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Do I need to run a server to achieve database-like functionality?

I'm currently trying to develop a program which stores lots of data, similar to an address book, I suppose, with the intent that new data will be periodically added to the program over time.
I know that I could set up a SQL server, and have the program interface with that, but if I want to share my program with other people, I can't guarantee that they'd have access to the server, or that they can set up a server of their own to hold the data.
I also know that I could simply hard-code all of the data into instantiated objects, but that is inelegant, and promises to be incredibly irritating to alter or maintain.
Is there someway I could design the program in such a way that it maintains a database-like structure, yet has no reliance on external programs (such as a SQL server)?

"SQLite is a software library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine."
http://www.sqlite.org/

Sure. You can use XML. XML can be also used as a datasource for ASP.NET components, just like a database.

You could use a flat file database like SQLite which is linked in on compile and could be distributed with your code.

You have several options:
Use flat-file database like SQLite (ADO.NET provider)
Save your data into a file in some format like XML or CSV, or use binary serialization (or something more elaborate if you don't want to have all the data in memory)
Have a public SQL server accessible from the internet

Of course these is always SQL Server express from MS for this purpose.

no you do not neet a server. the most flexibel solution would be to use NHibernate with FluentNHibernate.
There are different drivers for different databases like SQlite, MsAccess and also for Server like MsSql, Oracle, ....

Which data access methodology should I use for this c# console app + Access 2007 scenario? I want Linq!

Here's our situation.
We're receiving a dump of relational data in Access 2007 format. There are quite a few tables involved. We're writing a console app in c# to run various queries against this data. We only need read-only access - we're not updating the Access database.
I haven't used Access in a project since pre-Linq days, and I'm hoping we don't have to go back to coding strings of sql against an ADO.Net connection just because the database is Access. I gather Linq 2 Sql is out of the question, but might Entity Framework be usable?
How would you approach this problem?
EDIT: The console app will be dropped by a business analyst into a folder containing the Access database, and when run will generate a text file created by querying the data. So unfortunately it's not an option to transfer the data to Sql beforehand!

If you must keep the data into Access, you can pull it into a Dataset via ADO.NET, and then use the LINQ extension methods that work against a Dataset to work against the data.
It's not nearly as nice as working with SQL Server, but it does work.

I would fully import the data into Sql Server, after which I would gleefully destroy all copies of the original Access file. Then you could get as Linq-y as you like.

Linq2Sql no, LinqXml yes! How hard would it be to dump the access file to xml?

I'm not sure I understand the question, but have you considered a SQL Server linked server to the Access file? You could then use SQL Server to do the manipulation. I don't know what the limitations/pitfalls of that are, but it's a solution often suggested when there's no good direct way to manipulate the Jet/ACE database.

Simple, linq-able, file based database

Hey, what's the easiest way to use a file-based database with LINQ in C#? It would be best if I could use it without installing extra components.
EDIT: I want to use it for a file index. Not the whole file system, but the database should be not too slow and not too big.

I'd recommend MS SQL Server Compact Edition. Its embedable, small footprint, good performance and you can use Linq2Sql to query it easily. Also it integrates well with Visual Studio IDE and SQL Management Studio.

Are you opposed to using XML?
That's basically what XML is (or, rather, is a major use of XML), and Linq to XML is very powerful.

The way i've implemented this kind of thing previously is to load a csv file into a C# List structure (couldn't say which is best without information on the data), and use Linq to access data from there.
This may not be the best solution for you, but you have given limited information on what you're looking for.

You will always need to install database drivers to talk to a specific database. The only way to avoid that is to create your own driver to talk to a database, or even create your own database engine.
However, both SQLite and VistaDB have LINQ to SQL now. Other alternatives are to use a text file or XML file for your "database."

Store Relational database as XML

I have to store relational data (text, numbers and pictures) into an XML file. I want to maintain the relationship between data and the tables structure.
How do I go about doing that?
My Windows Mobile application use Windows Communication Foundation (WCF) to get data. Once it gets the data it stores them into an XML file.
The WCF use ADO.NET Entity Framework to data retrieve.
I'm going to use SQL Server 2008.
The data will be use to show it on application. I don't want to use SQL Server CE to store data because it's slower. Maybe, instead of using XML file I can use text plain files to store texts and numbers, and image files to store images.
In short, XML will be a way to store the data instead using SQL Server CE or WCF.
Thank you!

