Posts Tagged ‘Firebird’
Firebird has a feature allowing you to specify tables you want to lock (read or write and exclusive/protected/shared) when starting transaction. (Note that Firebird still uses MGA/MVCC. This is just a feature to support some scenarios.) We had constants in ADO.NET Provider for Firebird for some time, but using them resulted in wrong parameters being sent to the server and followed by exception. 
Today I implemented support for this locking (tracker item, mailing list thread). That means sending proper sequences. The FbTransactionOptions class created earlier for timeout support was extended with new property LockTables. You can use to specify table name and lock specification. The lock specification there is in fact only subset of all options you can specify for transaction (same enumeration). You can put there whatever you want other options will be simply ignored.
Small example:
conn.BeginTransaction(new FbTransactionOptions()
{
TransactionBehavior = FbTransactionBehavior.ReadCommitted, // etc.
LockTables = new Dictionary<string, FbTransactionBehavior>
{
{ "TABLE_1", FbTransactionBehavior.LockWrite | FbTransactionBehavior.Shared },
{ "TABLE_2", FbTransactionBehavior.LockWrite | FbTransactionBehavior.Exclusive }
}
});
Here I’m specifying that for TABLE_1 shared (huh ) write lock will be placed and for TABLE_2 exclusive (that sounds better, isn’t it?) write lock will be placed. Similarly you can go with LockRead.
Available right now in weekly builds and SVN.
There’s a lot of content for latest CTP, CTP4, for Entity Framework “new features”. It’s mainly focused on Code First stuff, that fills the triad with Database First and Model First. I like Code First but what I also like is maintainable code. Hence I was more trying not to use convention-over-configuration, in opinion good for only small projects, and focus on specifying everything the way I want it to be, especially with my database structure (yes, I’m data consistency and storage freak).
Let’s model some kind of simple library and try to use there couple of Entity Framework’s features. And to make things worse, try to do it with ADO.NET provider for Firebird.
Good news is I succeeded. My database structure was my first and non-touchable object (to be honest the first was the idea what to create and how to represent it in database) together with the idea of objects.
Here’s the script for Firebird database (Did you noticed we’re fully Entity Framework 4 compatible?). See the quoted column names? Yes, not nice, but later in mapping in C# it looks nicer. 
And I mixed the mapping with one for MS SQL Server (see below).
RECREATE TABLE Authors (
"id" INT NOT NULL,
"FirstName" VARCHAR(255) NOT NULL,
"LastName" VARCHAR(255) NOT NULL,
CONSTRAINT PK_Authors PRIMARY KEY ("id")
);
RECREATE TABLE Books (
"id" INT NOT NULL,
"Discriminator" char(2) NOT NULL,
"Title" VARCHAR(1000) NOT NULL,
"Published" TIMESTAMP NOT NULL,
"ID_Author" INT NOT NULL,
"IssuesPerYear" SMALLINT,
"Price" DECIMAL(9,0),
CONSTRAINT PK_Books PRIMARY KEY ("id")
);
RECREATE TABLE Languages (
"id" INT NOT NULL,
"LanguageName" VARCHAR(100) NOT NULL,
"LanguageAbbrevation" CHAR(3),
CONSTRAINT PK_Languages PRIMARY KEY ("id")
);
RECREATE TABLE Translators (
"id" INT NOT NULL,
CONSTRAINT PK_Translators PRIMARY KEY ("id")
);
RECREATE TABLE Translators_Languages (
"ID_Language" INT NOT NULL,
"ID_Translator" INT NOT NULL,
CONSTRAINT PK_Translators_Languages PRIMARY KEY ("ID_Language", "ID_Translator")
);
ALTER TABLE Books ADD CONSTRAINT FK_Book_Author FOREIGN KEY ("ID_Author")
REFERENCES Authors("id")
ON DELETE CASCADE
;
ALTER TABLE Translators_Languages ADD CONSTRAINT FK_TL_Languages FOREIGN KEY ("ID_Language")
REFERENCES Languages("id")
ON DELETE NO ACTION
;
ALTER TABLE Translators_Languages ADD CONSTRAINT FK_TL_Translators FOREIGN KEY ("ID_Translator")
REFERENCES Translators("id")
ON DELETE NO ACTION
;
ALTER TABLE Translators ADD CONSTRAINT FK_TypeConstraint FOREIGN KEY ("id")
REFERENCES Authors("id")
ON DELETE NO ACTION
;
So it’s time to create mapping right? Nope. Now I’ll switch my brain from ER thinking into OO thinking mode. Here’s the world of entities (sure I made some adjustments to fit some Entity Framework features, like Complex Types):
public abstract class Book
{
public int ID { get; protected set; }
public string Title { get; set; }
public DateTime Published { get; set; }
public Author Author { get; set; }
public int AuthorID { get; set; }
}
public class RealBook : Book
{
public decimal Price { get; set; }
}
public class Magazine : Book
{
public short IssuesPerYear { get; set; }
}
public class Author
{
public int ID { get; protected set; }
public Name FullName { get; set; }
public ICollection<Book> Books { get; set; }
public Author()
{
this.Books = new List<Book>();
}
}
public class Translator : Author
{
public ICollection<Language> Languages { get; set; }
public Translator()
{
this.Languages = new List<Language>();
}
}
public class Language
{
public int ID { get; protected set; }
public string LanguageName { get; set; }
public string LanguageAbbrevation { get; set; }
}
#region Complex Types
public class Name
{
public string FirstName { get; set; }
public string LastName { get; set; }
}
#endregion
As you see I’m using pure POCOs.
