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I'll give you a bit of background because I don't think my question is clear without it. Aside from that, I don't know much about servers but I think it'll become clear what I'm actually asking because of the background information.
I was/am building a small C++ program to be used by just me (a homework manager, which needed to keep track of tasks, so it relied on tasks and subtasks and needed multiple tables, etc.), so I figured I needed a database. I quickly stumbled upon SQLite, which was perfect for my case in many ways: -it's free, -it only uses .db files which can be interpreted by any software, -it can be embedded, -it's simple (in terms of documentation and libraries), and most importantly: -it is what SQLite.org describes as 'serverless'.
However, I found SQLite's dynamic type system extremely annoying ('why' is besides the point; I might make seperate posts asking questions about this) and I decided to look for a rdbms that has all the pros I mentioned above but also has static typing.
While going down this rabbit-hole of looking for a rdbms to fit my needs, I came across many terms which were all related to how the rdbms is implemented regarding the term 'server' and the like. All the terms are very vagues and one word does not mean the same every instance.
I noticed all of these keywords and contrasts popping up during my search:
Stand-alone vs server/client
Embedded vs... 'not embedded', I guess(?)
Classic serverless vs neo-serverless
Serverless... but in reality cloud-based (I thought clouds were servers(?))
Server vs service
Service vs application
User vs client
I'm as far as to know that a server is a proces that is executing on the background, not to be used by the user directly. But other than that, all these server-related terms are throwing me off.
I want a rdbms that has this 'serverless'ness SQLite.org speaks of. I saw many professional free SQL RDBMS providers which spoke of the ability to have 'embedded servers', which does contain the word 'embedded' but it also contains 'server'. So my question is: when a providers speaks of these 'embedded servers', what does it really mean?
Does it mean that there is one application, and when it runs it opens another application which functions as a server? And when it does so, is that server a service or just another normal application-like process? Or, does it work exactly the same like the serverlessness SQLite mentions, that being: the libraries inside of the compiled project already handle everything to work with only .db files? Does it need any files other than the database and the executable? Does the communication between the application and database file directly come from the code or is another proces used?
(PS: as a side-question: could you help me clear up what all the terms in the list above precisely mean?)
I realise my question might be all over the place, but so is the vocabulary I've come across in this journey. I hope you can understand where my confusion is coming from and can help me clear these points up. Thanks in advance.
By "serverless" SQLLite just means that it's a library, and doesn't run in a seperate process. In this it's like Access/Jet and other older DMBS programs that read and write files directly. The more common term for this is "embedded database".
The more common meaning of "serverless" these days is a cloud-based capability that doesn't require you to install or manage a "server" or VM. As in "We use Azure Functions for serverless compute".
The other DMBS systems are typically called "Client-Server DBMS", where the DMBS runs in a seperate process and the client program communicates with it over a network or some RPC mechanism. Client-Server RDBMS systems can be "bundled" or "embedded" with an application, and may not be running on a seperate computer, but would still be running in a seperate process.
Our company is upgrading all work computers soon and no longer supporting MS Access. Unfortunately, a lot of important database is stored in a plethora of Access databases with many differing styles of interfaces. Storing it all on a database server is out of the question. What is a good portable (non-server) database system that I can use?
The one I'm leaning toward is SQLite, but I'd also like to be able to write interfaces to query the data. If I use SQLite, what is a good way to write a query interface that will work on a lot of Windows machines natively?
EDIT: Data migration will not be a problem. I'm more worried about interface migration. What is a good way to write a query interface for one of these portable database systems?
EDIT2: It seems that there's some confusion as to what I mean by "query interface". I don't need a complete query system. I'm simply looking to create a simple frontend through which I can search the Database by table and by fields.
Judging by the title of your question, you are concerned about what database (i.e. data container) should be used in place of Microsoft Access. However, viewing your question and the ensuing answers and comments, your greater concern is actually what to use to design the Application/user interface, what you are referring to as the "query interface".
