German Viscuso

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Does Jease still support db4o? Congrats!

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You should switch to db4o so there's nothing to clean =)

Jan: nice project but it's a key/value store not an object database. In a key value store you're forced into an abstraction introduced by the persistence mechanism (eg. working with a hashmap). That's something you don't have to do with an oodb, if you were working with collections, you just keep using them transparently except that you make them them persistent (in db4o for example you have "transparent persistence") and you keep all your object references while at it. IMHO oodbs are closer to the language (feel more integrated with it and natural)

Jan: nice project but it's a key/value store not an object database. In a key value store you're forced into an abstraction introduced by the persistence mechanism (eg. working with a hashmap). That's something you don't have to do with an oodb, if you were working with collections, you just keep using them transparently except that you make them them persistent (in db4o for example you have "transparent persistence") and you keep all your object references while at it. IMHO oodbs are closer to the language (feel more integrated with it and natural)

Jan: nice project but it's a key/value store not an object database. In a key value store you're forced into an abstraction introduced by the persistence mechanism (eg. working with a hashmap). That's something you don't have to do with an oodb, if you were working with collections, you just keep using them transparently except that you make them them persistent (in db4o for example you have "transparent persistence") and you keep all your object references while at it. IMHO oodbs are closer to the language (feel more integrated with it and natural)

Jan: nice project but it's a key/value store not an object database. In a key value store you're forced into an abstraction introduced by the persistence mechanism (eg. working with a hashmap). That's something you don't have to do with an oodb, if you were working with collections, you just keep using them transparently except that you make them them persistent (in db4o for example you have "transparent persistence") and you keep all your object references while at it. IMHO oodbs are closer to the language (feel more integrated with it and natural)

Jan: nice project but it's a key/value store not an object database. In a key value store you're forced into an abstraction introduced by the persistence mechanism (eg. working with a hashmap). That's something you don't have to do with an oodb, if you were working with collections, you just keep using them transparently except that you make them them persistent (in db4o for example you have "transparent persistence") and you keep all your object references while at it. IMHO oodbs are closer to the language (feel more integrated with it and natural)

Jan: nice project but it's a key/value store not an object database. In a key value store you're forced into an abstraction introduced by the persistence mechanism (eg. working with a hashmap). That's something you don't have to do with an oodb, if you were working with collections, you just keep using them transparently except that you make them them persistent (in db4o for example you have "transparent persistence") and you keep all your object references while at it. IMHO oodbs are closer to the language (feel more integrated with it and natural)

Hi Lucas. I believe it's the other way round, first the mapping (table <-> object) process takes time and second db4o uses b-tree indexes for fast access. I can verify this on a simple benchmark that compares db4o vs SQLite where db4o is faster (taken from a benchmark published by the guys that provide Perst). If you want to actually try the benchmark please contact me privately and I'll send it to you.

Moreover the simplicity and time saved are pretty obvious here: http://developer.db4o.com/Projects/html/projectspaces/android_password_manager.html (see the code comparisons, the video sucks)

Best!

Hi Lucas. I believe it's the other way round, first the mapping (table <-> object) process takes time and second db4o uses b-tree indexes for fast access. I can verify this on a simple benchmark that compares db4o vs SQLite where db4o is faster (taken from a benchmark published by the guys that provide Perst). If you want to actually try the benchmark please contact me privately and I'll send it to you.

Moreover the simplicity and time saved are pretty obvious here: http://developer.db4o.com/Projects/html/projectspaces/android_password_manager.html (see the code comparisons, the video sucks)

Best!

Hi Lucas. I believe it's the other way round, first the mapping (table <-> object) process takes time and second db4o uses b-tree indexes for fast access. I can verify this on a simple benchmark that compares db4o vs SQLite where db4o is faster (taken from a benchmark published by the guys that provide Perst). If you want to actually try the benchmark please contact me privately and I'll send it to you.

Moreover the simplicity and time saved are pretty obvious here: http://developer.db4o.com/Projects/html/projectspaces/android_password_manager.html (see the code comparisons, the video sucks)

Best!

Hi Lucas. I believe it's the other way round, first the mapping (table <-> object) process takes time and second db4o uses b-tree indexes for fast access. I can verify this on a simple benchmark that compares db4o vs SQLite where db4o is faster (taken from a benchmark published by the guys that provide Perst). If you want to actually try the benchmark please contact me privately and I'll send it to you.

Moreover the simplicity and time saved are pretty obvious here: http://developer.db4o.com/Projects/html/projectspaces/android_password_manager.html (see the code comparisons, the video sucks)

Best!

Hi Lucas. I believe it's the other way round, first the mapping (table <-> object) process takes time and second db4o uses b-tree indexes for fast access. I can verify this on a simple benchmark that compares db4o vs SQLite where db4o is faster (taken from a benchmark published by the guys that provide Perst). If you want to actually try the benchmark please contact me privately and I'll send it to you.

Moreover the simplicity and time saved are pretty obvious here: http://developer.db4o.com/Projects/html/projectspaces/android_password_manager.html (see the code comparisons, the video sucks)

Best!

Hi Lucas. I believe it's the other way round, first the mapping (table <-> object) process takes time and second db4o uses b-tree indexes for fast access. I can verify this on a simple benchmark that compares db4o vs SQLite where db4o is faster (taken from a benchmark published by the guys that provide Perst). If you want to actually try the benchmark please contact me privately and I'll send it to you.

Moreover the simplicity and time saved are pretty obvious here: http://developer.db4o.com/Projects/html/projectspaces/android_password_manager.html (see the code comparisons, the video sucks)

Best!

