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

[Martin Kutschker]

Am 10.10.2010 10:05, schrieb Michael Feher:
> 
> It's not about bypassing the persistence API of FLOW3 but about a possibility to exchange data with
> foreign applications on the DBs level.

I would in this case neither try to write into the DB of the CR nor that of any persistence layer
built on a DB.

> 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.

In this case you don't need the CR (unless you want to import the data) nor the persistence layer
(measurements are values not entities). What you want is perhaps a DB abstraction layer (in case you
do not to access the DB directly).

> 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.

Aha!

> 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.

You mean an implementation of Table/Row Data Gateway or Active Record?

Masi