[Axis2] Service Settings, DB connection

[Oliver Hirschi <o....@bluewin.ch>]

Hi there,

I have to implement several webservice with DB connections to a
mysql-database. Now I have two questions about the implementing of
that:

1. Where should I store the db-connection parameters. Now I have
integrated it to service.xml! It works fine, but if I make the
deployment of the services I generate an ".aar" file which includes
also the service.xml. This implicates, that by updating the service on
a server, the service.xml is also overwritten, it means the
customer-settings (like db connection parameters, etc.) are lost and
have to set again.
Is there a better place to store such settings?

2. I connect to db in the startUp method of an additional service-class
implementing the ServiceLifeCycle interface and stores it to a
service-parameter (the disconnecting is made in the shutDown method).
So from the serveral service-methods I can acces the db-connection
object over the servicecontext. It runs well.
Now, my question is, was happens, if there comes several requests to
services wich used the db-connection from different clients at the same
time? I think there is only one db-connection object instance, so there
can occur access violations, isn't it?

Many thanks & Regards,
-- 
Oliver Hirschi
http://www.FamilyHirschi.ch 



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Re: [Axis2] Service Settings, DB connection

[Ognjen Blagojevic <og...@etf.bg.ac.yu>]

Hi Oliver,

> 1. Where should I store the db-connection parameters. Now I have
> integrated it to service.xml! It works fine, but if I make the
> deployment of the services I generate an ".aar" file which includes
> also the service.xml. This implicates, that by updating the service on
> a server, the service.xml is also overwritten, it means the
> customer-settings (like db connection parameters, etc.) are lost and
> have to set again.
> Is there a better place to store such settings?

Do you really want to allow your customers to change DB connection 
parameters? This doesn't look like a very good decision.

Anyway, if they can change them, then you must put them somewhere 
outside the database, i.e. in file system. Since you overwrite .aar file 
each time you deploy your service you could use some other place in the 
file system.


> 2. I connect to db in the startUp method of an additional service-class
> implementing the ServiceLifeCycle interface and stores it to a
> service-parameter (the disconnecting is made in the shutDown method).
> So from the serveral service-methods I can acces the db-connection
> object over the servicecontext. It runs well.
> Now, my question is, was happens, if there comes several requests to
> services wich used the db-connection from different clients at the same
> time? I think there is only one db-connection object instance, so there
> can occur access violations, isn't it?

Yes. You could use locking to prevent this. Even better, you could add 
conncetion pooling to your application, plus, open the connection before 
writing to database, and close it afterwards. Connection is a valuable 
resource, and you shouldn't keep it open all the time.

Regards,
Ognjen

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