Are there major disadvantages using the embedded Firebird 3 in a multi-user application server (Delphi Webbroker) instead of the full blown server install?
The application usually has very short transactions with low data volume.
As far as I am informed accessing one database file with multiple threads through the embedded server is not problematic but user security is not available. As the application server does the rights stuff I do not need Firebird security.
But will I loose performance or things like garbage collection?
Firebird Embedded provides all the features (except network access and authentication) that a normal Firebird server provides. However, because it is in-process, any problems that cause your application to crash, will take Firebird with it and vice versa.
Other possible downsides:
Garbage collection will - as far as I know - always use the 'cooperative' model (where the connection to find old record versions, is the one that cleans it up),
You can't use other tools to access your database remotely which may make administration harder,
You can't put your database on a separate server from your web application (think of security requirements).
Personally, I would only choose Firebird Embedded if the situation calls for it. In all other situations, I will use Firebird Server.
unfortunately i have to work with ancient piece of software, that uses paradox tables.
The following code gives me exception:
fdcMainPX->TxOptions->AutoCommit=false;
fdcMainPX->StartTransaction(); <---
"Project xxx raised exception class EFDException with message '[FireDAC][Phys][ODBC]-303. Capability is not supported'"
It appears, that windows odbc driver for paradox doesn't support transactions. I suppose that ole jet engine allows transactions with paradox but i'd rather use Firedac over ADO or BDE.
How to set up connection with firedac to use MS Ole db ?
Maybe there is another way?
I am using C++ Builder XE6 Pro with Firedac
Paradox DBMS doesn't seem to be capable of transactions at all (maybe its new version, part of the Corel product is, but that doesn't seem to be your case).
However, if you just want to keep consistency of certain data batches in a single connection session, you can use cached updates.
I have an application in my company. I want to convert it from BDE to ADO Connection.
I searched almost everywhere, I did not find any good answer.
The AIM IS
Convert that BDE connection to ADO connection but we need to use TQuery component to fetch data from database.
So, it will look like we are using BDE but internally it uses ADO Connection.
So, please answer this question you cant imagine, how thankful i will be.
... if somehow we can set the database Alias to ADO connection ...
Just take a look at the source code of Delphi's BDE and ADO support (in e.g. DBTables.Pas and ADOInt.Pas + ADODB.Pas and you will soon see that they are as different as chalk and cheese.
You have no hope of e.g. using a TAdoConnection via the BDE from a Delphi app.
What you could do is do move your data to an ADO database (e.g. MS Sql Server) and then create a) a System DSN to connect to the ADO db via ODBC and then b) set up a BDE Alias that uses the BDE alias and c) change your existing BDE app to use the new alias instead of the one it currently uses. That way, you can continue using your existing app to access the ADO version of the data via TTable, TQuery etc and develop a parallel TAdo-component based equivalent at your leisure.
You could easily try this out using the traditional Delphi MastApp or "Fish Facts" demo application and data. Getting your existing BDE app to access an ADO-compatible copy of your data via an ODBC alias should not be more than a day's work even if you have never done it before. Actually converting your BDE app to ADO would likely take rather longer, though.
There are countless examples of different ways of copying BDE (e.g. Paradox) data to ADO data on the internet. Try looking at a few.
Has somebody real experience with firebird databases over the internet?
I have a typical windows accounting/ERP software (done with delphi) that works with the firebird database server pretty well.. Now my users (300 aprox. now, but should increment) also want to work "in the cloud" (connecting from the office, from the laptop, from the house, etc.). It is a lot of work of recreating everything to a standard web application (let's say for example, HTML+CSS+JS+PHP+MYSQL), so I'm considering keeping the win client (I don't care about other OSes) but instead of the server living in the clients LANs moving it to a pair of dedicated servers that I will contract (one primary and one secondary againts failures for starting).
Searching I've come across this faq http://www.firebirdfaq.org/faq53/ that explains that the fb protocol it isn't ideal for working in the internet, but still all my users today have at least a 1MBbit/sec ADSL internet connection (I don't think that to be slow as the faq denotes).
Somebody have done this? what was the experience? how secure are fb servers for being open to the internet? how well they scale?
I know that building a "middleware" with SOAP for example will be more normal, but still the solution I'm evaluating here is much more fast and easy (still I have some work with the replication, backup, hearbreath services, but it's much less than redoing everything for the web).
Thanks! Edit: FB version: 2.5.
