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.
Related
I'm considering using SQLite as a production database for a site that would receive perhaps 20 simultaneous users, but with the potential for a peak that could be many multiples of that (since the site would be accessible on the open internet and there's always a possibility that someone will post a link somewhere that could drive many people to the site all at once).
Is SQLite a possibility?
I know it's not an ideal production scenario. I'm only asking if this is within the realm of being a realistic possibility.
SQLite doesn't support any kind of concurrency, so you may have problems running it on a production website. If you're looking for a 'lighter' database, perhaps consider trying a contemporary object-document store like CouchDB.
By all means, continue to develop against SQLite, and you're probably fine to use it initially. If you find your application has more users down the track, you're going to want to transition to Postgres or MySQL however.
The author of SQLite addresses this on the website:
SQLite works great as the database engine for most low to medium traffic websites (which is to say, most websites). The amount of web traffic that SQLite can handle depends on how heavily the website uses its database. Generally speaking, any site that gets fewer than 100K hits/day should work fine with SQLite. The 100K hits/day figure is a conservative estimate, not a hard upper bound. SQLite has been demonstrated to work with 10 times that amount of traffic.
The SQLite website (https://www.sqlite.org/) uses SQLite itself, of course, and as of this writing (2015), it handles about 400K to 500K HTTP requests per day, about 15-20% of which are dynamic pages touching the database. Dynamic content uses about 200 SQL statements per webpage. This setup runs on a single VM that shares a physical server with 23 others and yet still keeps the load average below 0.1 most of the time.
So I think the long and short of it is, go for it, and if it's not working well for you, making the transition to an enterprise-class database is fairly trivial anyway. Do take care of your schema, however, and design your database with growth and efficiency in mind.
Here's a thread with some more independent comments around using SQLite for a production web application. It sounds like it has been used with some mixed results.
Edit (2014):
Since this answer was posted, SQLite now features a multi-threaded mode and write ahead logging mode which may influence your evaluation of its suitability for low-medium traffic sites.
Charles Leifer has written a blog post about SQLite's WAL (write ahead logging) feature and some well-considered opinions on appropriate use cases.
The small excerpt from SQLite website says it all.
Is the data separated from the application by a network? → choose
client/server
Many concurrent writers? → choose client/server
Big data? → choose client/server
Otherwise → choose SQLite!
SQLite "just works" (until it doesn't of course)
We often use SQLite for internal databases; The employee directory, our calendar of events, and other intranet services all run on lightweight databases. It would be major overkill to be running these apps at the scale we do on a "real" database like mySQL. This is especially true when you factor in that they're running along side 4 other virtual machines on a single mid-range computer.
At one point we had an outward facing site that ran on an sqlite db for months with only a single reboot required. Obviously, it was very low traffic, but it putted along nicely for what it did.
We have encountered a similar option on an environment with absolutely no writes, and we selected using SQLite.
See my blog post on the subject:
Well, the main assumption which makes this solution theoretically
possible is that our SQLite database is totally read-only. Our server
code should never change it. This would solve any locking problems, as
there are no read locks. We could find nowhere on the internet anyone
saying there is a problem in high-throughput reading of SQLite when
there are no writes - it could be possible!
I think it would depend mostly on what your read/write ratio will be. If it's mostly reading from the database, you may be okay. Multi-user writing in SQLite can be a problem because of how it locks the database.
People speak about concurrency problems, but sqlite has a way to cache incoming requests and have them wait for some time. It doesn't timeout immediately.
I've read things about the default timeout setting begin zero, meaning it times out immediately and that's nonsense. Maybe people didn't adjust this setting?
Depends on the usage of the site. If most of the time you're just reading data, you can pretty much use anything for a DB and cache the data in the application to achieve good performance.
I am using it in a very low traffic web server (it is a genomic database) and I don't have any problems. But there are only SELECT statements, no writing to the DB involved.
To add to an already brilliant answer: Since you are working with a server-less solution in this case, you can say goodbye to replication, or any sort of horizontal scaling of your db, as well as other advanced options. It also isn't the best choice if you have multiple users updating the same exact chunk of information. If you were to shard the database in the future you would have to migrate the data and move to something else. Also if you have a load balancer and multiple systems involved it would be difficult to maintain data centrality if using sqlite. These are just some of the reasons why it isn't recommended. Its great for smaller projects, and great for development.