So far we haven’t touched any Entity Framework related stuff. So it’s time to create our context and all DAL related stuff. Mine is very simple and exposes only few properties and methods, just to keep it simple and focus on the aim.
public class LibraryContext : DbContext
{
public LibraryContext(DbConnection connection)
: base(connection)
{
this.ObjectContext.ContextOptions.LazyLoadingEnabled = false;
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Configurations.Add(new BookConfiguration());
modelBuilder.Configurations.Add(new AuthorConfiguration());
modelBuilder.Configurations.Add(new TranslatorConfiguration());
modelBuilder.Configurations.Add(new LanguageConfiguration());
modelBuilder.Configurations.Add(new NameConfiguration());
}
public string CreateDatabaseScript()
{
return this.ObjectContext.CreateDatabaseScript();
}
public IDbSet<Book> Books
{
get { return this.Set<Book>(); }
}
public IDbSet<Author> Authors
{
get { return this.Set<Author>(); }
}
}
public class DoNothingWithMyDatabase<TContext> : IDatabaseInitializer<TContext>
where TContext : DbContext
{
public void InitializeDatabase(TContext context)
{ }
}
Pretty simple, isn’t it. I’m using new stripped down objects DbContext (← ObjectContext) and IDbSet/DbSet (← IObjectSet/ObjectSet).
You may also notice, I’ve created object which implements IDatabaseInitializer. That’s because, by default, Entity Framework will try to create database for you and check whether your database matches model (CreateDatabaseOnlyIfNotExists). I‘m controlling my database. You have to add somewhere into your application before doing anything with the context call to SetInitializer:
Database.SetInitializer(new DoNothingWithMyDatabase<LibraryContext>());
And finally we’re ready to dive into the mapping. Again, you can type the mapping directly into overridden OnModelCreating, useful if you have only couple of diversions from default conventions. I created configuration classes where I specified as much as I want. And I need (almost) everything to be nailed down (remember, data consistency and storage freak ) as I don’t want to be surprised when something in database or in entities changes and application will start behave weird.
class BookConfiguration : EntityConfiguration<Book>
{
public BookConfiguration()
{
this.HasKey(x => x.ID);
this.Property(x => x.ID).IsIdentity();
this.Property(x => x.Title).IsRequired().IsVariableLength().HasMaxLength(1000).IsUnicode();
this.Property(x => x.Published);
this.HasRequired(x => x.Author).WithMany(a => a.Books).WillCascadeOnDelete().HasConstraint((b, a) => b.AuthorID == a.ID);
this.MapHierarchy()
.Case<Book>(x => new
{
id = x.ID,
Title = x.Title,
Published = x.Published,
ID_Author = x.AuthorID,
})
.Case<RealBook>(x => new
{
Discriminator = "B",
Price = x.Price,
})
.Case<Magazine>(x => new
{
Discriminator = "M",
IssuesPerYear = x.IssuesPerYear,
})
#if FB
.ToTable("BOOKS");
#else
.ToTable("Books");
#endif
}
}
class AuthorConfiguration : EntityConfiguration<Author>
{
public AuthorConfiguration()
{
this.HasKey(x => x.ID);
this.Property(x => x.ID).IsIdentity();
this.HasMany(x => x.Books);
this.MapHierarchy(x => new
{
id = x.ID,
FirstName = x.FullName.FirstName,
LastName = x.FullName.LastName,
})
#if FB
.ToTable("AUTHORS");
#else
.ToTable("Authors");
#endif
this.MapHierarchy().Case<Translator>(x => new
{
id = x.ID,
})
#if FB
.ToTable("TRANSLATORS");
#else
.ToTable("Translators");
#endif
}
}
class TranslatorConfiguration : EntityConfiguration<Translator>
{
public TranslatorConfiguration()
{
this.HasMany(x => x.Languages).WithMany()
#if FB
.Map("TRANSLATORS_LANGUAGES",
#else
.Map("Translators_Languages",
#endif
(t, l) => new
{
ID_Translator = t.ID,
ID_Language = l.ID,
});
}
}
class LanguageConfiguration : EntityConfiguration<Language>
{
public LanguageConfiguration()
{
this.HasKey(x => x.ID);
this.Property(x => x.ID).IsIdentity();
this.Property(x => x.LanguageName).IsRequired().IsVariableLength().HasMaxLength(100).IsUnicode();
this.Property(x => x.LanguageAbbrevation).IsFixedLength().HasMaxLength(3).IsUnicode();
this.MapSingleType(x => new
{
id = x.ID,
LanguageName = x.LanguageName,
LanguageAbbrevation = x.LanguageAbbrevation
})
#if FB
.ToTable("LANGUAGES");
#else
.ToTable("Languages");
#endif
}
}
class NameConfiguration : ComplexTypeConfiguration<Name>
{
public NameConfiguration()
{
this.Property(x => x.FirstName).IsRequired().IsVariableLength().HasMaxLength(255).IsUnicode();
this.Property(x => x.LastName).IsRequired().IsVariableLength().HasMaxLength(255).IsUnicode();
}
}
I don’t know whether it’s worth to describe the lines. Should be understandable if you know how the entities and database look like. Just maybe small notice. Besides Complex Types we used two most common inheritance mapping scenarions – TPH aka Table Per Hierarchy for Books and TPT aka Table Per Type for Authors (there’s also TPC (Table Per Concrete Type)). However if you have questions feel free to use comments, if I’ll know answer I’ll be happy to reply.
