BETTER Download Firebird Database
Lauro Beriault
Firebird is an open-source SQL relational database management system that supports Linux, Microsoft Windows, macOS and other Unix platforms.[2] The database forked from Borland's open source edition of InterBase in 2000 but the code has been largely rewritten since Firebird 1.5.[3]
This decision caused concern within the Firebird database project due to the assumption that users and Internet search engines would be confused by a database and a web browser both using the name Firebird.[20][21] The Mozilla developers issued a statement,[22] making clear that their software package was called "Mozilla Firebird", not "Firebird".[23][24] The statement also said that the Mozilla Firebird name was a project codename.
Firebird inherited the storage architecture of Interbase. To ensure the ACID properties of transactions, the database engine keeps different versions of each record changed by the active users in the database. When the transactions are committed, the last version of every changed record is marked as the definitive. If transactions are rolled back, the database engine keeps the mark on the original record versions, leaving them untouched.[32] As a result, Firebird disk writes are very reduced compared to databases that use the traditional transaction log architecture.[33] Writing transactions does not prevent reading and vice versa, because each one sees its own version of the database.[34] The tradeoff is that some maintenance ("sweeping") is required from time to time to clean up old record versions and free disk space.[35]
Firebird makes all indices of the database behave like well-tuned "clustered indexes" used by other architectures. Firebird index buckets aren't subject to two-phase locking, and boolean "and" and "or" operations can be performed on intermediate bitmaps at a negligible cost, eliminating the need for the optimizer to choose between alternative indexes.[37]
The Firebird database engine and its modules are released under an open-source license, the Initial Developer's Public License (IDPL), a variant of the Mozilla Public License (MPL) version 1.1. It does not require the developer to open the products using Firebird or even custom-derivatives made from its source code, but if the developer chooses to do so, then some terms and conditions should be honored. The IDPL allows the developer to make proprietary, closed-source applications that use Firebird or are based on it.[38]
The Firebird native API is used directly or indirectly by applications or middleware that connect to a Firebird database. It is implemented in the client library, fbclient.dll, on Windows systems, and in libfbclient.so on Unix ones.[39]
I am relatively new to database programming. I use firebird 2.5 with IBPP. I have at least two applications using the sampe firebird database. I want to connect with the embedded variant (fbembedded.dll, icudt30.dll, icuc30.dll), since it will be a host application on customer PCs. I wrote a simple test application reading data from the database and started this application three times at the same time. Everything worked.
But now I am not shure if this works always and if this works stable without the danger to corrupt data. Because when I have a connection with the database with the viewer ibexpert my test application cannot connect to the database. Additionally, the documantation sais (firebirdEmbedded):
You can have multiple embedded servers running at the same time, and you can have multiple apps connecting to the same embedded server. Having a regular server already running isn't a problem either. However, an embedded server locks a database file for its own exclusive use after successful connection. This means that you cannot access the same database from multiple embedded server processes simultaneously (or from any other servers, once an embedded server has locked the file).
The document you refer to is based on Firebird 2.0 or 2.1. The 'server' architecture of Firebird Embedded on Windows was changed in Firebird 2.5. Before Firebird 2.5, Firebird Embedded on Windows behaved as SuperServer, meaning it required exclusive access to the database file.
Starting with Firebird 2.5, Firebird Embedded on Windows behaves like the SuperClassic server model, which means it uses shared access to the database files, and that the same database can be accessed by multiple Firebird Embedded applications and Firebird servers in the Classic or SuperClassic server model (but not SuperServer) if they are running on the same machine. The downside of this change is that embedded applications need to be able to create, read and write the shared database lockfiles (in C:\ProgramData\Firebird).
The embedded server in the Windows library, fbembed.dll, now uses Superclassic, not Superserver as previously, thus unifying its model with that of local connection to Superclassic on POSIX. The database file-lock that previously restricted connections to a single application space is replaced by a global lock table that allows simultaneous access to the same database from different embedded server modules. This facilitates concurrent debugging of applications and use of native utility tools like gbak, gstat and so on.