Thanks for the additional detail.
My suggestion is first, try SQL Server CE. It might not actually be slower for what you're doing. The time you save in not reinventing the wheel might be better spent in speeding up other parts of your application.
For the rest, assuming you don't need to store the data for long, nor do much with it, I'd suggest copying the data from the Web Service return type into a DataSet. The DataSet type has a WriteXml method that can save the data, and a ReadXml method that can read it back in.

While it's a little ambiguous what is needed, you can try looking into 'FOR XML EXPLICIT' under SQL Server. This will include relationships. Link: http://www.eggheadcafe.com/articles/20030804.asp

what about a dataset ? define the tables and relations, load the data into the dataset, and save it as XML (WriteXml method)

Define your XML format as an XSD. If you use Visual Studio use add new DataSet and the "custom tool" will automagically create a strong-typed set of classes based on DataSet. You can define tables and relations with constraints. It is easy to do in Visual Studio. If you are Visual Studio averse, you can create the XSD by hand and use xsd.exe to generate your code.
Once you have the strong-typed DataSet filled with data you can serialize it to an XML stream by calling WriteXml.

What do you mean by, "maintain the relationship between data and the tables structure"? Are you talking about more than maintaining the ID of a source database record in an attribute of an XML node? What do you need to do with the XML data once you have it? Will it be edited and have to be re-applied to the database?
More questions than answers from me....sorry.

What SQL Server are you using? Some servers allow you to request an XML response for a query. That could save you a lot of work.
EDIT: Since you have specified that you will use MSSQL 2008, you may be in luck. In MSSQL 2005 and later there is a "FOR XML" keyword which allows you to get results as XML. Give it a try.

Serverless Database in C#

Complete newbie question here: I'm just playing with C# for the first time and want to make a Windows Forms application which stores some info in a database structure, but obviously don't want to require something like MySQL to be installed on each client's computer. How do I go about this?

You can use SQLite. It doesn't require any installation or server on the client's computers. Here is an blog describing how to use it with .NET. It is easy to use, just add a reference to the System.Data.SQLite.dll.
Here is an open source data provider for .NET: System.Data.SQLite
From homepage: "SQLite is a software library that implements a self-contained, serverless, zero-configuration, transactional SQL database engine. SQLite is the most widely deployed SQL database engine in the world. The source code for SQLite is in the public domain."

You use a database that doesn't require an install. There are a few out there - there's Microsoft SQL Server Compact, which frankly is badly named, as it won't support the more useful SQL functions like stored procedures, views and so on. There's also VistaDB which does support stored procs, but requires purchase if you want Visual Studio plugins.

The answer is Embedded Databases. You've got quite a large list of Embedded databases that you can use:
Commercial:
VistaDB - This database is written completely in managed C#.
Open Source:
Firebird - .NET Driver
SQLite - .NET Driver

You could write your data to XML files, or you could take a look at the Sql Server Compact Edition.
You could also work with objects and serialize/deserialize these to disk as binaries.
Of course the type of storage you choose depends a lot on the kind of data you're storing (and the volume of it).

Use SQL Server CE

An easy way to do it from .NET 3.5 onwards is to store your data in XML files and use Linq to XML. This allows you to use SQL-like commands on your data which are actually compiled into your application, so you get full IDE IntelliSense support and error checking.

Perhaps you could serialise a dataset and save it as XML. I'm a little confused why if you're playing around you would need to install MySQL on all client's computers. You could look at using SQL Express which is free perhaps?
Serialise Dataset:
http://blogs.msdn.com/yosit/archive/2003/07/10/9921.aspx
http://msdn.microsoft.com/en-us/magazine/cc163911.aspx

The Easiest way will be SQL Server Compact, Because it integrates directly into the Visual Studio IDE (I'm just hazarding the guess here that you use VS). Add the "Local Database", Create your tables and be sure to make your Table Adapter with Select, Update, Insert and Delete methods. If during Database Creation you called your Dataset "DS" you will be able to instantiate a Table Adapter Object from
DSTableAdapters
Namespace, and Use GetData() or Fill() methods to retrieve your Data, and Insert(), Update() and Delete() to Manage it.

VelocityDB works in a server less mode but can also be combined with a server when there is a need for it. It outperforms all the other choices mentioned here by roughly a magnitude, see comparison here. It allows you to use almost any .NET data structures persistently. The entire database engine and the optional server is implemented using C# code.