# To use multiple databases, sets of tables or rails applications

**URL:** <https://www.ruby-forum.com/t/to-use-multiple-databases-sets-of-tables-or-rails-applications/153632>\
**Category:** Rails\
**Created:** [November 19, 2008, 4:43pm UTC](https://www.ruby-forum.com/t/to-use-multiple-databases-sets-of-tables-or-rails-applications/153632 "2008-11-19T16:43:25Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![anthony](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/49beb7/32.png) [@anthony](https://www.ruby-forum.com/u/anthony)\
**Post date:** [November 19, 2008, 4:43pm UTC](https://www.ruby-forum.com/t/to-use-multiple-databases-sets-of-tables-or-rails-applications/153632/1 "2008-11-19T16:43:25Z")

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This is not a request about how to accomplish connections to multiple  
databases, etc…

But, I am looking for advise on the best way to start a new project. I  
will have multiple clients, each will want their data protected from  
the other clients. I would probably have up to about 10 tables per  
client.

The question is, in order to keep the data secure and separate, yet  
have a maintainable rails app, what is the best approach to designing  
the database and application workflow:

1. Create One rails app that connects to One database and creates a  
new set of 10 tables per client and then put in the logic to only  
allow changes and views on those 10 tables?

2. Create One rails app that connects to Multiple databases, one for  
each client?

3. Create Multiple rails apps, on for each client, that each connect  
to one database containing the 10 tables for the client.

Then I would use something like [client1.domain.com](http://client1.domain.com) and  
[client2.domain.com](http://client2.domain.com) to tell my rails app which set of data to connect  
to.

I obviously need a solution that I can maintain. Ideally would it be a  
big pain to start with the one db, multiple sets of tables idea and  
then migrate to one of the other options if my client list grows?

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**Author:** ![anthony](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/49beb7/32.png) [@anthony](https://www.ruby-forum.com/u/anthony)\
**Post date:** [November 19, 2008, 5:48pm UTC](https://www.ruby-forum.com/t/to-use-multiple-databases-sets-of-tables-or-rails-applications/153632/2 "2008-11-19T17:48:04Z")

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On Nov 19, 9:40 am, Anthony [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> This is not a request about how to accomplish connections to multiple  
> databases, etc…
> 
> But, I am looking for advise on the best way to start a new project. I  
> will have multiple clients, each will want their data protected from  
> the other clients. I would probably have up to about 10 tables per  
> client.

I’m assuming all 10 tables are actually the same for each client,  
right? Just have an 11th table - “clients”. Relate your other tables  
to the clients table, and use the power of ActiveRecord to query for  
all the data you need for a specific client.

You can use a before\_filter in your application controller to look at  
the subdomain to discover which client you’re supposed to be using.

Jeff

[purpleworkshops.com](http://purpleworkshops.com)

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<div class="post-metadata">

**Author:** ![anthony](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/49beb7/32.png) [@anthony](https://www.ruby-forum.com/u/anthony)\
**Post date:** [November 19, 2008, 6:16pm UTC](https://www.ruby-forum.com/t/to-use-multiple-databases-sets-of-tables-or-rails-applications/153632/3 "2008-11-19T18:16:15Z")

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> I’m assuming all 10 tables are actually the same for each client,  
> right? Just have an 11th table - “clients”. Relate your other tables  
> to the clients table, and use the power of ActiveRecord to query for  
> all the data you need for a specific client.
> 
> You can use a before\_filter in your application controller to look at  
> the subdomain to discover which client you’re supposed to be using.

That sounds super convenient, but wouldn’t it lead to really bloated  
tables and slow searches in the long run? I think I would vote for  
option #2, individual databases for each client. Also, obviously they  
would be backed up, but this would also prevent one database getting  
hosed from knocking out all your clients.

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**Author:** ![anthony](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/49beb7/32.png) [@anthony](https://www.ruby-forum.com/u/anthony)\
**Post date:** [November 20, 2008, 1:21pm UTC](https://www.ruby-forum.com/t/to-use-multiple-databases-sets-of-tables-or-rails-applications/153632/4 "2008-11-20T13:21:33Z")

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You might want to take a look here  
[http://railsforum.com/viewtopic.php?id=20582](http://railsforum.com/viewtopic.php?id=20582)