It seems like with queuing you could also get away with avoiding a lot of the concurrency write problems with SQLite. Instead of writing directly to the sqlite db you would write to a queue that then in turn sequentially writes to the sqlite db in a first in first out mode. Not sure if your application reaches to where you would need this if it would be worth writing or just moving on to client/server DB...but a thought.
I'm looking for a cross-platform database engine that can handle databases up hundreds of millions of records without severe degradation in query performance. It needs to have a C or C++ API which will allow easy, fast construction of records and parsing returned data.
Highly discouraged are products where data has to be translated to and from strings just to get it into the database. The technical users storing things like IP addresses don't want or need this overhead. This is a very important criteria so if you're going to refer to products, please be explicit about how they offer such a direct API. Not wishing to be rude, but I can use Google - please assume I've found most mainstream products and I'm asking because it's often hard to work out just what direct API they offer, rather than just a C wrapper around SQL.
It does not need to be an RDBMS - a simple ISAM record-oriented approach would be sufficient.
Whilst the primary need is for a single-user database, expansion to some kind of shared file or server operations is likely for future use.
Access to source code, either open source or via licensing, is highly desirable if the database comes from a small company. It must not be GPL or LGPL.
you might consider C-Tree by FairCom - tell 'em I sent you ;-)
i'm the author of hamsterdb.
tokyo cabinet and berkeleydb should work fine. hamsterdb definitely will work. It's a plain C API, open source, platform independent, very fast and tested with databases up to several hundreds of GB and hundreds of million items.
If you are willing to evaluate and need support then drop me a mail (contact form on hamsterdb.com) - i will help as good as i can!
bye
Christoph
You didn't mention what platform you are on, but if Windows only is OK, take a look at the Extensible Storage Engine (previously known as Jet Blue), the embedded ISAM table engine included in Windows 2000 and later. It's used for Active Directory, Exchange, and other internal components, optimized for a small number of large tables.
It has a C interface and supports binary data types natively. It supports indexes, transactions and uses a log to ensure atomicity and durability. There is no query language; you have to work with the tables and indexes directly yourself.
ESE doesn't like to open files over a network, and doesn't support sharing a database through file sharing. You're going to be hard pressed to find any database engine that supports sharing through file sharing. The Access Jet database engine (AKA Jet Red, totally separate code base) is the only one I know of, and it's notorious for corrupting files over the network, especially if they're large (>100 MB).
Whatever engine you use, you'll most likely have to implement the shared usage functions yourself in your own network server process or use a discrete database engine.
For anyone finding this page a few years later, I'm now using LevelDB with some scaffolding on top to add the multiple indexing necessary. In particular, it's a nice fit for embedded databases on iOS. I ended up writing a book about it! (Getting Started with LevelDB, from Packt in late 2013).
One option could be Firebird. It offers both a server based product, as well as an embedded product.
It is also open source and there are a large number of providers for all types of languages.
I believe what you are looking for is BerkeleyDB:
http://www.oracle.com/technology/products/berkeley-db/db/index.html
Never mind that it's Oracle, the license is free, and it's open-source -- the only catch is that if you redistribute your software that uses BerkeleyDB, you must make your source available as well -- or buy a license.
It does not provide SQL support, but rather direct lookups (via b-tree or hash-table structure, whichever makes more sense for your needs). It's extremely reliable, fast, ACID, has built-in replication support, and so on.
Here is a small quote from the page I refer to above, that lists a few features:
Data Storage
Berkeley DB stores data quickly and
easily without the overhead found in
other databases. Berkeley DB is a C
library that runs in the same process
as your application, avoiding the
interprocess communication delays of
using a remote database server. Shared
caches keep the most active data in
memory, avoiding costly disk access.
Local, in-process data storage
Schema-neutral, application native data format
Indexed and sequential retrieval (Btree, Queue, Recno, Hash)
Multiple processes per application and multiple threads per process
Fine grained and configurable locking for highly concurrent systems
Multi-version concurrency control (MVCC)
Support for secondary indexes
In-memory, on disk or both
Online Btree compaction
Online Btree disk space reclamation
Online abandoned lock removal
On disk data encryption (AES)
Records up to 4GB and tables up to 256TB
Update: Just ran across this project and thought of the question you posted:
http://tokyocabinet.sourceforge.net/index.html . It is under LGPL, so not compatible with your restrictions, but an interesting project to check out, nonetheless.