And finally some really simple application to test the result:
If you define #define FB it’ll use Firebird database else MS SQL Server.
Database.SetInitializer(new DoNothingWithMyDatabase<LibraryContext>());
Action<LibraryContext> doSomething = (context) =>
{
Console.WriteLine(context.CreateDatabaseScript());
var query = context.Books
.Select(b => new
{
BookName = b.Title,
AuthorName = b.Author.FullName.LastName + ", " + b.Author.FullName.FirstName
})
.OrderBy(x => x.BookName);
Console.WriteLine((query as ObjectQuery).ToTraceString());
var data = query.ToArray();
foreach (var item in data)
{
Console.WriteLine("Book {0} written by {1}.", item.BookName, item.AuthorName);
}
};
#if FB
using (LibraryContext context = new LibraryContext(new FbConnection(@"database=localhost:ctp4;username=sysdba;password=masterkey;pooling=true;")))
{
doSomething(context);
}
#else
using (LibraryContext context = new LibraryContext(new SqlConnection(@"Data Source=.\sqlexpress;Initial Catalog=ctp4;Integrated Security=True;Pooling=False;MultipleActiveResultSets=True")))
{
doSomething(context);
}
#endif
I’m glad I was able to figure out how to map everything without touching database structure (although it’s pretty straightforward) or letting the default rules to kick in. Hope it will help you if you struggle with something (and hope the naming will not change much in future). It’s also nice to see the whole infrastructure fits together and changing provider, in my case for Firebird’s, doesn’t make the code to blow out.
Scott Guthrie recently posted article about New Embedded Database Support with ASP.NET. This made me think about other options, Firebird in particular, and advantages and disadvantages. What I’m going to do is to very shortly introduce Firebird Embedded here and then compare it with features Scott wrote in his article.
Firebird Embedded, shortly, is Firebird database server in one DLL. No need to install etc., just load this DLL and use it. To be precise, there are some other DLLs, i.e. to support national charsets, but it’s still in under 10MB all. The database itself is built from same sources as “full” server and it’s not limited in any way.
Works with Existing Data APIs – as I said, Firebird Embedded is based on same codebase as “full” server, thus the SQL and API is same. And not only this, the ADO.NET provider for Firebird works with it and you’re programming using same thinking.
No Database Installation Required and Database Files are Stored on Disk – databases created by Firebird Embedded are stored wherever you want, with any extension. Firebird itself doesn’t have any master database, thus even the “full” server works with any (valid database) file.
Shared Web Hosting Scenarios Are Now Supported with SQL CE 4 – sure you don’t need to install anything with Firebird Embedded, that’s why it’s called Embedded. And not only this, from version 2.5, you can open database from different processes, i.e. IIS worker process and Apache workers or some console application doing something in background.
Visual Studio 2010 and Visual Web Developer 2010 Express Support – as the tool set for Firebird Embedded is exactly same as for “full” Firebird, you can use DDEX (aka Server Explorer support), Entity Framework (LINQ), …
Supports Both Development and Production – this is something I’m silently expecting. But yes, you can do the same with Firebird Embedded too.
Easy Migration to SQL Server – ahh, my favorite point. The Firebird Project has of course whopping number of tools to support migration from Embedded to “full”. The most used is … nothing. The databases are fully compatible and you can switch servers without any other tools, migration, conversion, … Just place it where you want it and connect to it, either with “full” or Embedded Firebird. And to switch your application? Again nothing. Same ADO.NET provider, just change connection string, if needed. Mostly you’ll add server IP address and maybe different path and manually switch server type, if you want. Really the migration is so simple. It is one minute task and thanks to same tool set, no matter what you version your targeting during development, your application will work with the other as well without any additional effort.
