[FLOW3-general] CR support for simultaneous access to multiple databases

[Michael Feher]

>> As FLOW3 claims to be a framework not only designed for TYPO3 I think it
>> is necessary to be able to exchange data with other applications on a DB
>> level.
>
> Why do you want to use the real DB access if there is a good API for it?
> IMO the goal is to have a perfect api

It's not about bypassing the persistence API of FLOW3 but about a 
possibility to exchange data with foreign applications on the DBs level.

Let's discuss this with a simple example.

Assume you have a SCADA System which is connected to several thousand 
measurement devices (temperature, flow speed, distance, whatever ) and 
writes the measurement data into a database. The structure of the 
database is well documented and each record in the database represents a 
single instance of a measurement. You now want to write an web 
application which displays this data.

So what you need is some kind of data exchange between the 2 
applications (SCADA and FLOW3). The simplest and mostly used approach is 
that one application directly accesses the database of the other 
application.

So this would required that either the SCADA system writes into the 
FLOW3 database (this is something which you definitely don't want) or 
the FLOW3 application connects to the SCADA database. Currently you can 
only connect yourself to the external database and and do all the SQL 
stuff within the FLOW3 application.

What you would like to do is to build a PHP class which represents the 
Measurement (containing properties for each column in the table of the 
external database) and tell FLOW3 to connect to the foreign database and 
fetch the data for you. So that you do not have to bother about the SQL 
stuff.