My goal would be to write an accumulation of many webapplications, like google services (mail, calendar, paperwork, ...).

It will likely be designed in PHP with Zend Framework (Version 5). I personally use MySQL to keep data.

The service collection ought to always be extension (new releases) easy.

Could it be helpful use a own database for each service? They'd have couple of tables only (pretty much 3). That indicates I must use Zend's multiple database adapter.

Another solution is by using one large database for that hole collection. The benefits are will be able to use foreign secrets between your tables of various programs. I additionally can use the default database adapter.

All of the programs are enmashed with one another close.

What will work better?

For those who have enough databases out of your provider you could utilize multiple databases, but when you've User accounts its easier to create one primary-Database for your.

Break the help by helping cover their one database each, such as the service that identifies the customers. All the services should speak with one another via web services. This architecture would be the most flexible when it comes to scaling pieces individually in addition to maintaining the pieces individually.

It's impossible to provide something more specific when it comes to architecture of these a credit card applicatoin ecosystem without substantially more details concerning the project, and incidentally, that might be past the scope of the site to reply to.