Hello everyone,
I've just joined the forums after some pointers, but not sure where to post my question.

I'll try and briefly outline it below, so if you can point me to the right section of the forum I'll post the full question there

(On behalf of my uncle)
We have various databases and we need to somehow visualise the common elements among them.
For example we could have a database of people, and multiple databases of events, and we would like to see if one person went to two events, who else went to the same two events?


Now, I have never really done any work with proper databases in years, so have no clue where to start. After some reading I came accross ER diagrams, are these just to show you the layout, or can you actually query them?

Many thanks
Dave

no, you cannot query a diagram, you can only query tables

if you could show the layout of your people and events tables, maybe we can have a crack at helping you with the query

and as for where to post, don't do it here in the introductions, do it in the appropriate forum for the database system you're using (postgresql, mysql, db2, whatever)

Thanks for your reply r937

Sorry for all the newbie questions!

Aparently the different sources of data are in different formats. Is there one solution to query different databases? And which section should I then post in?

I can find out the layout of each table, what is the best program to use to draw an entity relationship diagram to show you guys?

Thanks
Dave

as to where the 'right' forum to post your question...
it all depends
if you are at the conceptual level (ie a theoretical how do I do this.....) then the concepts forum is probably your best bet

if you have already committed to a specific database then posting in that forum would be a smarter call

if you want a diagrammng tool to visualise the current db's then there are several candidates, most are database specific byt there are some free to air tools out there.

Hello Dave.

Thanks guys, I will try to post in the correct forum now!

Hi everyone. I'm new here also. Hope to enjoy my stay here.