You like Firebird Embedded? I do, a lot. SQL Server Compact Edition 4 looks promising, but Firebird has something to offer as well. And recall, it’s based on same sources as “full” Firebird, very mature codebase, examined with tons of installations.
The ADO.NET provider for Firebird now fully supports all the new features in Entity Framework 4. Simple. If you’re eager to test it, grab the weekly build and enjoy.
We support the internal improvements as well as the visible changes like i.e. Model First or CreateDatabaseScript method. The template for creating SQL script is now part of sources and sure will be included in final package as well. I expect to improve it on your feedback and also the model generation from designer is pluggable so you can create custom one and use it there.
To support some new features in SQL generation I had to tweak it little bit and as with every change, there’s a change that something goes wrong. Thus I would be more than happy to get some feedback either that it works OK or any queries where it fails.
I’m so happy to cross this milestone about two months after final Visual Studio 2010, .NET Framework 4 (incl. Entity Framework 4) were released. You can expect the official release after some testing, it’s your turn .
As it may look like nothing is going on, it’s not true. Next to Firebird 2.5 new protocol features, I’m also working on Entity Framework v4 support. Before I go further, be sure, that all providers written for Entity Framework v1 are also working with v4.
In fact right now all the major improvements in Entity Framework v4 are supported. You can benefit from features available, like the LIKE translation support or plenty of new functions. My personal favorite is TruncateTime (so I can get rid of workaround). The Model First approach is next in a row. At least basic T4 template for start is my aim. The rest could be done by you, simply modifying the template. And also wiring the template into code so you can use it programmatically too. Under the cover, while working on new stuff I’m also finding ways to optimize the code. Luckily the changes will be noticeable.
The DDEX for Firebird supports Visual Studio 2010 and the full Entity Framework v4 support will be here soon – now you can try a weekly build. Feel free to ask about anything related.
The soon to be released Firebird 2.5 has a new ability to cancel running command (or any operation currently being processed by server) via API (in 2.1 you can do it via monitoring tables). This is a nice feature, interesting not only for database administration tools.
I was working on supporting it for a while in .NET provider, but I’m happy to say that it’s done (though I may tune the boundaries based on feedback). From some initial proposal in list I picked one following the design of SqlClient, as it’s a de facto standard in ADO.NET world.
So right now you can do:
using (FbConnection conn = new FbConnection(@"database=localhost:rrr.fdb;user=sysdba;password=masterkey"))
{
conn.Open();
//conn.DisableCancel();
//conn.EnableCancel();
using (FbCommand cmd = conn.CreateCommand())
{
cmd.CommandText =
@"execute block
as
declare cnt int;
begin
cnt = 999999999;
while (cnt > 0) do
begin
--cnt = cnt-100;
end
end";
IAsyncResult ar = cmd.BeginExecuteNonQuery(null, null);
Thread.Sleep(4000);
Console.WriteLine("Canceling");
cmd.Cancel();
try
{
object result = cmd.EndExecuteNonQuery(ar);
}
catch(FbException ex)
{
Console.WriteLine(ex.Message);
}
and you’ll get the result (even though the loop in fact never ends):
Canceling
operation was cancelled
Of course, you can screw things up by i.e. starting command and then trying to do something else with connection/transaction/command (the ADO.NET providers are not thread safe by default).
Oh, BTW, if you wanna test it, download weekly build.
From time to time I have to run two or more queries that I know will always be two or more – like some first/skip records and also total count. If you write it as two queries and execute, that means two round trips to database. Although it may not matter if the network latency is very small, why not to challenge myself and try to find some workarounds.
Sure you can create some stored procedures and get the data back from these, but I was thinking about more LINQ to Entitiesish way. I recalled a way I one time used inside one project. Although it was done in pure SQL, it, as it turned out, works, kind of, for LINQ to Entities as well.
The idea is using “one row table” and put the queries as columns. Let me demonstrate:
select
(select foo, bar from table1 where ...),
(select baz, foo from table2 where ...)
from OneRowTable;
Where the OneRowTable can be specially created table or i.e. for Firebird RDB$DATABASE or for Oracle Database dual. It isn’t the nicest SQL (and also challenges optimizer), but works. In columns as queries you can put anything you want as long as it is syntactically correct.
OK, what about the Entity Framework or LINQ to Entities respectively. I created the “one row table” first:
create table OneRowTable(x bit primary key);
insert into OneRowTable values (0);
The table needs to have the primary key to be able to import it into entity model, the datatype doesn’t matter (I was using MS SQL, hence the bit).
