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Posted to torque-user@db.apache.org by Mehmet Erdem <me...@rwth-aachen.de> on 2007/04/18 17:40:18 UTC
How to make the default database settable during runtime?
Hi,
I am using Torque 3.2 and I try to make the default database settable
during runtime.
I created a class DefaultDatabase with a static method getName() that
takes the default
database name from a property file.
Then I modified the MapBuilder.vm and Peer.vm to refer to this getName()
method instead of the template variable $table.Database.Name.
MapBuilder.vm:
< dbMap = Torque.getDatabaseMap(DefaultDatabase.getName());
---
> dbMap = Torque.getDatabaseMap("$table.Database.Name");
Peer.vm:
< public static final String DATABASE_NAME = DefaultDatabase.getName();
<
---
> public static final String DATABASE_NAME = "$table.Database.Name";
>
So is this the right way to make the default database settable. Or did I
miss something ? It seems
unlikely that I am the only one so far who wants to change the database
without regenerating
classes.
Thanks,
Mehmet Erdem
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Re: How to make the default database settable during runtime?
Posted by Mehmet Erdem <me...@rwth-aachen.de>.
I really did not understand that there is a torque schema database name
which is independent
of the real database name ;-).
What I tried to achieve was very simple. During runtime I wanted to have
another db database name than the
torque schema database name that is used in the generated classes. It
turns out that this simply
means that I have to set the db database name in the connection url of
the torque.properties file.
torque.database.default=TORQUE_DATABASE_NAME
...
torque.dsfactory.TORQUE_DATABASE_NAME.connection.url =
jdbc:mysql://127.0.0.1/DB_DATABASE_NAME
Thanks for your detailed answer,
Mehmet
Greg Monroe wrote:
> First lets make sure we have all the definitions correct
> here because the term "database name" has been WAY
> overloaded and folks get the variations confused.
>
> Torque's Schema Database name:
>
> This is a compile time value that is used to connect
> the OM layer objects with their schema info (Map objects)
> and find the DB connection info.
>
> DB Server Database name:
>
> This is a DB specific collection of tables, e.g. a
> Catalog in MySQL, a Database in MS SQL, and the like.
>
> The only relationship between these two "database
> names" is that the Torque initialization properties
> map the Schema database name to the Server Database
> name. Specifically, via the JDBC connection info.
>
> That said, the base question here is: What are you
> trying to accomplish here.
>
> Are you are trying to have MULTIPLE application
> instances (e.g. different web apps) using the same OM
> layer but accessing different Database server databases?
> Maybe with the server info coming from some external
> source (e.g. user supplied property or a DB table).
>
> In this case, it easy to dynamically create a
> Configuration object that maps the Torque database
> schema name to your DB Server database. Then use this
> with the Torque.init(Configuration ) method.
>
> If you are trying to use the same OM layer in the SAME
> application to access different server databases, life
> becomes a lot more complicated. You have to start
> thinking about multiple threads using different DB
> info (in both senses of the word) and how not to have
> transactions start on one server and end on another
> (because another thread changed the DB info).
>
> Currently, the best way to do this is to write your
> code using the methods that include a Connection
> object, e.g, RecordPeer.doSelect(c, conn); For the most
> part, these methods will perform the actions using the
> specified connections. I think most of the areas
> that used to "automagically" get connection have been
> fixed so any method with a connection specified will use
> it all the way down.
>
> That said, you can then use Torque's DB pooling to
> manage your connections by using the
> Torque.getConnection(DBName) method and initializing
> Torque with multiple Schema database names. These
> can be in your Torque init properties file or dynamically
> created (as per above).
>
>
>> -----Original Message-----
>> From: Mehmet Erdem [mailto:mehmet.erdem@rwth-aachen.de]
>> Sent: Wednesday, April 18, 2007 11:40 AM
>> To: torque-user@db.apache.org
>> Subject: How to make the default database settable during runtime?
>>
>> Hi,
>>
>> I am using Torque 3.2 and I try to make the default database settable
>> during runtime.
>>
>> I created a class DefaultDatabase with a static method getName() that
>> takes the default
>> database name from a property file.
>>
>> Then I modified the MapBuilder.vm and Peer.vm to refer to
>> this getName()
>> method instead of the template variable $table.Database.Name.
