newbie questions about ojb setup with my database

[Michael Harrison <go...@alumni.princeton.edu>]

Hello, all. I'm very new to OJB, and I'm very excited about it. I've 
been reading the extensive documentation at db.apache.org, and I've 
managed to get OJB set up. I have a question, however, about configuring 
OJB to work with my MySQL database.

I'm not only new to OJB, but new to Ant and building (I've been in the 
interpreted throw-away scripting world for a long time), so part of what 
I need to learn stems from my ignorence there. After I downloaded OJB 
and expanded everything, I followed the instructions at platforms.html 
to set up a test database. I "switched on" the line for the MySQL 
profile. I also edited the mysql.profile with the proper jdbc url info, 
username, password, etc.  I understood that two things were happening at 
once: 1) the build process was creating the necessary OJB internal 
tables, not all of which (or any necessarily?) are required; and 2) the 
build process was creating and populating tables for the example 
database, which simulates an actual production db.

Here are my questions:

When I want to use OJB to connect to my own production db, do I need to 
run the build again, against a new build.xml file; or is it already set 
up to use MySQL, and I only have to alter a few configuration files for 
the new jdbc url, password, etc?

The file repository_database.xml contains a jdbc-connection-descriptor 
with attributes like jcd-alias="@JCD_ALIAS@"  I'm not familiar with 
@foo@ notation--does this mean there is supposed to be a 
previously-defined value for some JCD_ALIAS token or entity? Or is this 
a placeholder that I should replace with real values?

Also, what is the relationship between the repository_database.xml file 
and the values I set in mysql.profile before the build? Is the build 
supposed to write this XML file out?

If I need to rerun the build, how do I avoid creating all the example 
tables?

I apologize for the newbie questions. I'm climbing a steep learning 
curve, and I'm probably not being as patient as I should be. Help me 
out, and I promise I'll find much more interesting questions soon enough.

Best Regards,

Michael

||

Re: newbie questions about ojb setup with my database

[Oki DZ <ok...@pindad.com>]

On Sun, Mar 30, 2003 at 06:22:07PM -0500, Michael Harrison wrote:
> When I want to use OJB to connect to my own production db, do I need to 
> run the build again, against a new build.xml file; or is it already set 

No, you don't need to run the build again.

> up to use MySQL, and I only have to alter a few configuration files for 
> the new jdbc url, password, etc?

I could get it run in standalone-mode by having the following xml files 
in a directory (the program's home):
repository.xml
repository_database.xml
repository_internal.xml
repository_user.xml

The contents of repository.xml, are basically:
<descriptor-repository version="1.0" isolation-level="read-uncommitted">
    &database;
    &internal;
    &user;
</descriptor-repository>
 
> The file repository_database.xml contains a jdbc-connection-descriptor 
> with attributes like jcd-alias="@JCD_ALIAS@"  I'm not familiar with 
> @foo@ notation--does this mean there is supposed to be a 
> previously-defined value for some JCD_ALIAS token or entity? Or is this 
> a placeholder that I should replace with real values?

You can change it to "default":
<!-- this connection was used as the default one within OJB -->
<jdbc-connection-descriptor
  jcd-alias="default"
  default-connection="true"
  platform="MySQL"
  jdbc-level="2.0"
...

Later, you can get that default connection by
PersistenceBroker broker = 
	PersistenceBrokerFactory.defaultPersistenceBroker();

To have the repository.xml getting read, make sure that your program's 
home is set to the directory where that repository resides. This can be 
done via ant:
  <target name="execute" depends="compile" description="execute the 
app">
    <exec dir="${ojbhome}" executable="${javahome}/bin/java">
      <arg line="-classpath 
${distdir}:${commons-beanutils-jar}:${commons-collections-jar}:${commons-dbcp-jar}:${commons-lang-jar}:${commons-logging-jar}:${commons-pool-jar}:${ojb-jar}:${spy-jar}:${xerces-jar}:${j2ee-jar}"/>
      <arg line="com.<your main package>.Main"/>
    </exec>
  </target>

Somewhere above, ojbhome was set to the program's home dir.
 
> Also, what is the relationship between the repository_database.xml file 
> and the values I set in mysql.profile before the build? 

It would provide you with a connection defined in the file.

> Is the build  supposed to write this XML file out?

Yes; overwriting it, I mean.

