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>PostgreSQL 7.4.1 Documentation</TH
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><DIV
CLASS="CHAPTER"
><H1
><A
NAME="JDBC"
></A
>Chapter 31. <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> Interface</H1
><DIV
CLASS="TOC"
><DL
><DT
><B
>Table of Contents</B
></DT
><DT
>31.1. <A
HREF="jdbc.html#JDBC-SETUP"
>Setting up the <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> Driver</A
></DT
><DD
><DL
><DT
>31.1.1. <A
HREF="jdbc.html#JDBC-BUILD"
>Getting the Driver</A
></DT
><DT
>31.1.2. <A
HREF="jdbc.html#JDBC-CLASSPATH"
>Setting up the Class Path</A
></DT
><DT
>31.1.3. <A
HREF="jdbc.html#JDBC-PREPARE"
>Preparing the Database Server for <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
></A
></DT
></DL
></DD
><DT
>31.2. <A
HREF="jdbc-use.html"
>Initializing the Driver</A
></DT
><DD
><DL
><DT
>31.2.1. <A
HREF="jdbc-use.html#JDBC-IMPORT"
>Importing <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
></A
></DT
><DT
>31.2.2. <A
HREF="jdbc-use.html#JDBC-LOAD"
>Loading the Driver</A
></DT
><DT
>31.2.3. <A
HREF="jdbc-use.html#JDBC-CONNECT"
>Connecting to the Database</A
></DT
><DT
>31.2.4. <A
HREF="jdbc-use.html#JDBC-DISCONNECT"
>Closing the Connection</A
></DT
></DL
></DD
><DT
>31.3. <A
HREF="jdbc-query.html"
>Issuing a Query and Processing the Result</A
></DT
><DD
><DL
><DT
>31.3.1. <A
HREF="jdbc-query.html#JDBC-QUERY-WITH-CURSOR"
>Getting results based on a cursor</A
></DT
><DT
>31.3.2. <A
HREF="jdbc-query.html#AEN24307"
>Using the <CODE
CLASS="CLASSNAME"
>Statement</CODE
> or <CODE
CLASS="CLASSNAME"
>PreparedStatement</CODE
> Interface</A
></DT
><DT
>31.3.3. <A
HREF="jdbc-query.html#AEN24333"
>Using the <CODE
CLASS="CLASSNAME"
>ResultSet</CODE
> Interface</A
></DT
></DL
></DD
><DT
>31.4. <A
HREF="jdbc-update.html"
>Performing Updates</A
></DT
><DT
>31.5. <A
HREF="jdbc-callproc.html"
>Calling Stored Functions</A
></DT
><DD
><DL
><DT
>31.5.1. <A
HREF="jdbc-callproc.html#AEN24386"
>Using the <CODE
CLASS="CLASSNAME"
>CallableStatement</CODE
> Interface</A
></DT
><DT
>31.5.2. <A
HREF="jdbc-callproc.html#AEN24396"
>Obtaining <CODE
CLASS="CLASSNAME"
>ResultSet</CODE
> from a stored function</A
></DT
></DL
></DD
><DT
>31.6. <A
HREF="jdbc-ddl.html"
>Creating and Modifying Database Objects</A
></DT
><DT
>31.7. <A
HREF="jdbc-binary-data.html"
>Storing Binary Data</A
></DT
><DT
>31.8. <A
HREF="jdbc-ext.html"
><SPAN
CLASS="APPLICATION"
>PostgreSQL</SPAN
> Extensions to the
<ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> <ACRONYM
CLASS="ACRONYM"
>API</ACRONYM
></A
></DT
><DD
><DL
><DT
>31.8.1. <A
HREF="jdbc-ext.html#AEN24522"
>Accessing the Extensions</A
></DT
><DT
>31.8.2. <A
HREF="jdbc-ext.html#AEN24770"
>Geometric Data Types</A
></DT
><DT
>31.8.3. <A
HREF="jdbc-ext.html#AEN24799"
>Large Objects</A
></DT
></DL
></DD
><DT
>31.9. <A
HREF="jdbc-thread.html"
>Using the Driver in a Multithreaded or a Servlet Environment</A
></DT
><DT
>31.10. <A
HREF="jdbc-datasource.html"
>Connection Pools and Data Sources</A
></DT
><DD
><DL
><DT
>31.10.1. <A
HREF="jdbc-datasource.html#JDBC-DS-INTRO"
>Overview</A
></DT
><DT
>31.10.2. <A
HREF="jdbc-datasource.html#JDBC-DS-CPDS"
>Application Servers: <CODE
CLASS="CLASSNAME"
>ConnectionPoolDataSource</CODE
></A
></DT
><DT
>31.10.3. <A
HREF="jdbc-datasource.html#JDBC-DS-DS"
>Applications: <CODE
CLASS="CLASSNAME"
>DataSource</CODE
></A
></DT
><DT
>31.10.4. <A
HREF="jdbc-datasource.html#JDBC-JNDI"
>Data Sources and <ACRONYM
CLASS="ACRONYM"
>JNDI</ACRONYM
></A
></DT
></DL
></DD
><DT
>31.11. <A
HREF="jdbc-reading.html"
>Further Reading</A
></DT
></DL
></DIV
><A
NAME="AEN24099"
></A
><A
NAME="AEN24101"
></A
><P
> <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> is a core <ACRONYM
CLASS="ACRONYM"
>API</ACRONYM
> of Java 1.1 and later.