SQLite would meet those criteria, except for the eventual shared file scenario in the future (and actually it could probably do that to if the network file system implements file locks correctly).
Many good solutions (such as SQLite) have been mentioned. Let me add two, since you don't require SQL:
HamsterDB fast, simple to use, can store arbitrary binary data. No provision for shared databases.
Glib HashTable module seems quite interesting too and is very
common so you won't risk going into a dead end. On the other end,
I'm not sure there is and easy way to store the database on the
disk, it's mostly for in-memory stuff
I've tested both on multi-million records projects.
As you are familiar with Fairtree, then you are probably also familiar with Raima RDM.
It went open source a few years ago, then dbstar claimed that they had somehow acquired the copyright. This seems debatable though. From reading the original Raima license, this does not seem possible. Of course it is possible to stay with the original code release. It is rather rare, but I have a copy archived away.
SQLite tends to be the first option. It doesn't store data as strings but I think you have to build a SQL command to do the insertion and that command will have some string building.
BerkeleyDB is a well engineered product if you don't need a relationDB. I have no idea what Oracle charges for it and if you would need a license for your application.
Personally I would consider why you have some of your requirements . Have you done testing to verify the requirement that you need to do direct insertion into the database? Seems like you could take a couple of hours to write up a wrapper that converts from whatever API you want to SQL and then see if SQLite, MySql,... meet your speed requirements.
There used to be a product called b-trieve but I'm not sure if source code was included. I think it has been discontinued. The only database engine I know of with an ISAM orientation is c-tree.
I know that Open Office Database uses a java database backend. Does anyone have any insight on how this compares to the Jet Database Engine?
Also is the query designer/reporting nearly as robust as MS Access?
It's odd for me to say this, because I'm not a fan of Access at all. However, I think Access is actually the nicer product here, for a number of reasons:
It's been around a lot longer (maturity)
The core db engine is included with windows.
There's an easily distributable runtime if your users don't already have Access and you need to distribute an application.
Over the years it's had enough people try to use it for things it's not designed to do (web sites, workgroups) that they've put enough work into performance and concurrency so the two more recent incarnations (2003, 2007) are actually very robust if you're doing something it is designed to do (desktop crud app, talking to linked sql server tables, very small workgroup). (I guess this is really the same as the first point)
On the other hand, there's nothing wrong with the OpenOffice DB, and it's free.
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 would like to build and deploy a database application for Windows based systems, but need to live within the following constraints:
Cannot run as a server (i.e., have open ports);
Must be able to share database files with other instances of the program (running on other machines);
Must not require a DBA for maintenance;
No additional cost for run-time license.
In addition, the following are nice to have "features":
Zero-install (e.g., no registry entries, no need to put files in \Windows\..., etc.);
"Reasonable" performance (yes, that's vague);
"Reasonable" file size limitations (at least 1GB per table/file--just in case).
I've seen this question
Embedded Database for .net that can run off a network
but it doesn't quite answer it for me.
I have seen the VistaDB site, but while it looks promising, I have no personal experience with it.
I have also looked at SQLite, and while it seems good enough for Goggle, I (again) have no personal experience with it.
I would love to use a Java based solution because it's cross-platform (even though my main target is Windows, I'd like to be flexible) and WebStart is a really nice way to distribute software, but the most commonly used DBs (Derby and hsqldb) won't support shared access.
I know that I'm not the only one who's trying/tried to do this, so I'm hoping I could get some advice.
I'd go with SQLite. There are SQLite bindings for everything, and it's very widely used as a embedded database for a large number of applications.
I use SQLite at work and one thing that you should keep in mind is that its file based and uses a file lock for managing concurrent connections. It is not a great solution when you have multiple users trying to use the database at the same time. SQLite is however a great database for one user application, its fast, has a small foot print and has a thriving community built around it.
If you've got VStudio sitting around, how about SQL Server 3.5 Compact edition? MSSQL running in-proc.
http://www.microsoft.com/sql/editions/compact/downloads.mspx