What about the queries? Similar approach:
var allinone = context.OneRowTable.Select(_ => new
{
AData = context.a.Where(a => a.x.HasValue && a.x.Value > 10).Select(a => new { A1 = a.id, A2 = a.id * 2 }),
BData = context.b.Where(b => b.id < 999).Select(b => new { B1 = b.id, B2 = b.y }),
});
string query = (allinone as ObjectQuery).ToTraceString();
var data = allinone.First();
var adata = data.AData;
var bdata = data.BData;
The a and b are my testing tables. You can check there’s only one query executed. Encapsulating this into some method is only piece of cake.
And how the query looks like? Well for my MS SQL test:
SELECT
[UnionAll1].[x] AS [C1],
[UnionAll1].[C2] AS [C2],
[UnionAll1].[C1] AS [C3],
[UnionAll1].[id] AS [C4],
[UnionAll1].[id1] AS [C5],
[UnionAll1].[C3] AS [C6],
[UnionAll1].[C4] AS [C7],
[UnionAll1].[C5] AS [C8],
[UnionAll1].[C6] AS [C9]
FROM (SELECT
[Project1].[C2] AS [C1],
[Extent1].[x] AS [x],
1 AS [C2],
[Project1].[id] AS [id],
[Project1].[id] AS [id1],
[Project1].[C1] AS [C3],
CAST(NULL AS int) AS [C4],
CAST(NULL AS int) AS [C5],
CAST(NULL AS varchar(1)) AS [C6]
FROM [dbo].[OneRowTable] AS [Extent1]
LEFT OUTER JOIN (SELECT
[Extent2].[id] AS [id],
[Extent2].[id] * 2 AS [C1],
1 AS [C2]
FROM [dbo].[a] AS [Extent2]
WHERE ([Extent2].[x] IS NOT NULL) AND ([Extent2].[x] > 10) ) AS [Project1] ON 1 = 1
UNION ALL
SELECT
2 AS [C1],
[Extent3].[x] AS [x],
[Extent4].[id] AS [id],
CAST(NULL AS int) AS [C2],
CAST(NULL AS int) AS [C3],
CAST(NULL AS int) AS [C4],
[Extent4].[id] AS [id1],
[Extent4].[id] AS [id2],
[Extent4].[y] AS [y]
FROM [dbo].[OneRowTable] AS [Extent3]
CROSS JOIN [dbo].[b] AS [Extent4]
WHERE [Extent4].[id] < 999) AS [UnionAll1]
ORDER BY [UnionAll1].[x] ASC, [UnionAll1].[C1] ASC
Not exactly the original shape. The translator took another way creating two one row results and using union all to get it into one query. Except this, the query is in general the same (the explicit joins are as result same as the subselects, though little bit more confusing in this case).
Again, this isn’t general purpose way of doing it and may result in worse performance than running queries separately and I would recommend using it only after careful testing and on controlled limited set of queries.
During the Friday I realized, that I did a long time nothing with my iPhone & MonoTouch development environment and I should try something more challenging. As I’m still fighting with some good idea for real world test application and my UIs are looking weird, I decided to turn my attention not to iPhone app directly, but to MonoTouch capabilities.
As a true geek I decided to try to connect to Firebird from iPhone. Although, thinking about it, I’m trying to connect to Firebird (or make it work with) with various technologies (Astoria offline, Silverlight, etc.). Because .NET provider for Firebird is pure C# and we have Mono compatible build, I deduced that it should work with iPhone too.
Sure, it’s a nice challenge to whole MonoTouch stack, because the .NET provider is more about the code than about the application itself. And we’re using there a lot of different things that can go wrong or may not be available or compilable to native code. And I have to say, the guys behind MonoTouch did a great work (I still can’t believe it).
With couple of minor tweaks I was able to create application that connects from iPhone (simulator) through internet to Firebird server. Pure C#, no hacking or major problems.
Application connecting to Firebird server and showing the server version.
First I’m impressed how mature the MonoTouch is. Second I’m still trying think thru all the possibilities you have with this. With some work on UI you can deliver the same database oriented application to Windows Mobile and iPhone using the same business layer (sure some webservice approach would be better, but …).
Looks like it’s time to stop playing and get some serious test app done.
I’m wondering whether we should start providing build of .NET provider for Firebird for MonoTouch/iPhone, as we have for Compact Framework?
Společně s Databázovým světem tu máme další Firebird školení. Více informací, včetně možnosti přihlášení na: http://www.dbsvet.cz/view.php?cisloclanku=2010012101.
Starter for (but not only) morning:
Holger Klemt:
Stefan Heymann doing the same as me:
Dmitry Yemanov:
Vlad Khorsun:
Roman Rokytskyy:
In between sessions:
During session:
In between sessions:
Everybody is solving problems during conference:
Talking about (not only) Firebird in hallways:
The conference is about to start. I’ll write here more and more from it, read it top to bottom.
- It’s 8:25, conference rooms are getting the last polish. You can also deduct, that I successfully found the place.