For posterity, I found that I was getting 'Dynamic SQL error -104. Unexpected end of command" when trying to connect. And I needed to change the default validation query in the driver settings from 'SELECT 1' to 'SELECT * FROM RDB$RELATIONS' to establish a connection. I got that query from this page: Working with databases
I know that using Firebird 2.5+ I can check if there are users accessing my database using SQL, but unfortunately, Firebird 2.0 doesn't have this feature. Yes, I know it's an old version, but it's a legacy software and I'm not allowed to upgrade this in a short time... :(
-at[tach] : this parameter prevents any new connections to the database from being made with the exception of the SYSDBA and the database owner. The shutdown will fail if there are any sessions connected after the timeout period has expired. It makes no difference if those connected sessions belong to the SYSDBA, the database owner or any other user. Any connections remaining will terminate the shutdown with the following details:
There is also Services API to do it so your database access library should expose the shutdown function. Specify a short shutdown, and if it failed - then there were some users. If it succeeded - now you can go on with maintenance, having a warranty client applications will not be able to connect.
Then on disconnect trigger might be checking whether all "main workflow" apps disconnected and POST_EVENT to notify servicing utilities. However those utilities would still have to shutdown the database first, anyway.
Hi MatStich,
when the DB Connector is green it was able to create a connection to the database. So this is already a good start. However it seems that KNIME can not get the meta data from the driver to list the available schemata. The driver should support JDBC version 4.1 or later which the Firebird Database driver does not seem to support.
You might still be able to work with the database. Have you tried to enter the schema and table name manually in the DB Table Selector node? If this also fails it might be that Firebird does not support sub-queries which then will limit the nodes that you can use since most of the DB nodes use sub-queries. If this is the case you can still use the DB Query Reader node to read data from the DB.
Bye
Tobias
Hi Matthias,
thanks for the info. I was able to reproduce the problem. It looks like that Firebird does not return any schema which the new framework expects as of now. We will be looking into it to change this and also support databases that do not support schemas when listing the metadata. If everything works out this will be fixed with the release in summer.
Bye
Tobias
Hey i wanted to connect to my local firebird database, but when i log in with my user and password i get this error with xnet. And ich dont know where this xnet is coming from because i put the localhost ip to the connecting.
NOTE: it should be clarified that for the connection to be made from hedisql for the firebird 2.5.x version, libray must be used: "fbcliente-2.x.dll" since with the one that comes predetermined in heisql, it was impossible to connect.This version can be found from the official firebird page by specifically downloading the firebird 2.5.x version then you pass the fbcliente.dll to the heisql folder so that it can be selected.
I'm trying to use HeidiSQL with Firebird for the first time and I'm having a problem. The Firebird version is 2.5.x installed on an Ubuntu Server 20.04.4 (terminal only). I put the appropriate dll in the HeidiSQL folder (C:\Program Files\HeidiSQL) but when trying to open the session the error window appears with the following message; connection failure; SQL error (0). See attached screenshot.This same database is working and being accessed with the same settings (ip, login, password, path,...) by a Delphi program using Unidac.
It has been difficult for me to put in time on my own military simulation development in the past several months due to another project I am currently developing. In this project, I am currently converting the database from SQL Server LocalDB to the Firebird Embedded Edition.
However, for experienced professionals and hobbyists who have worked with other database engines such as SQL Server, Oracle, MySQL, and PostgreSQL, coming to Firebird can be a shock to the system as a result of its own way of doing things.
To make things easier for anyone who wants to try out Firebird for their own projects, I have written a long piece on the many idiosyncrasies\inconsistencies with this database engine that are found between using a database manager and the ADO.NET provider.
The Firebird Database Browser included in RazorSQL allows users to browse database objects and structures. The main RazorSQL window consists of three mainparts. The Firebird database browser is on the left-hand side of the screen. TheFirebird SQL editor and query execution window is on the upper part of the right-sideof the screen, and the Firebird query results section is below the SQL editor.
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