Merge and combine different data from databases

[jaz1988 <88...@gmail.com>]

Hi!

Currently I have a DB named myDB and myDB consists of a few tables in it.
Lets say I want to write to myDB from different computers concurrently(each
computer will have its own myDB), how do I merge and combine the DB from
each computer into 1 central DB at the end of the day?

Is there a proper way to it in Apache Derby?

Thanks!
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Re: Merge and combine different data from databases

[Bryan Pendleton <bp...@gmail.com>]

> Currently I have a DB named myDB and myDB consists of a few tables in it.
> Lets say I want to write to myDB from different computers concurrently(each
> computer will have its own myDB), how do I merge and combine the DB from
> each computer into 1 central DB at the end of the day?

One technique is to use a single Network Server instance, and a single
physical DB, but multiple database schemas, one for each computer.

Each computer connects to the server and reads and writes data from its own
set of tables in its separate schema.

A separate application can then connect and use UNION VIEW syntax to
view the various separate tables as unified larger tables containing
all the data, union-ed together.

thanks,

bryan

Re: Merge and combine different data from databases

[Rick Hillegas <ri...@oracle.com>]

On 6/13/12 10:02 PM, jaz1988 wrote:
> Hi!
>
> Currently I have a DB named myDB and myDB consists of a few tables in it.
> Lets say I want to write to myDB from different computers concurrently(each
> computer will have its own myDB), how do I merge and combine the DB from
> each computer into 1 central DB at the end of the day?
>
> Is there a proper way to it in Apache Derby?
>
> Thanks!
If each machine really has to have its own database, and you can't use a 
central server as Bryan suggests, then you might take a look at the 
ForeignTableVTI attached to 
https://issues.apache.org/jira/browse/DERBY-4962. This table function is 
useful for the sort of end-of-the-day data integration problem you 
describe. Essentially what you would do is this:

1) In the central database, create a separate schema for each of the 
satellite databases.

2) Then, in each schema, use ForeignTableVTI to declare views which will 
siphon the data out of the corresponding satellite.

Hope this helps,
-Rick