- The conference is held in Bauzentrum in München. There’s a lot of stuff for people who are building houses etc. in hallways. I like it.
- Session from Dmitry. Good for people asking about limitations and features, why are/aren’t there. The final statement is that Firebird Project isn’t trying to implement all features from Oracle, MS SQL Server, PostgreSQL, … But project is definitely open to good ideas from other projects. And no experiments with features.
- The trace and audit session from Vlad just finished. I like this new feature, but I was not paying attention to during development, so this was a nice summary of my shattered knowledge. But what I don’t like is the configuration file format – mix of XML and standard text config file.
And same for output, it’s not some kind of “computer ready” format, like i.e. again XML, it’s just a text, which will be for people harder to parse – but Thomas Steinmaurer already created one application. However the API is open, so probably sooner or later, I hope, somebody will create plugin with this output (and maybe also one for putting the content into database – what about MS SQL and using Analysis Services? 
)
- After these sessions it was Holger’s turn. About the replication of databases. It was interesting to see the different approach based on creating the actual query executed from inside the trigger. Sure it has some limitations and we found some also during the session, but if you’re OK with the way how it works, it’s a good and easy-to-implement solution. But I think, just because I rather wanna to have more “based on values rather than on creating commands” approach to the synchronization/replication I would probably go in a different direction.
- After this session was my session – the PocketPC and Firebird stuff. It was, sure, the best topic of the day , and because describing own presentation is weird, I would just skip it and hand you to the recording which will be available, for sure.
- The final session was a all-hands-session about the Firebird and performance. There’s nothing special to write about it, because everybody put his/her input it was better to be there than not.
- And maybe the most important part was the city sightseeing and dinner during the evening. These “after-events” are great opprotunity to ask anybody you choose about your problem or give an interesting feedback, hence if you’re not here, you’re definitely missing something.
Day 2 is ready. Everybody fresh and relaxed . Weather in München is nice.
- The first session today was from Vlad about mainly some MS C++ runtime issues with recent changes in WinXP, Vista and Win7. If you were deploying the server in the meantime (or you’re using older (sub)versions) it was definitely worth listening. The current versions of Firebird server have not these issues, because it was successfully solved.
- Following session was from Alex about new protocol features, mainly in 2.5. As a provider writer I was a nice overview of what I will need to do in next couple of months to catch up with server. Also if you wanna to use some brand new features, this session was a good opportunity to see what’s going on inside and what you can do (i.e. if you components are not supporting all options).
- If you’re reading this, you missed my presentation, which was the next in schedule. Again I’ll skip any description.
- Session finished right now was Holger’s about backup and restore. Because I saw last presentation from Ivan Prenosil last year about (I think) 10 ways of doing backup I was not expecting something new. But in fact there was something new. The IBExpert except the IBExpert itself has a really nice set of tools, like a scheduler for backup & restore which you can very easily plug into your environment and use it for almost hot backup of your database on different server. Similarly for dealing with metadata changes and pumping data out and in.
- The final session from regular speaker was Dmitry’s about the lock manager. To be honest I was never paying to much attention to fb_lock_print utility and I had only a very limited knowledge about it. But this presentation, especially demos, widened my knowledge little bit and I know, at least, what useful information I can find there, and if I’ll not forgot all stuff also how to use these. And seeing what’s going on inside the lock manager also helps understanding the internals.
- Really the last session of the day was continuation of talking about improving performance of Firebird (itself or tools) and sharing and exchanging the information. Because everybody was contributing with (but mainly Holger) own pieces, it was really great ending of the day.
And here we’re. The last day of conference. Everybody is looking little bit exhausted, but I’m sure we all are gonna to survive no matter what.
- First session of the day, was classical session about “what we can expect in next development and in next year”, held by Dmitry. It was a nice overview what’s going to happen and if you’re not a member of devel and/or architect list (or you’re not reading it often) also nice summary.
- Then the Vlad came in with new SQL features in Firebird 2.5. As I like a 2.5 a lot and I’m using it for more than a year, I was more or less familiar with these features (although I’m using only few of these). So if you’re too lazy to read release notes for betas and RCs, this session was surely good for you.
- Before the lunch Alex had session about security. I liked the small recap of the history of security in Firebird and InterBase. Then the walk thru the new features and improvements was really good and exhausting, nice samples. I’m really looking forward to Firebird 3.0 to test all new security, mainly authentication functions. This could also make life easier for i.e. hosting providers offering Firebird.
- Once again (and for last this year) skipping my session. (BTW I realized that even if you’re reading this text, there’s change, that you’ve seen my presentation, so my yesterdays statement wasn’t completely correct.)
- The session about the BI tools and Firebird from Roman was really nice. My focus is mainly in OLTP, and I’m looking to OLAP world only little bit, and this was a really nice for me to see also the other side of some problems and see, for me unknown, tools and what is and what is not possible and how hard or easy (desining some transformation looked really easy and quick, at a first sigh).
