Firedac and simultaneous connection to different version of Firebird

[Jacek Laskowski 57]

Is it possible to connect to two versions of the Firebird server (2.5 and 3) at the same time using Firedac?

Both connections should use a different version of fbclient.dll, how to do it?

[Remy Lebeau 1396]

56 minutes ago, Jacek Laskowski said:

Is it possible to connect to two versions of the Firebird server (2.5 and 3) at the same time using Firedac?

Both connections should use a different version of fbclient.dll, how to do it?

I don't know how FireDAC works internally, or how it loads fbclient.dll, but have a look at Activation Contexts, which allow a process to load multiple versions of a DLL at the same time.  Create a context for one DLL and connect to Firebird while that context is active, then create another context for the other DLL and connect to Firebird again.  Not sure if it will work in your situation, but it is worth a try.

[Guest]

1 hour ago, Jacek Laskowski said:

Both connections should use a different version of fbclient.dll, how to do it?

I do not use FireDAC but generally, you should be able to access a 2.5 DB using a 3.0 fbclient.dll.

What may give you headaches is if FireDAC when it build SQLs (supporitng cursors) uses 3.0 syntax for your 2.5 DB. Most should work anyway, IMHO.

[Markus Kinzler 174]

Quote

you should be able to access a 2.5 DB using a 3.0 fbclient.dll.

No, older ODS aren't supported for now.

[Jacek Laskowski 57]

I tried to use the library from version 3 and for now it seems to work also for connections to the 2.5 server. But I have not written anything to the base yet, only readings.
But is it safe and stable?

[Guest]

18 hours ago, Markus Kinzler said:

No, older ODS aren't supported for now.

Marcus, i mean accessing a 2.5 install (on a server, not locally) using a client install with the fbclient.dll from 3.0. Really?

ODS = On Disk Structure, a very server-side concept.

Opening a FB 3 file using a 2.5 server - that won't work because of different ODS. 

[Markus Kinzler 174]

Quote

Marcus, i mean accessing a 2.5 install (on a server, not locally) using a client install with the fbclient.dll from 3.0. Really?

This should work.

[Jacek Laskowski 57]

I answer my question. Yes, it is possible to simultaneously connect to several versions of the same server.

Here's the solution:

 

http://docwiki.embarcadero.com/Libraries/Tokyo/en/FireDAC.Phys.TFDPhysDriverLink.DriverID

[Dmitry Arefiev 101]

More to read:

http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Configuring_Drivers_(FireDAC)