Thread: Hello World

Hi,

first of all I'll have to confess I don't know next to nothing at all
about JAVA, yet.
On the other hand I'm not exactly new to programming nor PostgreSQL either.

Is there a "Hello World" level sample for jdbc with PG?

Lets suppose I allready have a running PG with a db db_test that has a
few tables among which there is tbl_test in schema s.
The db-server might be 192.168.0.100.
User could be "user1" with password "pw1".

What would be minimally needed to connect to db_test and read the
content of tbl_test to the console and logg off from PG.

I'd prefer a complete sample code that could be dumped through javac.

Andreas wrote:
> Hi,
>
> first of all I'll have to confess I don't know next to nothing at all
> about JAVA, yet.
> On the other hand I'm not exactly new to programming nor PostgreSQL either.
>
> Is there a "Hello World" level sample for jdbc with PG?

I'd suggest to read the Java Tutorial by Sun:

http://java.sun.com/docs/books/tutorial/

and after you got the basics, move on to the JDBC trail of the tutorial:

http://java.sun.com/docs/books/tutorial/jdbc/index.html

> Lets suppose I allready have a running PG with a db db_test that has a
> few tables among which there is tbl_test in schema s.
> The db-server might be 192.168.0.100.
> User could be "user1" with password "pw1".
>
> What would be minimally needed to connect to db_test and read the
> content of tbl_test to the console and logg off from PG.
>
> I'd prefer a complete sample code that could be dumped through javac.

A sample attached. Save it to a file called JdbcTest.java, modify the
server address, database name, table name etc. to suite your needs, and
compile with "javac JdbcTest.java". To run, add postgresql.jar to your
classpath. For example:

java -cp path/to/postgresql.jar JdbcTest

--
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com
import java.sql.*;

public class JdbcTest {
    public static void main(String[] args) throws Exception
    {
        Class.forName("org.postgresql.Driver");
        Connection conn = DriverManager.getConnection("jdbc:postgresql://localhost/testdb", "username", "pw");

        ResultSet rs = conn.prepareStatement("SELECT * FROM test").executeQuery();
        while(rs.next())
            System.out.println(rs.getString(1));
    }
}

Have a look at this file:

http://www.pensament.net/java/other_plugins.html#postgresql
http://www.pensament.net/java/PostgreSQL_.java

It shows how to connect and insert/query an image as bytea. Works on top of
ImageJ http://rsb.info.nih.gov/ij/ , a public domain minimalistic java image
processing application.

Albert
--
Albert Cardona
Molecular Cell Developmental Biology
University of California Los Angeles
Tel +1 310 2067376
Programming: http://www.ini.unizh.ch/~acardona/trakem2.html
Research: http://www.mcdb.ucla.edu/Research/Hartenstein/
Web design: http://www.pixelets.com

Andreas wrote:

> Hi,
>
> first of all I'll have to confess I don't know next to nothing at all
> about JAVA, yet.
> On the other hand I'm not exactly new to programming nor PostgreSQL
> either.

http://java.sun.com/docs/books/tutorial/jdbc/index.html

Just follow this tutorial step by step.

HTH
ido

Could not find anything more "Hello World" than this :-)

http://www.fankhausers.com/postgresql/jdbc/


--Imad
www.EnterpriseDB.com


On 11/21/06, Michael Schmidt <michaelmschmidt@msn.com> wrote:
>
>
>
> Andreas,
> I was in a similar situation about two years ago and have, slowly, learned a
> bit about Java.  Java itself is deceptively simple but to use it
> effectively, you will want to use one of the IDE platforms.  I chose Eclipse
> over the others because it allows native access to SWT and JFace, and
> because it is open-source and free (like PostgreSQL).  Eclipse has a pretty
> steep learning curve, but being a stubborn German, I stuck with it and now
> am able to do most things fairly easily.  For the beginner, I would
> recommend investing in the Designer or RCP builder plug-in from
> Instantiations.
>
> Working on my application, I realized that I could start by writing a basic,
> generic UI and then add custom features specific to my application later.  I
> made the generic UI available at PgFoundry (the Komo project).  It includes
> database access (password and other settings), as well as general utilities
> (back up, restore, vacuum).  The code isn't perfect, but it works.
> Hopefully, this will serve as the "Hello World" application you are looking
> for.  Here's the link
> http://pgfoundry.org/projects/komo-client/
>
> Michael Schmidt
>
>
> ----- Original Message -----
> From: Andreas
> To: pgsql-jdbc@postgresql.org
> Sent: Monday, November 20, 2006 11:00 PM
> Subject: [JDBC] Hello World
>
> Hi,
>
> first of all I'll have to confess I don't know next to nothing at all
> about JAVA, yet.
> On the other hand I'm not exactly new to programming nor PostgreSQL either.
>
> Is there a "Hello World" level sample for jdbc with PG?
>
> Lets suppose I allready have a running PG with a db db_test that has a
> few tables among which there is tbl_test in schema s.
> The db-server might be 192.168.0.100.
> User could be "user1" with password "pw1".
>
> What would be minimally needed to connect to db_test and read the
> content of tbl_test to the console and logg off from PG.
>
> I'd prefer a complete sample code that could be dumped through javac.
>
>
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