Here's a couple things you need to realize:
1) SELECT queries allow you to extract data from a database. However, the data has to get into the database somehow. At no point have you specified whether or not your so-called "query interface" is also used for data entry. If it is in fact used for data entry, as I suspect it is, then you should concern yourself with how your going to design your "application", not your "query interface". Data entry often requires a certain amount of guidance and logic that is defined outside of the database. This logic includes (but is not limited to) things like validation rules, input masks, parent child relationships that are enforced by the GUI design. This is essentially an application, not merely a "query interface". Applications are usually designed to make data entry easier than having the user enter data directly into the tables. But even here you must realize that ultimately a user can't even enter data directly into a table without some type of application GUI, whether that GUI is something you've designed or not.
2) Microsoft Access is a Rapid Application Development (RAD) tool that allows you to quickly and easily design and save queries, forms, and reports. It appears to me that you're real question is, What RAD tool other than Microsoft Access can I use to develop queries and forms for viewing and entering data in small desktop databases? And what database would you recommend we use together with the RAD tool you're recommending?
Assuming I've properly defined your actual question, allow me to give my own viewpoint on this question. First, as has already been pointed out in another answer, as long as the clients are running MS Windows, you don't really need to move away from using Access/Jet/ACC as your database (data container, the part that holds the tables). As long as MDAC is installed an Access database should be "machine readable".
It seems to me the more important question here is what RAD tool should you use in place of Microsoft Access? After you answer this question perhaps it will help you answer the first question, of what database should be used. In answer to this question, let's be honest. While Microsoft Access has it's shortcomings, you probably won't find any other RAD tool that allows you to so easily create Forms for data entry. FileMaker Pro is one of the only competing products that I know of.
Yes, you could use Visual Studio .Net to create .exe runtimes. These runtimes can include forms for viewing and entering data as well as reports. I think you'll find that the learning curve is pretty major, especially if you are not yet familiar with ADO.Net which is very different from DAO or ADO Classic. If you want to give your users ways to create their own queries/filters or reports you'll have to design this functionality into your GUI since Visual Studio doesn't give you the easy wizards and design tools you'll find in Microsoft Access. While Visual Studio is far more powerful than MS Access, you need to realize that the development time for even the simplest of applications is probably going to be much higher, especially when you are first learning.
Are there any other RAD tools you could possibly use? I know little if anything about the different design tools listed here but this might be a good place for you to start: http://en.wikipedia.org/wiki/List_of_rapid_application_development_tools#Desktop_Rapid_Application_Development_Tools
SQLite is a great option and will extend your reach to many platforms beyond Windows (iOS, OSX, Android, etc.). I recommend this. If you want to keep using Microsoft products, SQL Server Express or Compact Edition is another possibility.
Another solution, depending on what you are doing with these databases, would be Microsoft SQL Server Compact Edition which does not require an installer.
No matter what database you choose, you are going to be faced with migrating your queries to a different dialect of the SQL language (the actual syntax of your queries). They all have their quirks and features (and missing features). That is just the nature of the beast. It should be noted that you can still access a MS Access database in code without requiring the installation of MS Access.
It appears that the nature of the question has changed dramatically since it was originally posted. The question has apparently morphed into one about finding an user interface development environment that has similar features to Access. This is obviously an entirely different question than finding a replacement for Access (or specifically Jet for those anal retentives in the audience) as a database engine.
There are many alternatives and it depends greatly on whether you wish to continue with a Windows application or whether you wish to move to a browser based interface. Given various comments, it sounds like you may still want a Windows based solution. A couple of solutions you might investigate:
.NET Windows Forms - The .NET environment is incredibly powerful and provides for very rapid development. IMO, as rapid as Access if you know what you are doing and far more powerful. However, with those additional capabilities comes additional complexity. No question that jumping into Windows Forms from pure Access development will be daunting but rewarding.
Another solution, which I admit to not having tested myself, but looks promising is Kexi + SQLite which is geared as an open source replacement for Access.
If you considered changing gears and switching to a browser based approach, there are again many choices. PHP, ASP.NET (MVC and not), Ruby and so on. As with Windows Forms, switching to browser based development from Access development will be a daunting change but also rewarding.
Of course, if the PHB are eliminating Access as a cost cutting move, you could split the existing Access databases to Front-end/backend applications, migrate the backends to SQL Server Express edition (free) and have the users use the MS Access run-time (also free) You, the developer, are the only one who actually needs a paid-for full version of Access.