I had being trying to "push" the Firebird Core developers to improve the Firebird protocol to get better speed with high latency network (aka. Internet). Recently, Dmitry Yemanov published some articles in his blog about this subject (dyemanov.blogspot.com). It seems that there is margin for optimizations, and I would really like to see this coming in FB 2.5.3 and FB 3.0, although there is no warranty for this happening in those versions or anytime soon. You can vote in such improvement here: http://tracker.firebirdsql.org/browse/CORE-2530
Safety? You may try to set up a VPN. It also may help with speed, since most of the VPNs software out there (Zebedee, etc) can compress the data being transfered, helping to speed up data transfer in some cases.
Some of my customers do use Firebird traditional C/S over the internet. It is much slower compared to local network, and of course, how much slower depends basically on the link speed and latency. You can do some optimization at the client side too, using metadata cache, etc. but don't expect miracles with the currently protocol. I would say that for whole day working, using Terminal Services would be a better option for now.
The response about the scaling question
Firebird runs in production on large big iron servers : 512G of ram 100.000 concurrent users
We run Firebird to power larger systems (for 12 government agencies
and 3 banks). It has approximately 100000 end users multiplexed
through 2500 (max) pooled connections
https://plus.google.com/111558763769231855886/posts/Q1ACy1yyTgP
The protocol in Firebird 2.5 is improoved there is still room left for 3.0 but you can check
what is already done
http://asfernandes.blogspot.com/2009/07/network-latency-influence-on-firebird.html
And the future enhancements in 3.0
http://www.firebirdnews.org/?p=6953
To protect your connection i guess the best bet is ssl/ssh tunnel (it can be a opnvpn)
with high compression option
http://mapopa.blogspot.com/2010/11/securing-firebird-using-ssh-tunnel.html
FB protocol problem isn't about bandwidth, but latency. In my experience, some operations can be very slow over internet/VPN compared to LAN or local connection. I haven't examined issue further since I don't really run applications over internet connection.
However, I suggest three-tier model for application. Create own application server, which runs on database server/same network. Let the clients talk with application server and you get maximum performance.
There are some N-tier application/middleware frameworks for Delphi:
RemObjects SDK and DataAbstract
RealThinClient
kbmMW
Delphi's own DataSnap
MidWare
With those you can get data compression, encryption, binary messages (faster than SOAP) etc.
You can implement TCP/IP packets encryption/decryption directly in the firebird engine itself.
Personnaly, i have downloaded the Firebird 2.5 source code and injected secure tunnelization code directly in his low level communication layer (the INET socket layer). Now, encryption/decryption is done directly by the firebird engine for each TCP/IP packet both at the server side and the client side (fbclient.dll).
Then there is no need to re-structure the client application except adding one line of code that provide the secret key you choose to crypt communication to the fbclient.dll. The same secret key must be declared in the firebird.conf file of your server installation.
I have also implemented a proxy negociation solution in the fbclient.dll in order to allow to TCP/IP packets to pass throught any proxy server (like Microsoft ISA Server for example).
For us, this architecture is functional for more than one year in a real production system.
kbmMW CodeGear Edition is free but without source. It can be used for commercial apps.
Download it after registering at: https://portal.components4developers.com
In case you see certificate errors (you shouldnt but I know we have heard that some actually do), accept and ignore them. The site is valid despite the cert.error.
kbmMW CodeGear Edition contains a subset of kbmMW Professional Edition, but supports the following Delphi database API's:
Borland Database Engine
DBExpress
kbmMemTable
SQLite3
It supports binary, binary over HTML, XML and SOAP protocols in communication with clients.
It contains everything you need incl.
unified remote custom method invocation
unified remote dataset query, execute and data change resolving
unified database meta data handling and creation (tables, fields, indexes, generators/sequencers)
optional automatic proxying of requests to another server and proxying results back to original requester
full native XML DOM and SAX support
full dataset briefcase support as CSV, or binary data
advanced but simple to use wizard for creating new application server services
THere is one caveat though. Newest version of kbmMW CodeGear Edition always only supports newest Delphi version. You can still download older kbmMW CodeGear Editions matching older Delphi releases.
kbMMW Professional Edition and kbmMW Enterprise Edition do not have such limitations, and currently supports D7, D2006, D2007, D2010, DXE, DXE2 along with Embarcadero C++ counterparts.
best regards
Kim Madsen
www.components4developers.com
I want to develop windows service in Delphi that communicates with an Oracle server via ADO.
Which guidelines should I follow?
I already know ADO, but I don't have experience with the windows services.
Thanks in advance.
I think Tutorial for making a Service Application using Delphi is good point to start.
And If you want to connect database in an service app. you can create second thread in OnStart event of TService class.
As a hint: I did have lot's of problems when developing a service using ADO to an Oracle server. After some testing the problem lied in the fact that the ADO driver from Oracle was unable to handle concurrent connections in multiple threads. In the end we used a single thread to do all ADO connections and sync the resulting datasets to the threads that did the processing.