Are there any PHP based CMS which could be integrated with an existing database? My client already has a big inventory solution which was written in VBA. Now we need to setup a web based shop for them and we are thinking of setting up a CMS from the shelf.
Is there any way we can integrate the current database scheme with that of CMS ?
That depends entirely on what the big inventory solution does, where it is running, how it is structured, and how the two solutions are supposed to coexist.
Usually though, you will want to make use of existing export/import functions on both sides (e.g. XML) instead of having two applications meddle with the same data base. That often ends in tears.