- Following session was from Roman too. Simply about the Java driver and using it. It was really nice to see how it works in Java world and what problems they’re facing and comparing these in my head with .NET world problems. The example of Hibernate was nice too, as it’s a similar tool to Entity Framework and “father” of nHibernate, so I was able to briefly look to different approach for O/M mappers solution.
- The final (of the day) + final (of the conference) session was simply roundtable, where every developer from different parts of Firebird project (core, .NET, Java, …) introduced little bit the subproject he is working on as well as him/herself. I was expecting people asking little bit too much about these subprojects and maybe sharing ideas and needs, but the discussion didn’t furiously started. A pity.
What to say about this years conference? It was good definitely. I was really enjoying my presence as well as my presentations. So see you next year, maybe face to face maybe reading this feed (if I’ll be doing it).
Společně s Databázovým světem tu máme další Firebird školení. Více informací, včetně možnosti přihlášení na: http://www.dbsvet.cz/view.php?cisloclanku=2009110403.
Next Firebird conference is coming. This year in München, Germany. I’ve never been in München though it’s pretty close to Czech Rep. thus I’m looking forward.
You can find info about conference at firebird-conference.com. I’ll be speaking there too, hence if you’re interested in Firebird and .NET you should definitely come. Every day I have one session. I’ll be covering new (2.5+) protocol implementation in .NET client for Firebird 2.1, Entity Framework support (also new in 2.5) and finally you’ll see how to create Windows phone (formely PocketPC, …) application and accessing Firebird database.
And the conference will be also great place to meet people you know from list etc. and talk face to face about your Firebird related problems, challenges and solutions. If you have any specific need to show (related to my three sessions) feel free to drop line in comments.
I had this idea on my list for a couple of months and I was always postponing it, because it’s stupid. But you know. Exploring the unexplored ways, that’s what I like to do .
But during (or after, I don’t remember) my presentation about Entity Framework there was a question about accessing the data provided by EF from Silverlight. Sure, doing it directly isn’t a good idea and in fact this is the reason why Astoria, eh, ADO.NET Data Services is here. But is this really stupid? Can it work?
Nope. Not at all. I tried to build FirebirdClient in a Silverlight environment and I failed. I expected to fail after some attempts with modifications and using only subset of features like i.e for Compact Framework, but this was really fast. Silverlight is only subset of .NET Framework. And one crucial part is not there, it’s System.Data stuff and without it you can drop major part of any ADO.NET provider’s code.
If you need data, use ADO.NET Data Services or any other webservices (which will also fit for DDL etc. commands). That also means, that writing Silverlight based Firebird database manager (without any support backend), which is one of few reasonable ideas, cannot be done either.
Možná jste si všimli, že jste si nevšimli žádné upoutávky na letošní Firebird Developers‘ Day. Není to chyba na vašem přijímači. Zatím žádné takové oznámení nebylo.
Popravdě, letos to s Firebird Developers‘ Day vypadá špatně. Ačkoli stále tvrdím, že “krize” je do jisté úrovně vyšroubovaná médii, asi zde v druhotné úrovni zasáhla. Jak jistě víte, Firebird Developers‘ Day je konference, která je zdarma, proto veškeré náklady musíme pokrýt ze sponzorských darů. Bohužel letos, jedna z hlavních úlev, kterou jsme měli – sál Věž na pražském Albertově není letos dostupný. A náklady na libovolné komerční prezentační místo jsou pro Firebird Developers‘ Day astronomické.
Zatím se nevzdáváme, je možné, že se něco podaří najít. Nicméně stále více začínáme uvažovat o přesunutí Firebird Developers‘ Day na jarní termín a výběr malého vstupného, které by pomohlo problémy s náklady vyřešit. Osobně si myslím, že konference je skvělou možností setkat se s lidmi z oboru a vyslechnout si (doufejme) zajímavá témata z různých koutů Firebirdu a proto by nemuselo být např. 200 korun dramatických pro návštěvníka a přitom by rapidně pomohlo konferenci.
Není to dobrá zpráva, ale nic není ztraceno. Tak jako tak, rád bych slyšel vaše názory na zavedení rozumného vstupného. Je to nepřekonatelný problém?
Firebird doesn’t have identity/autoincrement columns like i.e. MS SQL or MySQL. Firebird has concept of generators/sequences (as know i.e. in Oracle). This is more powerful concept, but comes also with drawbacks, because you can say for sure, whether the column values is generated or not. This is causing problems, if you set StoreGeneratedPattern in your model manually and then updated model from database – it’s lost. Because this can be big pain in the ass, FirebirdClient can now report the column as “Identity” if you give it little help.
If you put into comment of column #PK_GEN#, then FirebirdClient will report it as generated primary key, resulting in StoreGeneratedPattern to be set to “Identity”. Hence you don’t have to every time manually change the model and easily use automatic fetching of the value from database when saving changes. If you wanna test it, grab build from weekly builds.