It provides a standard set of
interfaces to <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
>-compliant databases.
</P
><P
> <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> provides a <I
CLASS="FIRSTTERM"
>type
4</I
> <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> driver. Type 4 indicates
that the driver is written in Pure Java, and communicates in the
database system's own network protocol. Because of this, the driver
is platform independent; once compiled, the driver can be used on
any system.
</P
><P
> This chapter is not intended as a complete guide to
<ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> programming, but should help to get you
started. For more information refer to the standard
<ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> <ACRONYM
CLASS="ACRONYM"
>API</ACRONYM
> documentation.
Also, take a look at the examples included with the source.
</P
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="JDBC-SETUP"
>31.1. Setting up the <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> Driver</A
></H1
><P
> This section describes the steps you need to take before you can
write or run programs that use the <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> interface.
</P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="JDBC-BUILD"
>31.1.1. Getting the Driver</A
></H2
><P
> Precompiled versions of the driver can be downloaded from
the <A
HREF="http://jdbc.postgresql.org"
TARGET="_top"
><SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
<ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> web site</A
>.
</P
><P
> Alternatively you can build the driver from source, but you should
only need to do this if you are making changes to the source code.
For details, refer to the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
<A
HREF="installation.html"
>installation instructions</A
>.
After installation, the driver should be found in
<TT
CLASS="FILENAME"
><VAR
CLASS="REPLACEABLE"
>PREFIX</VAR
>/share/java/postgresql.jar</TT
>.
The resulting driver will be built for the version of Java you are
running. If you build with a 1.1 <ACRONYM
CLASS="ACRONYM"
>JDK</ACRONYM
> you will build a
version that supports the <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> 1 specification, if you build
with a 1.2 or 1.3 <ACRONYM
CLASS="ACRONYM"
>JDK</ACRONYM
> you will build a version that supports
the <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> 2 specification, and finally if you build with a
1.4 <ACRONYM
CLASS="ACRONYM"
>JDK</ACRONYM
> you will build a version that supports the
<ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> 3 specification.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="JDBC-CLASSPATH"
>31.1.2. Setting up the Class Path</A
></H2
><A
NAME="AEN24139"
></A
><A
NAME="AEN24141"
></A
><P
> To use the driver, the JAR archive (named
<TT
CLASS="FILENAME"
>postgresql.jar</TT
> if you built from source, otherwise
it will likely be named <TT
CLASS="FILENAME"
>pg7.4jdbc1.jar</TT
>,
<TT
CLASS="FILENAME"
>pg7.4jdbc2.jar</TT
>, or
<TT
CLASS="FILENAME"
>pg7.4jdbc3.jar</TT
> for the <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> 1,
<ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> 2, and <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> 3 versions respectively)
needs to be included in the class path, either by putting it in the
<TT
CLASS="ENVAR"
>CLASSPATH</TT
> environment variable, or by using flags on the
<TT
CLASS="COMMAND"
>java</TT
> command line.
</P
><P
> For instance, assume we have an application that uses the
<ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> driver to access a database, and that
application is installed as
<TT
CLASS="FILENAME"
>/usr/local/lib/myapp.jar</TT
>. The PostgreSQL
<ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> driver installed as
<TT
CLASS="FILENAME"
>/usr/local/pgsql/share/java/postgresql.jar</TT
>. To run
the application, we would use:
</P><PRE
CLASS="PROGRAMLISTING"
>export CLASSPATH=/usr/local/lib/myapp.jar:/usr/local/pgsql/share/java/postgresql.jar:.
java MyApp</PRE
><P>
</P
><P
> Loading the driver from within the application is covered in
<A
HREF="jdbc-use.html"
>Section 31.2</A
>.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="JDBC-PREPARE"
>31.1.3. Preparing the Database Server for <ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
></A
></H2
><P
> Because Java only uses TCP/IP connections, the
<SPAN
CLASS="APPLICATION"
>PostgreSQL</SPAN
> server must be configured to
accept TCP/IP connections. This can be done by setting
<TT
CLASS="LITERAL"
>tcpip_socket = true</TT
> in the
<TT
CLASS="FILENAME"
>postgresql.conf</TT
> file or by supplying the
<VAR
CLASS="OPTION"
>-i</VAR
> option flag when starting
<TT
CLASS="COMMAND"
>postmaster</TT
>.
</P
><P
> Also, the client authentication setup in the
<TT
CLASS="FILENAME"
>pg_hba.conf</TT
> file may need to be configured.
Refer to <A
HREF="client-authentication.html"
>Chapter 19</A
> for details. The
<ACRONYM
CLASS="ACRONYM"
>JDBC</ACRONYM
> driver supports the <TT
CLASS="LITERAL"
>trust</TT
>,
<TT
CLASS="LITERAL"
>ident</TT
>, <TT
CLASS="LITERAL"
>password</TT
>, <TT
CLASS="LITERAL"
>md5</TT
>, and
<TT
CLASS="LITERAL"
>crypt</TT
> authentication methods.
</P
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