# If you want to disconnect a database properly, there is the

**URL:** <https://www.ruby-forum.com/t/if-you-want-to-disconnect-a-database-properly-there-is-the/97838>\
**Category:** Rails\
**Created:** [January 26, 2006, 10:38pm UTC](https://www.ruby-forum.com/t/if-you-want-to-disconnect-a-database-properly-there-is-the/97838 "2006-01-26T22:38:46Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![sayoyo](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ba8739/32.png) [@sayoyo](https://www.ruby-forum.com/u/sayoyo)\
**Post date:** [January 26, 2006, 10:38pm UTC](https://www.ruby-forum.com/t/if-you-want-to-disconnect-a-database-properly-there-is-the/97838/1 "2006-01-26T22:38:46Z")

</div>

Hi,

We have worked on a problem of connection: Connect to  
two databases with a single ActiveRecord::Base model  
class within the same action  
The main difficulty is how to disconnect the actual  
connection properly and then let the ActiveRecord  
establishes a new one.  
The actual function “remove\_connection” removes the  
connection, but its doesn’t unbind the link between  
rails and the database.  
So we decide to add some new methodes in order to  
remove all link between rails and the database.

First, we added a new methode to the adapter, we are  
using postgresql, the following code is written for  
postgresql\_adapter.rb  
if you are using another database, you have to rewrite  
it. In postgresql\_adapter.rb, add the follong code

```
  def disconnect
if (@connection != nil) then
	# methode "close" is exported by the postgres.so for

```

disconnect the database  
@connection.close  
@connection = nil # clear the connection  
end  
end

In connection\_specification.rb, add the following code  
at the end (in the “ActiveRecord::Base” class section)

def self.clear\_connection(klass=self)  
@@defined\_connections.delete(klass) # remove  
the connection  
ac = active\_connections # get the active  
connection  
ac.delete(klass) if ac.kind\_of?(Hash) #  
remove the connection  
self.connection.disconnect # disconnect the  
link with database, it call the newly added methode in  
postgresql\_adapter  
@connection = nil # remove the connection  
cached in the ActiveRecord::base class  
end

For the tests, we have used the following code:

```
# first connection
GenTableAs.establish_connection(:adapter =>

```

“postgresql”,  
:host =\> “1.2.3.4”,  
:port =\> 5432,  
:database =\> “db1”,  
:username =\> “dbuser1”,  
:password =\> “dbuser1”)

```
GenTableAs.set_table_name 'table_no_1'
	GenTableAs.reset_column_information()
	obj1 = GenTableAs.new
	@col1 = obj1.class.column_names()

obj1["colaa"] = 123
obj1["colab"] = "123"
obj1.save
obj1 = nil

GenTableAs.clear_connection	# here we disconnect the

```

connection

```
# connection to a new database
GenTableAs.establish_connection(:adapter =>

```

“postgresql”,  
:host =\> “9.8.7.5”,  
:port =\> 5432,  
:database =\> “db2”,  
:username =\> “dbuser2”,  
:password =\> “dbuser2”)

```
GenTableAs.set_table_name "table_no_42"
	GenTableAs.reset_column_information()
	obj1 = GenTableAs.new
	@col2 = obj1.class.column_names()

obj1["col12"] = 456
obj1["col34"] = "789"
obj1.save
	obj1 = nil
GenTableAs.clear_connection	# here we disconnect

```

again the connection

It should give us the name of the columns of two  
different tables of different database in @col1 and  
@col2 and save the data to  
tables.

So hope this will help who which to do the same thing,  
(Actually, it takes us a few days to fully understand  
the mecanism of the  
database connection:))

If anyone has any comments about this, please  
communicate with us:)!!!

Thanks you very much

Saiho

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