This response comes long after the question was posted--but Google still turns it up near the top of results for 'replace ms access'
You should include MySQL and PostgreSQL on your list of the potential replacements. MySQL supports AUTO_INCREMENT columns, so it might be a better replacement for the Microsoft databases. Also, Microsoft SQL Server Express might be not a bad option. I migrated from using MS Access databases to using MS SQL Server Express in my apps when I was using Microsoft technologies about 10-12 years ago.
I'm using delphi for years, but never for database stuff, but recently started researching and testing.
I must say, i'm impressed, most of things happens automatically, i'm used to write by hand in php and python.
i'm going to develop a commercial system for a friend, (2 layers) 5 user computers, 1 database server.
Database server will be a decent machine with (raid-1) 2 hard drives running (MySql5.1 or Postgre or Firebird, open to suggestions).
ADO
Easy to use
Easy deployment (only mysqlconnector installer)
The slower?
DbExpress
Need to ship 4 files [dbxconnections.ini, dbxdrivers.ini, mysqldll, driverdll]
The more complex (harder to use)
ClientDataSet add complexity, but looks really useful
No free Postgre driver?
Zeos
Easy deployment (1 dll)
Easy to use
As you can see the desired features are:
fast
easy to use
easy to deploy
I can't test all in a real scenario (clients, server), so i hope that you guys with experience can help me out in which one to choose and why.
EDIT: Thanks everyone, i think i will go with ADO (probably) or Zeos
Thanks in advance
Arthur
#arthurprs, for you scenario
(2 layers) 5 user computers, 1 > database server.
alt text http://www.techsolusa.com/images/firebird-logo-64.gif The Firebird RDBMS is a very good option , because is very stable, fast, runs on Linux, Windows, and a variety of Unix platforms and meet with you requirements.
alt text http://d.yimg.com/kq/groups/12858579/homepage/name/homepage.jpg Respect to the components for connection i go for ZEOS.
I have used this combination in many small and medium projects, with excellent results.
I have worked on many commercial high volume systems using ADO without any problems. Deployment is relatively simple since its included in the OS. Since it has such a wide audience, most of the major issues have been identified and corrected. Getting help with ADO connectivity is very easy. The database support is very deep (connectionstrings.com) which make supporting additional database engines almost trivial (you may need to still install the client drivers, but that would be the same for almost any solution).
Performance isn't much of an issue, it really will come down to database architecture and engine selection.
id have to say im rather happy with NexusDB but the cost for the client/server versions might not be worth it.
it works client/server or fully embedded, simple enough you can have both in your app and switch between them, depending on your clients needs
the embedded DB is free,
client/server "Priced per developer" is AU$ 500
No cost per install.
Oh yeh and its written in delphi ;)
I'd say to go with Firebird - is the most used database engine in the Delphi land (see here). For connectivity perhaps is better to go with Zeos (free) or DBX (if you can afford the Architect version - the only one who has the Firebird driver in it).
About ADO: Mature connectivity layer but it will be (forever - most probably) tied to Windows while Delphi will go cross-platform. Also, yes, it tend to be the slower one because of many reasons, including the ODBC drivers which are used in certain situations. But in your case, of course, as skamradt says, I don't think that it will matter so much.
Although I have read people not liking the idea of mixing the two, I have had good results using ADO Datasets as a "provider layer" which then feeds the data into TClientDataSets - so there's no reason you can't use ClientDataSets if you go down the ADO route if you find you need them (and they are useful).
Otherwise, I would echo the comment that ADO is a tried, trusted mechanism that isn't going anywhere. I've always found it more than fast enough. And configuration using UDL files is nice and easy.
dbGo (ADO) is more simple to manage, more universal, more slow
dbExpress is more fast, more complex to manage, supports less DBMS's
ZeosDBO is simple to manage, universal like dbExp, slow like dbGo, cross-platform, has few additional components, all sources are accessible
There are few other libraries, resolving all above doubts, although all of them are commercial products. But there I am biased :)
We have used postgreSQL using Devart pg components with great success in medium sized database apps.
