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<chapter id="plpgsql">

<para>

The <literal>show errors</literal> command does not exist in

<productname>PostgreSQL</>, and is not needed since errors are

reported automatically.

reported automatically.

</para>

</listitem>

</itemizedlist>

<para>

The exception names supported by <application>PL/pgSQL</> are

different from Oracle's. The set of built-in exception names

is much larger (see <xref linkend="errcodes-appendix">).

is much larger (see <xref linkend="errcodes-appendix">). There

is not currently a way to declare user-defined exception names.

</para>

</callout>

</calloutlist>

<productname>PostgreSQL</productname>.

</para>

<sect3 id="plpgsql-porting-exceptions">

<title>Implicit Rollback after Exceptions</title>

<para>

In <application>PL/pgSQL</>, when an exception is caught by an

<literal>EXCEPTION</> clause, all database changes since the block's

<literal>BEGIN</> are automatically rolled back. That is, the behavior

is equivalent to what you'd get in Oracle with

<programlisting>

BEGIN

SAVEPOINT s1;

... code here ...

EXCEPTION

WHEN ... THEN

ROLLBACK TO s1;

... code here ...

WHEN ... THEN

ROLLBACK TO s1;

... code here ...

END;

</programlisting>

If you are translating an Oracle procedure that uses

<command>SAVEPOINT</> and <command>ROLLBACK TO</> in this style,

your task is easy: just omit the <command>SAVEPOINT</> and

<command>ROLLBACK TO</>. If you have a procedure that uses

<command>SAVEPOINT</> and <command>ROLLBACK TO</> in a different way

then some actual thought will be required.

</para>

</sect3>

<sect3>

<title><command>EXECUTE</command></title>