for the Entity Frameworkhttp://blogs.msdn.com/adonet/archive/2008/08/11/third-party-provider-support-for-the-entity-framework-rtm.aspx

Alternative to SQL Server for a simple web app

I have a simple app written using SQL Server, Entity Framework, C# and WCF. When I wanted to share this app with my friends, I realised they didn't use SQL Server on their machine. I could go for SQL Server Express edition, as the usage of my app is personal and non-commercial.
I found MySQL as a popular alternative to SQL Server.
1) Would I be required to update my entities when moving to MySQL?
2) Should I anticipate code changes in my BL layer due to change in entities layer? (I am wondering whether entities was built for SQL Server)
Are there any databases similar to MS Access that is lightweight compared to MySQL?
Are there any databases that need not be installed but can be copied around like MS Access?
Appreciate your response!

Sounds like you want SQLite.
SQLite is a software library that
implements a self-contained,
serverless, zero-configuration,
transactional SQL database engine.
Very easy to deploy. Also, check out System.Data.SQLite.
According to the System.Data.SQLite page ...
Supports nearly all the entity
framework functionality that Sql
Server supports, and passes 99% of the
tests in MS's EFQuerySamples demo
application.
You should be good. :)

Im not sure how your BLL looks like and i have no experience with entity framework, but ive experienced multiple times that linq-to-sql works much better with sql-server as with any other database.
So unless you have a good reason not to use sql express, i'd advice to stick to sql express.
After all, you should always install something when deploying (unless you use xml as storage, which is quite well possible with linq-to-xml).

VistaDB Express Edition is also free for non-commercial usage and integrates good into .NET and VS. afaik it also works on a single local data file thus requires no specific installation on your friends' computers.
Otherwise I recommend using PostgreSQL over MySql since it is more standards compliant and has a nicer license.

I think what you're after is just a change in providers. What you need to use MySQL is the .Net Connector which supports most everything simple. It's not very mature yet so something very complex you may have issues on, but it should do most of what you want through Entity Framework.
With Entity Framework yes you can do updates, it's LINQ-to-SQL that doesn't update against any other databases (unless you use a third party provider like DotConnect)
SQLite is one alternative, but since multiple threads against it can cause major issues with it's operation, so if you need a major data store I'd go SQLExpress or MySQL.

Yes, you could use MySql with EF but I don't know if it would require changes.... I wouldn't be surprised if it does though. At the very least your physical DB would have to be ported / converted to MySql and that will take time.
I would assume that if you need to install a DB on your friends Pc's why not stick with SQL Express since you already developed in SQL Server on your box. Should be less issues with this than migrating to MySql.

I'd also vote for VistaDB 3 as it's so easy to deploy.

How do you use LINQ with Sqlite

Would someone explain how to get LINQ working with Sqlite.

Here you have an SQL Linq provider for SQLite, and some other DBs

Joe Albahari's LINQPad now supports Sqlite: http://www.linqpad.net/Beta.aspx. The one LINQ tool to rule them all.

The link provided by CMS doesn't work anymore. I have used this one as it now seems to be baked into their SQL lite ADO .NET provider.
Unfortunately they still don't support the designer mode of VS for creating classes :(
Also be aware that SQL Server compact doesn't support the design mode for LINQ classes! However if you want to use the entity framework the designer does work for SQL lite and SQL Server compact :)

Yup there is a SqlLite Linq Provider as mentioned by CMS
Check out SQL server compact and it works well with Linq
There is another thread on SO which you should check

I would like to add that you can use Linq to Sql with SqlLite with a couple of stipulations:
You cannot use the Linq to Sql designer which means you have to hand roll your classes.
You have to be careful not to do certain operation which will result in Sql code which is not supported by SqlLite.
For example, you cannot use FirstOrDefault() in any of your Linq queries because it will result in something like:
select top 1 * from table where ...
Since SqlLite doesn't support the "top 1" syntax, you will gt a runtime Sql error.
Other than that, I have been using Linq to Sql with SqlLite with great success for basic CRUD operations.

You can use this: http://code.google.com/p/dblinq2007.
Although it looks like the project is still in Alpha stage, IMO it is actually very stable now. Of course if you have a huge project, it is better to consider using something else like MySQL or SQL Compact. I don't like SQL Server, because it is too bloated, and offers not many more functionalities over SQL Compact or MySQL

Check this provider:
SqlLite Linq Provider
Also you can consider using SQL Compact which has very good LINQ-to-SQL support.

On this time there is NO good tools to do this!
LINQ providers for SQLite all is in alpha stage (for example:dblinq2007). And it is very big risk to use it in commercial purpose! So maybe in future...
If you want ot use ADO.NET there is good ove: phxsoftware.