We did some limited benchmarking with this combination and found it 2-3 x the speed of using ADO etc.
-- Data access components
I too favour the combination of TClientDataset and ADO. Had worked with it in past and I can say it's trustful. The flexibility of TClientDataset is a big gain. DBExpress is good too.
Actually, I use clientdatasets with pretty much any data access layer that have an TDataset descendant...
-- Server
Firebird. Free and easily usable from OLEDB (I used with ODBC) and DBExpress (D2010+ have native DBX driver) - don't know ZEOS, but I believe that it also connect to FB.
Scale well to many connections and big databases. There are databases on Firebird with 500Gb and many users reported.
I am creating a desktop app in Delphi and plan to use an embedded database. I've started the project using SQlite3 with the DISQLite3 library. It works but documentation seems a bit light. I recently found Firebird (yes I've been out of Windows for a while) and it seems to have some compelling features and support.
What are some pros and cons of each embedded db? Size is important as well as support and resources. What have you used and why?
I'm using Firebird 2.1 Embedded and I'm quite happy with it.I like the fact that the database size is practically unlimited (tested with > 4 GB databases and it works) and that the database file is compatible with the Firebird Server so I can use standard tools for database management and inspection. Distribution consists of dropping few files in your exe folder.
Simultaneous access from multiple programs is not supported but simultaneous access from multiple threads is (as long as you ensure that only one 'connect' operation is in progress at any given moment).
I have used SQlite3 for a lot of projects (but from C/C++ and Objective-C). It's extremely small -- no dependencies whatsoever -- database is in a single file.
It's the db of choice for Mac developers because it's directly supported by CoreData and on the iPhone -- so there is a big user base (not to mention all of the other users).
I've been using SQLite (via DISQLite3) in FeedDemon for several months, and I highly recommend it - it has been extremely fast and stable. As Javier said, the docs for the library may be thin, but the docs for SQLite itself are very good.
I've used DBISAM on a number of projects. It is completely embedded without even a need for an external DLL. Unlike the others you listed it is commercial. A lot of great features though and very well documented and supported. The have a successor to it that I haven't tried yet though.
Let's see, quick comparison:
SQLite:
dynamic typing in the database
cross-platform files
runs on Windows, Linux, Mac, etc.
public domain
supports transactions
relies on file system security, does not include own security
Firebird embedded:
strong typing in the database
not all SQL datatypes are supported
cross-platform files
Firebird embedded only runs on Windows
Files from Firebird embedded are in the same format as the full server version
Files from Firebird embedded can be copied to a non-Windows server for use
available under a modified MPL ("what's ours is ours and must remain free, what's yours is yours and you don't have to release it")
supports transactions, triggers, etc.
MySQL embedded:
support for SQL features depends on file format
(IIRC) cross-platform files
GPL unless you pay royalties
runs on Windows, Linux, Mac
incredibly popular with the open source crowd
Even embedded databases have their strengths and weaknesses. You'll need to weigh those strengths and weaknesses against what you're doing to decide.
Firebird embedded is our #1 choice because with no code changes, a single user Delphi app with embedded database can be migrated to a multi-user server based deployment without sacrificing any of the high end features (such as stored procedures, triggers, views, etc.). And its a TRUE free database and doesn't GPL your code in the process.
Strongly recommend to use AnyDAC when working with Databases and Delphi - then you can choose to target FB or SQLite seamlessingly.
My preference would be for FB for embedded apps.
Tom
I use Sybase's Advantage Database Server, but I'm also the R&D Manager, so this post is biased. :)
We have native Delphi TTable and TQuery components for both WIN32 VCL and VCL.NET. Direct table access in addition to SQL support makes Advantage unique among many of the other Delphi offerings. Advantage supports large tables (only limited by the number of records, 2 billion) and has a free local engine, which is nice for development PCs and for small customer sites that don't require client/server functionality. Switch to client/server with a single connection property, no other changes.
We have a ton of clients so accessing the data outside of Delphi is also very easy (.NET data provider, ODBC, OLE DB, PHP, Perl, JDBC, etc).
