Question: I am designing a database for use in an information system. It will have data on customers, employees and items. Needless to say, the customers section alone has about a dozen tables.

I would like to know if it's bad practise to split this data over multiple DBs and then just refer amongst them, or if keeping them all in the same DB would be better.

So, rather having a single DB (e.g. **Company\_DB**) with two dozen tables (e.g `CUS_DETAILS`, `EMP_DETAILS`, etc), would it be better to have two DBs (**Company\_Cus, Company\_Emp**) with the `CUS_DETAILS` in one and `EMP_DETAILS` in the other?

Regards.

Answer: 
I think it's better to have it all in one database, rather than having data scattered throughout several databases.

Personally I think the only reason to separate information in different databases would be to have systems or sub-systems, totally different from each other, on a single platform.

The amount of data will be the same, regardless of how many databases you use.
> 
> I would go for a single DB,unless it really not necessary to split
>  into multiple data sources a single DB is not limited to dozen of
>  tables.
> 
> 
> 

There will be always a headache enough to manage multiple resources.