billrobertson42 / pgjdbc

Postgresql JDBC Driver

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# PostgreSQL JDBC driver

Build Status

This is a simple readme describing how to compile and use the Postgresql JDBC driver.

Info

This isn't a guide on how to use JDBC - for that refer to Oracle's website and the JDBC tutorial.

For problems with this driver, refer to driver's home page and associated mailing list.

Downloading pre-built drivers

Most people do not need to compile PgJDBC. You can download prebuilt versions of the driver from the Postgresql JDBC site.

Compiling with Ant on the command line

PgJDBC doesn't natively support compilation from IDEs like Eclipse, NetBeans or IntelliJ. You should compile with ant on the command line.

Before you can compile the driver you must download the source code from git. You cannot compile from a jar or a .zip distribution. Run:

git clone https://github.com/pgjdbc/pgjdbc.git

to download the source code. (You'll need git installed, of course).

To compile you will need to have a Java 5 or newer JDK and will need to have Ant installed. To obtain Ant go to http://ant.apache.org/index.html and download the binary. Being pure Java it will run on virtually all Java platforms. If you have any problems please email the pgsql-jdbc list.

Once you have Ant, simply run ant using 'ant -lib lib' in the top level directory.
This will compile the correct driver for your JVM, and build a .jar file (Java ARchive) depending on the version of java and which release you have the jar will be named postgresql-.-.jdbc.jar. Where major,minor are the postgreSQL major,minor version numbers. release is the jdbc release number. N is the version of the JDBC API which corresponds to the version of Java used to compile the driver.

REMEMBER: Once you have compiled the driver, it will work on ALL platforms that support that version of the API. You don't need to build it for each platform.

Creating a distribution zip

To create a package of the driver jar, sources, and dependencies, run:

ant dist

Dependencies

PgJDBC has optional dependencies on other libraries for some features. These libraries must also be on your classpath if you wish to use those features; if they aren't, you'll get a PSQLException at runtime when you try to use features with missing libraries.

Ant will download additional dependencies from the Internet (from Maven respositories) to satisfy build requirements. Whether or not you intend to use the optional features the libraries used to implement them must be present to compile the driver.

Currently Waffle-JNA and its dependencies are required for SSPI authentication support (only supported on a JVM running on Windows). Unless you're on Windows and using SSPI you can leave them out when you install the driver.

Installing the driver

To install the driver, the postgresql.jar file has to be in the classpath. When running standalone Java programs, use the -cp command line option, e.g.

java -cp postgresql-9.4-1200.jdbc4.jar -jar myprogram.jar

If you're using an application server or servlet container, follow the instructions for installing JDBC drivers for that server or container.

For users of IDEs like Eclipse, NetBeans, etc, you should simply add the driver JAR like any other JAR to use it in your program. To use it within the IDE its self (for database browsing etc) you should follow the IDE specific documentation on how to install JDBC drivers.

Using the driver

Java 6 and above do not need any special action to enable the driver - if it's on the classpath it is automatically detected and loaded by the JVM.

For Java 1.5 and below, use Class.forName or a system parameter. See the main documentation and the JDBC tutorial for details - take a look at "more information" below.

JDBC URL syntax

The driver recognises JDBC URLs of the form:

jdbc:postgresql:database

jdbc:postgresql://host/database

jdbc:postgresql://host:port/database

Also, you can supply both username and passwords as arguments, by appending them to the URL. e.g.:

jdbc:postgresql:database?user=me
jdbc:postgresql:database?user=me&password=mypass

Notes:

  • If you are connecting to localhost or 127.0.0.1 you can leave it out of the URL. i.e.: jdbc:postgresql://localhost/mydb can be replaced with jdbc:postgresql:mydb

  • The port defaults to 5432 if it's left out.

There are many options you can pass on the URL to control the driver's behaviour. See the full JDBC driver documentation for details.

More information

For more information see the the PgJDBC driver documentation and the JDBC tutorial.

Bug reports, patches and development

PgJDBC development is carried out on the PgJDBC mailing list and on GitHub.

Bug reports

For bug reports please post on pgsql-jdbc or add a GitHub issue. If you include additional unit tests demonstrating the issue, or self-contained runnable test case including SQL scripts etc that shows the problem, your report is likely to get more attention. Make sure you include appropriate details on your environment, like your JDK version, container/appserver if any, platform, PostgreSQL version, etc. Err on the site of excess detail if in doubt.

Bug fixes and new features

If you've developed a patch you want to propose for inclusion in PgJDBC, feel free to send a GitHub pull request or post the patch on the PgJDBC mailing list. Make sure your patch includes additional unit tests demonstrating and testing any new features. In the case of bug fixes, where possible include a new unit test that failed before the fix and passes after it.

For information on working with GitHub, see: http://help.github.com/articles/fork-a-repo and http://learn.github.com/p/intro.html.

Testing

Remember to test proposed PgJDBC patches when running against older PostgreSQL versions where possible, not just against the PostgreSQL you use yourself.

You also need to test your changes with older JDKs. PgJDBC must support JDK5 ("Java 1.5") and newer, which means you can't use annotations, auto-boxing, for (:), and numerous other features added since JDK 5. Code that's JDBC4 specific may use JDK6 features, and code that's JDBC4.1 specific may use JDK7 features. Common code and JDBC3 code needs to stick to Java 1.5.

Two different versions of PgJDBC can be built, the JDBC 3 and JDBC 4 drivers. The former may be built with JDK 5, while building JDBC4 requires JDK 6 or 7. The driver to build is auto-selected based on the JDK version used to run the build. The best way to test a proposed change with both the JDBC3 and JDBC4 drivers is to build and test with both JDK5 and JDK6 or 7.

You can get old JDK versions from the Oracle Java Archive.

Typically you can test against an old JDK with:

export JAVA_HOME=/path/to/jdk_1_5
export PATH=$JAVA_HOME/bin:$JAVA_HOME/jre/bin:
ant clean test

For information about the unit tests and how to run them, see org/postgresql/test/README

Ideas

If you have ideas or proposed changes, please post on the mailing list. Think about how the change would affect other users, what side effects it might have, how practical it is to implement, what implications it would have for standards compliance and security, etc.

Few of the PgJDBC developers have much spare time, so it's unlikely that your idea will be picked up and implemented for you. The best way to make sure a desired feature or improvement happens is to implement it yourself. The PgJDBC sources are reasonably clear and they're pure Java, so it's sometimes easier than you might expect.

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Postgresql JDBC Driver

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