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$Header: /cvsroot/pgsql/doc/src/sgml/Attic/jdbc.sgml,v 1.39 2002/10/01 04:09:13 barry Exp $

$Header: /cvsroot/pgsql/doc/src/sgml/Attic/jdbc.sgml,v 1.40 2002/11/11 07:31:28 barry Exp $

-->

<chapter id="jdbc">

conn.setAutoCommit(false);

// Get the Large Object Manager to perform operations with

LargeObjectManager lobj = ((org.postgresql.Connection)conn).getLargeObjectAPI();

LargeObjectManager lobj = ((org.postgresql.PGConnection)conn).getLargeObjectAPI();

//create a new large object

int oid = lobj.create(LargeObjectManager.READ | LargeObjectManager.WRITE);

conn.setAutoCommit(false);

// Get the Large Object Manager to perform operations with

LargeObjectManager lobj = ((org.postgresql.Connection)conn).getLargeObjectAPI();

LargeObjectManager lobj = ((org.postgresql.PGConnection)conn).getLargeObjectAPI();

PreparedStatement ps = con.prepareStatement("SELECT imgOID FROM imagesLO WHERE imgname=?");

ps.setString(1, "myimage.gif");

<para>

To access some of the extensions, you need to use some extra

methods in the <classname>org.postgresql.Connection</classname>

methods in the <classname>org.postgresql.PGConnection</classname>

class. In this case, you would need to case the return value of

<function>Driver.getConnection()</function>. For example:

<programlisting>

Connection db = Driver.getConnection(url, username, password);

// ...

// later on

Fastpath fp = ((org.postgresql.Connection)db).getFastpathAPI();

Fastpath fp = ((org.postgresql.PGConnection)db).getFastpathAPI();

</programlisting>

</para>

<sect3>

<title>Class <classname>org.postgresql.Connection</classname></title>

<title>Class <classname>org.postgresql.PGConnection</classname></title>

<synopsis>

public class Connection extends Object implements Connection

java.lang.Object

|

+----org.postgresql.Connection

public class PGConnection

</synopsis>

<para>

These are the extra methods used to gain access to

<productname>PostgreSQL</productname>'s extensions. Methods

defined by <classname>java.sql.Connection</classname> are not

listed.

<productname>PostgreSQL</productname>'s extensions.

</para>

<sect4>

<programlisting>

import org.postgresql.fastpath.*;

...

Fastpath fp = ((org.postgresql.Connection)myconn).getFastpathAPI();

Fastpath fp = ((org.postgresql.PGConnection)myconn).getFastpathAPI();

</programlisting>

where <varname>myconn</> is an open <classname>Connection</> to <productname>PostgreSQL</productname>.

</para>

<programlisting>

import org.postgresql.largeobject.*;

...

LargeObjectManager lo = ((org.postgresql.Connection)myconn).getLargeObjectAPI();

LargeObjectManager lo = ((org.postgresql.PGConnection)myconn).getLargeObjectAPI();

</programlisting>

where <varname>myconn</> is an open <classname>Connection</> to

<productname>PostgreSQL</productname>.

The best way to use this is as follows:

<programlisting>

...

((org.postgresql.Connection)myconn).addDataType("mytype","my.class.name");

((org.postgresql.PGConnection)myconn).addDataType("mytype","my.class.name");

...

</programlisting>

where <varname>myconn</varname> is an open <classname>Connection</> to

Then, in your code, you need to get a

<classname>FastPath</classname> object:

<programlisting>

Fastpath fp = ((org.postgresql.Connection)conn).getFastpathAPI();

Fastpath fp = ((org.postgresql.PGConnection)conn).getFastpathAPI();

</programlisting>

This will return an instance associated with the database

connection that you can use to issue commands. The casing of

<classname>Connection</classname> to

<classname>org.postgresql.Connection</classname> is required, as

<classname>org.postgresql.PGConnection</classname> is required, as

the <function>getFastpathAPI()</function> is an extension method,

not part of <acronym>JDBC</acronym>. Once you have a

<classname>Fastpath</classname> instance, you can use the

</para>

<para>

This class can only be created by org.postgresql.Connection. To

This class can only be created by org.postgresql.PGConnection. To

get access to this class, use the following segment of code:

<programlisting>

import org.postgresql.largeobject.*;

Connection conn;

LargeObjectManager lobj;

// ... code that opens a connection ...

lobj = ((org.postgresql.Connection)myconn).getLargeObjectAPI();

lobj = ((org.postgresql.PGConnection)myconn).getLargeObjectAPI();

</programlisting>

</para>