What is the best way to interact with a JDBC database

[Venks]

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Hi,

I have a database that has only JDBC connectivity but I need to interact to
this database from Ruby. What's the best way to do so? All ideas and
suggestions are welcome.

My initial thought is to create a Java program that accepts connection
information and a SQL statement and execute the SQL against the database.
Assuming that I have this program, what's the best way to call this Java
program from Ruby?

I looked at JRuby and didn't feel that's the right answer.

Regards,

-Venks

 

[Dan]

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Just out of interest, what was your problem with JRuby?

I had a similar issue with an Oracle RDB database running on VMS that only
has .NET (beta) and JDBC drivers. So I went with JRuby using
activerecord-jdbc and it has been working rather well for me. A few minor
issues here and there, but nothing major.

 

[Venks]

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It's a science/research project called "MonetDB".

 

[Venks]

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Actually, I haven't tried Jruby except reading about it. I am using Ruby as
a glue to put together all the tasks I need including Database access, File
I/O and all the stuff that comes with a heavy duty batch programming. It's
my understanding that JRuby doesn't provide all the classes and I would like
to avoid using JRuby just for this requirement of accessing a JDBC database.

 

[Reid Thompson]

It's a science/research project called "MonetDB".

from the website...There are application bindings for MonetDB/SQL using JDBC,
ODBC, PHP, Python, Perl and C,... so you could probably work the C binding into
Ruby in some fashion.

 

[Thomas Enebo]

Actually, I haven't tried Jruby except reading about it. I am using Ruby as
a glue to put together all the tasks I need including Database access, File
I/O and all the stuff that comes with a heavy duty batch programming. It's
my understanding that JRuby doesn't provide all the classes and I would like
to avoid using JRuby just for this requirement of accessing a JDBC database.

Out of personal interest...Which classes are missing for you in JRuby?
We have an interest in filling in gaps in our implementation.

-Tom

 

[Venks]

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I don't know if any classes are missing. I was just reading the
documentation that suggested that all the classes may not be
available. Also, I have not used JRuby yet (As a matter of fact I am new to
Ruby let alone developing in a OO language environment)

Thanks for all the feedback. I was thinking whether SOAP may be an option,
but could be over kill just for bridging the gap between Ruby and Java.

I will try to use Jruby to access the JDBC database. Please allow me to
specify in few steps to describe the overall picture of my batch job:

- I have a bunch of Ruby modules that access many MySQL databases across
several machines.
- I also have lot of System calls to create data into files which I then I
transfer between different databases (not just MySQL).
- Somewhere in this process I need to invoke a method from a module that's
developed using JRuby.
- When I invoke the JRuby module, I except the Java environment to be
active, otherwise I don't need JVM.
- Once I am done with the Jruby module, I will continue further processing
using regular Ruby modules.

Does this makes sense?

Thanks,

 

[Thomas Enebo]

I don't know if any classes are missing. I was just reading the
documentation that suggested that all the classes may not be
available. Also, I have not used JRuby yet (As a matter of fact I am new to
Ruby let alone developing in a OO language environment)

Thanks for all the feedback. I was thinking whether SOAP may be an option,
but could be over kill just for bridging the gap between Ruby and Java.

My main comment is that JRuby "is" Ruby in the sense that you can write
as much Ruby as you want and JRuby is capable of running it. So write
your app in Ruby and execute/run it in JRuby. We are meant to be a
drop-in alternative to Ruby.

So I would not think so much as things being a JRuby module or a Ruby
Module. The caveat to that last sentence is that in addition to being
able to run Ruby in JRuby you can also access/use Java classes from
within JRuby. So code in Ruby and bring in the Java classes you need
into your app (in this case JDBC) to do what you need in all your
databases. OR....

Install activerecord-JDBC gem and then use activerecord APIs to interact
with your databases. This does have one limitation that we only
support the more popular databases at this point. Less known ones will
not work (though we are looking for help in adding support to more
databases). The main benefit is that this will end up making your code
Java-free (behind the scenes our gem is using Java code, but it is
transparent to you).

I will try to use Jruby to access the JDBC database. Please allow me to
specify in few steps to describe the overall picture of my batch job:

- I have a bunch of Ruby modules that access many MySQL databases across
several machines.
- I also have lot of System calls to create data into files which I then I
transfer between different databases (not just MySQL).

A question? When you say system calls to create data into files, do you
just mean using things like Ruby's File class? That is no problem if so.

- Somewhere in this process I need to invoke a method from a module that's
developed using JRuby.
- When I invoke the JRuby module, I except the Java environment to be
active, otherwise I don't need JVM.

I recommend just running your whole Ruby application in JRuby.

- Once I am done with the Jruby module, I will continue further processing
using regular Ruby modules.

Does this makes sense?

Thanks,

-Tom

 

[Venks]

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Hi,

- I am using the MySQL Driver which has one-to-one correspondence to "C"
API. I may need to have more control on how I access MySQL. It's my
understanding that Active record is based on DBI interface and has an
additional layer.
- The system calls I mentioned below are not File I/O. I am using the File
I/O class too. But the system calls I am referring is directly calling OS
commands as I use "sed, "gpg", "zip" and some other UNIX utilities.

Now here is question which I am sure you are not reading/listening for the
first time.

Are there any performance issues between Ruby and JRuby (I know this has
been asked many times but couldn't find any definitive answer/article)

Thanks,

 

[Thomas Enebo]

Hi,

- I am using the MySQL Driver which has one-to-one correspondence to "C"
API. I may need to have more control on how I access MySQL. It's my
understanding that Active record is based on DBI interface and has an
additional layer.

Well the issue with using the MySQL Driver is that it requires a native
C extension to work. Currently, JRuby does not support C extensions.
Your code will either have to use the pure Ruby MySQL driver (not very
fast) or start using JDBC directly. So this unfortunately will require
extra work.

- The system calls I mentioned below are not File I/O. I am using the File
I/O class too. But the system calls I am referring is directly calling OS
commands as I use "sed, "gpg", "zip" and some other UNIX utilities.

We can call out using system and friends. I think there is a couple of
bugs with bi-directional communication using popen, but I suspect things
will work for you here.

Now here is question which I am sure you are not reading/listening for the
first time.

Are there any performance issues between Ruby and JRuby (I know this has
been asked many times but couldn't find any definitive answer/article)

No real performance issues. We have a few bottlenecks which could
surface, but we are faster in many areas and slower in some others. All
in all our performance is looking really good.

-Tom