I have a strong feeling that MS SQL knows I don’t like it. I don’t say it’s a bad database, but sometimes it’s really “interesting”.
OK, so what I faced this time? Let’s start with basic facts. The NULL value in database is a special value. NULL and NULL is again NULL, NULL and False is again NULL and NULL isn’t equal to NULL. Two days ago I was creating a chain of records in database (which isn’t too relationalish, but …) and I needed unique constraint on one column. No problem you may think. So did I. But not in MS SQL.
Check this example:
1> create table test(id int primary key, foo int);
2> create unique index idx_text on test(foo);
3> go
1> insert into test values (1, null);
2> go
(1 rows affected)
1> insert into test values (2, null);
2> go
Msg 2601, Level 14, State 1, Server X2-001SQLEXPRESS, Line 1 Cannot insert duplicate key row in object 'dbo.test' with unique index 'idx_text '.
The statement has been terminated.
What a mess! Looks like somebody in MS SQL engine team thinks NULL == NULL. After some railing, testing on Firebird and asking my friend about Oracle, I googled: https://connect.microsoft.com/SQLServer/feedback/ViewFeedback.aspx?FeedbackID=299229. Looks like I’m not alone; feeling better.
Luckily I’m working on MS SQL 2008 and I can use filtered indices. Created unique index with where clause where <column> is not null and I’m done. But boy that was a bitter finding. Hope I’ll not be punched to the face with these basics again in an at least two months.
Wondering what changed on Earth in last, say, four weeks. I’m getting more than average (read: more than zero) emails, asking whether FirebirdClient works with InterBase. Similarly in mailing list.
Well, the short answer is no. The long: FirebirdClient is created as part of Firebird project. Hence it’s focused on Firebird. And even both Firebird and InterBase have same history, now the engines, and more in future, are more and more different. So it may work (with some tweaks) with current versions of InterBase, but it’s tested with (sponsored by, focused on) Firebird only.
I finally got my hands on the new feature in EF4, Code Only. It’s now available in feature CTP. What’s the code only? Very shortly you write just a code and express your mapping in code as well. There’s no model, no edmx file, no CSDL, MSL, SSDL files.
The current version is pretty limited, it’s more preview than something you can do some work with (which I wasn’t aware of and I was little disappointed). You can read more about what will be available on http://blogs.msdn.com/efdesign/archive/2009/06/10/code-only.aspx, http://blogs.msdn.com/efdesign/archive/2009/08/03/code-only-enhancements.aspx and http://thedatafarm.com/blog/data-access/next-version-of-ef-code-only-design-laid-out-by-ms/.
I mainly wanted to try it on a non standard (read: not “follow this demo”) MS SQL database and on Firebird as well. The first bad news is, that current CTP supports only SqlClient. And probably some following previews will too, as the other providers model will be built on top of it (but I’ll try to push this as much as I can, to see some Firebird demo soon). The other is, that the currently available version is limited, even features in first Code Only blog post are not working. Right now you can only create a context and use it for work with all defaults – default names for tables, default mapping etc.
using (SqlConnection conn = new SqlConnection(@"Data Source=.sqlexpress;Initial Catalog=testovaci;Integrated Security=True;Pooling=False"))
{
ContextBuilder<COContext> builder = new ContextBuilder<COContext>();
COContext context = builder.Create(conn);
string script = context.CreateDatabaseScript();
context.Masters.ToArray();
}
Nothing special. If you try it with FirebirdClient, you’ll get NotSupportedException immediately. Dammit.
using (FbConnection conn = new FbConnection("database=localhost:rrr.fdb;user=sysdba;password=sysdba"))
{
ContextBuilder<COContext> builder = new ContextBuilder<COContext>();
builder.Create(conn);
}
Despite the frustration I found couple of new interesting extension methods (in Microsoft.Data.Objects, also ContextBuilder sits there). One of these is CreateDatabaseScript. This method works not only with Code Only created ObjectContext, but on every ObjectContext. So you can create your database creation script during runtime even if you’re using i.e. EDMX file easily. I’m also seeing great opportunity for this with Code Only setup during runtime. You can have different builds with different setups and create script for users based on selection. And by the way, there’s also CreateDatabase method available. But again right now works only with MS SQL only. But I know other databases will be supported as well, I have tested some pieces already.
I like the Code Only feature, maybe more than Model First (probably because I’m using ERD tools to model my databases). And I’m looking forward to see more progress on it, and also the model for 3rd party providers.
I’m proud to announce next version of FirebirdClient – 2.5.1. This release is focused mainly on bug fixes, no new features were added.
You can see all fixed issues from tracker. And download it from http://firebirdsql.org/index.php?op=files&id=netprovider.
Thanks to all people who reported any issues for trying to make FirebirdClient better.