Main Product Web Site: http://www.advantagedatabase.com
Developer's Web Site: http://devzone.advantagedatabase.com
It really depends what you need. For single-user applications, Firebird Embedded or SQLite are probably best choices (and price is right). On the other end, if you need support for large number of multiple users, you should probably use regular Firebird instead of Embedded version (server is simple to install so you won't have much problems here).
And if you need something in between, for a moderate multi-user application, one of flat databases would be better. I found that ComponentAce's Absolute Database better choice for my needs than DBISAM, NexusDB or VistaDB.
It leaves relatively small footprint (no DLLs), it's a single-file db (a must for me), supports Unicode, BLOB compression, crypting, and technical limits seem impressing for a flat database. Moreover, support was good in few occasions when I needed it.
For cons, I have noticed it doesn't support nested transactions, but other than that, I had no problems.
As for size, nothing beats SQLite.
when you refer about lack of documentation, i guess it's doc for DISQLite3. The SQLite docs are quite complete
Take a look at NexusDB. Have used very successfully in the past.
The problem with (embedded) firebird is, that the database cannot reside on a network drive. Also, it is difficult to have a database on a read only drive (CD/DVD).
For some hacks around these limitations see the Delphi Wiki:
http://delphi.wikia.com/wiki/Firebird_tipps
NexusDB offers the full range from embedded, to full client/server / remote. Also SQL2003 compliant, I believe. I'm using it on a few projects, and am very pleased so far, and the fact that it can work in such a wide range of "scales" is a big plus (not having to learn another DB for scaled-up apps, etc).
Look at this embedded database comparison: http://sql-db.cz.cc/, it can be helpful. Most of abovementioned products are presented there: Advantage, DBISAM, Firebird, MS SQL Server, and much more: Accuracer, Apollo, ElevateDB, NexusDB, TurboDB.
I am partial to Component Ace's Absolute DB. Although a commercial product ($), it is solid, easy to use, small footprint and well documented. If you are looking for a huge multi-user application, this is not the way to go, but if your multi-user needs are light (or non-existent) this is a solid option.
I'm using SQL Server Express and the ADO components. Works great. You can run the SQL Server Express install with commandline to hide the complexities from the users. You can also distribute a database that you load by filename. There are millions of SQL server users so solutions to any problems are easily found in the intertubes :-)
I did a websearch to find a fast database package for my Delphi Application. I wanted it to be completely contained in the executable with no external DLLs or libraries required. I originally found Accuracer by AidAim. They had posted how fast their database was and even gave comparisons with other similar packages to “prove” their point.
I wanted to believe their claims but I thought I’d search the web a bit more to find timings of other packages. I was very surprised to find a post at the Delphi discussion forums where a person asked what database to use, and there were 14 different suggestions. One of the responders had done his own timing comparisons and had found Accuracer to be quite slow compared to several others, which Accuracer had (conveniently) left out of their own comparison page.
The post, plus additional followup web research by me, led me to lean toward DISQLite3, a product based on the Open Source SQLite program, but with enhancements to work in Delphi very quickly, with very small overhead, and with command-based calls - which I like. It is actively under development and will soon have an official Delphi 2009 version, although apparently the current version will work under D2009.
Addenum: DISQLite3 Version 2.0.0, released Nov 17, supports D2009.
I know MS access is a comparatively crap db (and expect to be shot down in flames here), but if only small data is needed it may have advantages if ms office is used anyway. For me it was a way to store program data with more flexibility than csv files which is a common approach for scientific code.
You can create an access db from delphi code without having ms office installed using ado & odbc driver (might be necesary to have an initial .accdb file without tables to copy from then populate, I can't remember this detail. not sure licensing situation doing this.
The .accdb extension can be changed to something else & the file password protected (to a limited degree) so its not immediately obvious to users its access if that's desired.
I know a few commercial developers do this method & copied it myself. Found it easier to setup than sqlite, but maybe because I'd already used ado & access in the past.
I have used ScimoreDB. It has its quirks as they give it royalty free and it has its quirks in data types and with some installation issues. This was on a C# project.
If embedded is an absolute must, look at DBISAM.
kbMemTable is a good candidate. Runs in memory, fast, multi-threadding. Used to be free.
