Stephan Goeldi writes:

Let's assume I have two databases. An external connected SQL database and the ZODB. In the external DB I have a table with two columns: 'name' and 'email'. In the ZODB I have a table with the columns 'name' and 'place'. How can I extract data from both in one turn using the foreign key 'name'? e.g. I want this result:

name - email - place

Is this possible? This depends on what you mean with "in one turn":

In general, there is no join operation defined between relational databases and the ZODB. You need to implement is yourself. But, it is not difficult (in your special case). Dieter