Oki

OT:Best Practice for O/R-Mapping

[Joerg Lensing <in...@softcon-lensing.de>]

Hi,
is there any good book/site/newsgroup for O/R-Mapping?
I'm asking this for performance/maintaining

joerg

something not working as I expect it to

[Brill Pappin <br...@roguerobotics.com>]

I have a fairly simple object, who's ID I need to access.

in my descriptor for the object, I have the id field set to auto-increment
and as a primary key.

In the class, the id is initialized to -1 (All my classes, in all my
libraries initialize all instance members, even if only to null. this is
part of our standards and good programming practice in general).

What I am expecting, is that because I've set the id to auto-increment in
the descriptor, that when I create a new class, the ID is auto generated...
however what I get is the default value of the new object (-1 in this case).
Can I force ID's for a particular object to always be generated by the
database?

If not, what is the recommended way to force that generation?

I need the ID's because I'm working in a web environment and the id's are
often called from remote applications... not to mention legacy data/apps ;)
So, I need the ID field, but I also want the system to generate it for new
objects.

- Brill Pappin

Re: newbie questions about ojb setup with my database

[Brill Pappin <br...@roguerobotics.com>]

I've got a similar questions about those tokens.

I'm at the point of deploying the libs and a few tests to my development
server, however the tests seems to be failing because the tokens are not
being replaced.

I assume in the following (from repository-database.xml) that those values
are supposed to come from the OJB.properties file, however in my test output
it looks like they are not getting parsed.

<jdbc-connection-descriptor
     jcd-alias="@JCD_ALIAS@"
     default-connection="true"
     platform="@DBMS_NAME@"
     jdbc-level="@JDBC_LEVEL@"
     driver="@DRIVER_NAME@"
     protocol="@URL_PROTOCOL@"
     subprotocol="@URL_SUBPROTOCOL@"
     dbalias="@URL_DBALIAS@"
     username="@USER_NAME@"
     password="@USER_PASSWD@"
     batch-mode="false"
        useAutoCommit="1"
        ignoreAutoCommitExceptions="false"
     >

I imagine this is a common problem, so can anyone tell me where the failure
originates, or how to solve it?

- Brill Pappin

----- Original Message -----
From: "Michael Harrison" <go...@alumni.princeton.edu>
To: <oj...@db.apache.org>
Sent: Sunday, March 30, 2003 6:22 PM
Subject: newbie questions about ojb setup with my database


> Hello, all. I'm very new to OJB, and I'm very excited about it. I've
> been reading the extensive documentation at db.apache.org, and I've
> managed to get OJB set up. I have a question, however, about configuring
> OJB to work with my MySQL database.
>
> I'm not only new to OJB, but new to Ant and building (I've been in the
> interpreted throw-away scripting world for a long time), so part of what
> I need to learn stems from my ignorence there. After I downloaded OJB
> and expanded everything, I followed the instructions at platforms.html
> to set up a test database. I "switched on" the line for the MySQL
> profile. I also edited the mysql.profile with the proper jdbc url info,
> username, password, etc.  I understood that two things were happening at
> once: 1) the build process was creating the necessary OJB internal
> tables, not all of which (or any necessarily?) are required; and 2) the
> build process was creating and populating tables for the example
> database, which simulates an actual production db.
>
> Here are my questions:
>
> When I want to use OJB to connect to my own production db, do I need to
> run the build again, against a new build.xml file; or is it already set
> up to use MySQL, and I only have to alter a few configuration files for
> the new jdbc url, password, etc?
>
> The file repository_database.xml contains a jdbc-connection-descriptor
> with attributes like jcd-alias="@JCD_ALIAS@"  I'm not familiar with
> @foo@ notation--does this mean there is supposed to be a
> previously-defined value for some JCD_ALIAS token or entity? Or is this
> a placeholder that I should replace with real values?
>
> Also, what is the relationship between the repository_database.xml file
> and the values I set in mysql.profile before the build? Is the build
> supposed to write this XML file out?
>
> If I need to rerun the build, how do I avoid creating all the example
> tables?
>
> I apologize for the newbie questions. I'm climbing a steep learning
> curve, and I'm probably not being as patient as I should be. Help me
> out, and I promise I'll find much more interesting questions soon enough.
>
> Best Regards,
>
> Michael
>
> ||
>
>
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