Components4Developers
I have used DBISAM and kbMemTable on different occasions.
What I like about DBISAM is that it has great features, and is usually very reliable. I have used it in large databases, full-text search, read-only mode, CGIs and many other situations.
It is fairly large compared to kbMemTable or SQLite based components, though. And you can't have a single file per database (or even table) - depending on the situation, that is a major disadvantage.
kbMemTable is tiny and it's great for small amounts of data. Since it runs in memory, it has to be a small amount of data, of course.
One other option I've taken on a couple of my desktop apps is dumping the data directly from/to my object hierarchy using TWriter/TReader. This is by far that smallest option, and is absurdly fast compared to using a database. The data files are tiny, too.
It has all kinds of drawbacks, though - you have to code versioning in if you might want to ever add/change fields, unless it's in-memory it is even more complicated, no multi-user support at all, etc.
Firebird embedded is our #1 choice as well. And the suite Unified Interbase v2.0 with it. A great and stable solution!
I have a database that I have to record 5 field data for every 20 sec for 10 days.. 3 field are integer , 1 field is double ( time ) and 1 field is string[5].
I am still using Delphi6 srv2 because of my components. Newer delphi versions are terrible at components that I have to spend thousands of dollars of money to rebuild my component library. Therefor delphi 6 is still best for real commertial applications that never version of delphis give many problems. At many points such as USB or comport readings so on... they release newer ones before previous versions never sit on market.
I have setup a code with Delphi6 what appends 43200 records at a table for test because I will deploy the table in application while it has 43200 records. I will shown all the data on DBChart.
Test result is below databases filled the tables by insert command with 43200 records
Dbisam = 34 sec,
ElevateDb = 11 sec,
AbsoluteDB = 45 sec,
SQLlite = 32 Minute,
Firebird = 12 min,
MSSQL12 localDB = 28 Minute,
Easy table = 8 minute,
BDE = Blocked ,
I havent tested oracle , blackfish , sysbase, nexsusDb etc.. but it seems they will also very slow. I have connected with DBChart and only elevateDb and absoluteDB has loaded 43200 records on DBchart in exceptable time such as 7~10 secs. Other all taken minutes. So slower databases always needs coding tricks to succeed in some real jobs..
I have tested their search speed as well by locate command that unfortunatly the server based databases are always slower in.
MSSQL and SQLLite3 are extremely difficult to manage in to delphi that they made me very tired.
These are my test results
At the end I decided to use AbsoluteDB, Dbisam and Elevate. I have thrown the rest off the PC .
Elevate software doesnt support recno function that requires extra codes at runtime to manage. This makes the database slower Other bug is with Elevate software is autoinc fields. There is no way to reset it . Therefore I have not chosen the Elevat software even it is the fastest database. They say many good functions but how many of them we use it in fact . They just left the most important functions not supported but fixed many many unnecessary functions. and it seems since 8 years there is no any advantage either.
If you want to see with your own eye pls just try and see..
I am thinking between two now absolute DB or DBisam4
Firebird all the way. Does pretty well everything and so far version 2.1 is very solid.
FireBird offers the opportunity to scale up to multi-users sometime down the line, or if you need concurrency (if your application goes multi-threaded).
SQLite is quite unrivaled if you only need single-user access, no other database comes close to it on any aspect, be it performance, convenience, SQL support or stability.
Firebird is really awsome and has a small footprint so you can use embedded
and it can be scaled upward for many users
and does unicode faily well
I use devart components with delphi 2009
and FIB plus for delphi 6/7 (their version for 2009 and unicode is not ready yet too bad)
Hmmm, no one has recommended the BDE - I wonder why that is ;-)
BlackFishSQL is another possibility, although I haven't tested in depth as yet.
when it comes to embedded databases the first question is : is it multiuser ?
Actually,who needs a database that does not allow multiple connections (read&write) to it ?
I have tried (intensly) all mentioned databases and found only one that actually functions the way it should. And that is Accuracer.
The only pity with accuracer is that its a three man band and chronic lack of proper support. It also is mainly static in development as we have seen no real features in years.Not surprising since only one person actually develops it. It seems they are living on old fame. Users praise reflect that (usually 10 years old comments).