Hi Eric. Nice use of generics, I believe it quite works to simplify the example. But I agree that using interfaces so that you can plug in whatever persistence provider you want might be overkill for Android (can't really say until we see code).

Best.

Hi Eric. Nice use of generics, I believe it quite works to simplify the example. But I agree that using interfaces so that you can plug in whatever persistence provider you want might be overkill for Android (can't really say until we see code).

Best.

Hi Eric. Nice use of generics, I believe it quite works to simplify the example. But I agree that using interfaces so that you can plug in whatever persistence provider you want might be overkill for Android (can't really say until we see code).

Best.

Hi Eric. Nice use of generics, I believe it quite works to simplify the example. But I agree that using interfaces so that you can plug in whatever persistence provider you want might be overkill for Android (can't really say until we see code).

Best.

Hi Eric. Nice use of generics, I believe it quite works to simplify the example. But I agree that using interfaces so that you can plug in whatever persistence provider you want might be overkill for Android (can't really say until we see code).

Best.

Hi Eric. Nice use of generics, I believe it quite works to simplify the example. But I agree that using interfaces so that you can plug in whatever persistence provider you want might be overkill for Android (can't really say until we see code).

Best.

Hi Eric. Nice use of generics, I believe it quite works to simplify the example. But I agree that using interfaces so that you can plug in whatever persistence provider you want might be overkill for Android (can't really say until we see code).

Best.

Hi Eric. Nice use of generics, I believe it quite works to simplify the example. But I agree that using interfaces so that you can plug in whatever persistence provider you want might be overkill for Android (can't really say until we see code).

Best.

Here's he page on IDs with db4o: http://developer.db4o.com/Documentation/Reference/db4o-7.12/java/reference/html/reference/implementation_strategies/ids_and_uuids.html Best!

=D Awesome! This comment made my day, thanks a lot!

Here's a nice thread about a refactoring question (on Stackoverflow):

http://stackoverflow.com/questions/2420248/handling-data-maintenance-in-object-databases-like-db4o

This article is mentioned in this developer podcast (minute 8):

http://techcast.chariotsolutions.com/index.php?post_id=590881

Hi mssimor, thanks a lot.

Let me point you in the right direction:

db4o works well on Android, performance is good. Of course you'll have to add the jar file to your Android project. For more info see the Android section on developer.db4o.com where you'll find a link to MapMe, a db4o based app available on the Android Market including source code. You might also want to take a look at the Android section on the db4o docs.

With regards to refactoring, db4o handles some scenarios automatically (eg. adding a member to a class). Please take a look at the refactoring page on the db4o docs

I also would like to add that db4o is compatible with several open source licenses (not only the GPL) via the dOCL.

Best!

German

Hi mssimor, thanks a lot.

Let me point you in the right direction:

db4o works well on Android, performance is good. Of course you'll have to add the jar file to your Android project. For more info see the Android section on developer.db4o.com where you'll find a link to MapMe, a db4o based app available on the Android Market including source code. You might also want to take a look at the Android section on the db4o docs.

With regards to refactoring, db4o handles some scenarios automatically (eg. adding a member to a class). Please take a look at the refactoring page on the db4o docs

I also would like to add that db4o is compatible with several open source licenses (not only the GPL) via the dOCL.

Best!

German

Hi mssimor, thanks a lot.

Let me point you in the right direction:

db4o works well on Android, performance is good. Of course you'll have to add the jar file to your Android project. For more info see the Android section on developer.db4o.com where you'll find a link to MapMe, a db4o based app available on the Android Market including source code. You might also want to take a look at the Android section on the db4o docs.

With regards to refactoring, db4o handles some scenarios automatically (eg. adding a member to a class). Please take a look at the refactoring page on the db4o docs

I also would like to add that db4o is compatible with several open source licenses (not only the GPL) via the dOCL.

Best!

German

Why not???

??? It's a relaunch of the website, the community site has been around for many years.

New entry in the series "db4o: Queries in Java or Queries Without LINQ" http://www.gamlor.info/wordpress/?p=744

Or you can just work with an oodbms and forget all about this...

Or you can just work with an oodbms and forget all about this...

The review lacks information on which programming language (or languages) are used in the code examples. Also, do you get full source code for the samples?

Best.

It's db4o (with an o) not db40. Can you change the title? Cool stuff! =D

The part where they discuss the db4o challenge is right in the end of the podcast

By the description the reader won't realize that db4o now supports transparent persistence! (but it's mentioned in the full article)

In the case of db4o you should try embedded client/server to have multiple transactions (and this mode doesn't involve networking): http://developer.db4o.com/blogs/product_news/archive/2007/09/15/embedded-client-server-performance-improvements.aspx Best!

As I said db4o IS gpl. If you think you're not violating the gpl go ahead and use db4o man! On the other hand db4o commercial license is exactly as the OEM commercial license of MySQL: http://www.mysql.com/company/legal/licensing/ (if you dig around the MySQL site you'll see that they monetize their database, there's a sales department and everything). You must understand that commercial and open source is not a contradiction anymore (you can have truly open source projects that have a company behind!!) With regards to "noone uses it" I completly disagree. There're more than a 100 projects using db4o under an open source license (noone of these are paying for db4o): http://projects.db4o.com

db4o is no different than almost any other dual licensed open source software (MySQL, Trolltech. etc) And with regards to price it's really affordable compared to popular DB vendor commercial licenses. What do you want? To use db4o for free in your commercial application and never give anything back to the community? db4o didn't invent the GPL, it was there long before db4o even existed and it's the most popular open source license. db4o IS gpl no matter whether you like the commercial licensing policies or not.