>>
>> MapBuilder.vm:
>>
>> < dbMap = Torque.getDatabaseMap(DefaultDatabase.getName());
>> ---
>> > dbMap = Torque.getDatabaseMap("$table.Database.Name");
>>
>>
>> Peer.vm:
>>
>> < public static final String DATABASE_NAME =
>> DefaultDatabase.getName();
>> <
>> ---
>> > public static final String DATABASE_NAME =
>> "$table.Database.Name";
>> >
>>
>>
>> So is this the right way to make the default database
>> settable. Or did I
>> miss something ? It seems
>> unlikely that I am the only one so far who wants to change
>> the database
>> without regenerating
>> classes.
>>
>> Thanks,
>>
>> Mehmet Erdem
>>
>>
>> ---------------------------------------------------------------------
>> To unsubscribe, e-mail: torque-user-unsubscribe@db.apache.org
>> For additional commands, e-mail: torque-user-help@db.apache.org
>>
>>
>>
>
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>
>
>
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>
>
>
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RE: How to make the default database settable during runtime?
Posted by Greg Monroe <Gr...@DukeCE.com>.
First lets make sure we have all the definitions correct
here because the term "database name" has been WAY
overloaded and folks get the variations confused.
Torque's Schema Database name:
This is a compile time value that is used to connect
the OM layer objects with their schema info (Map objects)
and find the DB connection info.
DB Server Database name:
This is a DB specific collection of tables, e.g. a
Catalog in MySQL, a Database in MS SQL, and the like.
The only relationship between these two "database
names" is that the Torque initialization properties
map the Schema database name to the Server Database
name. Specifically, via the JDBC connection info.
That said, the base question here is: What are you
trying to accomplish here.
Are you are trying to have MULTIPLE application
instances (e.g. different web apps) using the same OM
layer but accessing different Database server databases?
Maybe with the server info coming from some external
source (e.g. user supplied property or a DB table).
In this case, it easy to dynamically create a
Configuration object that maps the Torque database
schema name to your DB Server database. Then use this
with the Torque.init(Configuration ) method.
If you are trying to use the same OM layer in the SAME
application to access different server databases, life
becomes a lot more complicated. You have to start
thinking about multiple threads using different DB
info (in both senses of the word) and how not to have
transactions start on one server and end on another
(because another thread changed the DB info).
Currently, the best way to do this is to write your
code using the methods that include a Connection
object, e.g, RecordPeer.doSelect(c, conn); For the most
part, these methods will perform the actions using the
specified connections. I think most of the areas
that used to "automagically" get connection have been
fixed so any method with a connection specified will use
it all the way down.
That said, you can then use Torque's DB pooling to
manage your connections by using the
Torque.getConnection(DBName) method and initializing
Torque with multiple Schema database names. These
can be in your Torque init properties file or dynamically
created (as per above).
> -----Original Message-----
> From: Mehmet Erdem [mailto:mehmet.erdem@rwth-aachen.de]
> Sent: Wednesday, April 18, 2007 11:40 AM
> To: torque-user@db.apache.org
> Subject: How to make the default database settable during runtime?
>
> Hi,
>
> I am using Torque 3.2 and I try to make the default database settable
> during runtime.
>
> I created a class DefaultDatabase with a static method getName() that
> takes the default
> database name from a property file.
>
> Then I modified the MapBuilder.vm and Peer.vm to refer to
> this getName()
> method instead of the template variable $table.Database.Name.
>
> MapBuilder.vm:
>
> < dbMap = Torque.getDatabaseMap(DefaultDatabase.getName());
> ---
> > dbMap = Torque.getDatabaseMap("$table.Database.Name");
>
>
> Peer.vm:
>
> < public static final String DATABASE_NAME =
> DefaultDatabase.getName();
> <
> ---
> > public static final String DATABASE_NAME =
> "$table.Database.Name";
> >
>
>
> So is this the right way to make the default database
> settable. Or did I
> miss something ? It seems
> unlikely that I am the only one so far who wants to change
> the database
> without regenerating
> classes.
>
> Thanks,
>
> Mehmet Erdem
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: torque-user-unsubscribe@db.apache.org
> For additional commands, e-mail: torque-user-help@db.apache.org
>
>
Duke CE Privacy Statement
Please be advised that this e-mail and any files transmitted with it are confidential communication or may otherwise be privileged or confidential and are intended solely for the individual or entity to whom they are addressed. If you are not the intended recipient you may not rely on the contents of this email or any attachments, and we ask that you please not read, copy or retransmit this communication, but reply to the sender and destroy the email, its contents, and all copies thereof immediately. Any unauthorized dissemination, distribution or copying of this communication is strictly prohibited.
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