For a single user experience I would recommend Absolute Database.
As for major players I would recommend SQL Server from Microsoft. Oracle has become a bloatware and is slowly dying out.
ps
what is nice in accuracer is that their embedded database functions just like full blown server. It locks only current record if its in use while the rest functions normally. Nice database. Pity only it is stagnant.
I need a database that could be stored network drive and would allow multiple users (up to 20) to use it without any server software.
I'm considering MS Access or Berkeley DB.
Can you share your experience with file databases?
Which one did you use, did you have any problems with it?
I really don't think that file-based databases can scale past half a dozen users. The last time I had an Access database (admittedly this was quite a while ago) I had to work really hard to get it to work for 8-9 people.
It is really much easier to install Ubuntu on an old junk computer with PostgreSQL or MySQL. That's what I had to do even when I kept my Access front-end.
I would suggest SQLite because the entire database is stored in a single file, and it quite safely handles multiple users accessing it at the same time. There are several different libraries that you can use for your client application and there is no server software needed.
One of the strengths is that it mimics SQL servers so closely that if you need to convert from using a database file to a full-fledged SQL Server, most of your queries in your client won't need to change. You'll just need to migrate the data over to the new server database (which I wouldn't be surprised if there are programs to convert SQLite databases to MySQL databases, for example.)
Beware of any file based database, they are all likely to have the same problems. Your situation really calls for a Client/Server solution.
From SQLite FAQ
A good rule of thumb is that you
should avoid using SQLite in
situations where the same database
will be accessed simultaneously from
many computers over a network
filesystem.
http://www.sqlite.org/whentouse.html
Access can be a bitch. Ive been in the position where i had to go around and tell 20-50 people to close access so I could go to "design mode" to change the design of the forms and maybe a column. No fun at all. (Old access, and it might just be a bad setup)
Ayende was recently trying to make a similar decision, and tried a bunch of so-called embedded databases. Hopefully his observations can help you.
I have been using Access for some time and in a variety of situations, including on-line. I have found that Access works well if it is properly set up according to the guidelines. One advantage of Access is that it includes everything in one package: Forms, Query Building, Reports, Database Management, and VBA. In addition, it works well with all other Office applications. The Access 2007 runtime can be obtained free from here, which makes distribution less expensive. Access is certainly unsuitable for large operations, but it should be quite suitable for twenty users. EDIT: Microsoft puts the number of concurrent users at 255.
Can Access be set up to support 10-20 users? Yes. It, as well as all file-based databases use the file system for locking and concurrency control, however. And, Access data files are more susceptible to database corruption than are database servers. And, while you can set it up for this, you MUST, as David Fenton mentions above, follow best practices, if you want to end up with a reliable system.
Personally, I find that, given the hoops that you need to jump through to ensure that an Access solution is reasonably trouble-free, it is much less trouble to implement an instance of MSDE/SQL Server Express, or postgreSql.
Berkeley DB supports a high degree of concurrency (far more then 20), but it does so primarily by utilizing shared memory and mutexes (possibly even replication) - facilities that do not work well when BDB is deployed as a file stored on a network drive.
In order to take advantage of DBD concurrency capabilities you will have to build an application around it.
The original question makes no sense to me, in that the options don't belong together. BerkeleyDB is a database engine only, while Access is an application development tool that ships with a default file-based (i.e., non-server) database engine (Jet). By virtue of putting Access with Berkeley, it seems obvious that what is needed is only a database engine, and no application at all, but how end users use Berkeley DB without a front end, I don't know (I've only used it from the command line).
Those who cannot run a Jet MDB with 20 simultaneous users are simply not competent to be giving advice on using Jet as a data store. It is completely doable as long as best practices are followed. I would recommend in addition to Microsoft's Best Practices web page, Tony Toews's Best Practices, and Tony's Corruption FAQ (i.e., things you want to avoid doing in order to have a stable application).
I strongly doubt that the original questioner is building no front end application, but since he doesn't indicate what kind of front end is involved, it's hard to recommend a back end that will go with it. Access has the advantage of giving you both parts of the equation, and when used properly, is perfectly reliable for multiple users.