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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2004-08-08 22:40:46 +0000 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2004-08-08 22:40:46 +0000 |
| commit | 82fde1aaa818d50c758f596b170c38b592a9e53b (patch) | |
| tree | 5be05afccff523444ad18766b4dd9d1b5e3e9943 | |
| parent | 35a5fb68638e932db95b01e947885f9becb376fe (diff) | |
| download | postgresql-82fde1aaa818d50c758f596b170c38b592a9e53b.tar.gz postgresql-82fde1aaa818d50c758f596b170c38b592a9e53b.zip | |
Add note pointing out the difference in semantics between Oracle and
plpgsql EXCEPTION blocks.
| -rw-r--r-- | doc/src/sgml/plpgsql.sgml | 39 |
1 files changed, 36 insertions, 3 deletions
diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml index 06154407254..5e21d1abb68 100644 --- a/doc/src/sgml/plpgsql.sgml +++ b/doc/src/sgml/plpgsql.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.44 2004/08/08 00:50:58 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.45 2004/08/08 22:40:46 tgl Exp $ --> <chapter id="plpgsql"> @@ -2647,7 +2647,7 @@ show errors; <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> @@ -3009,7 +3009,8 @@ $$ LANGUAGE plpgsql; <para> The exception names supported by <application>PL/pgSQL</> are different from Oracle's. The set of built-in exception names - is much larger (see <xref linkend="errcodes-appendix">). + is much larger (see <xref linkend="errcodes-appendix">). There + is not currently a way to declare user-defined exception names. </para> </callout> </calloutlist> @@ -3032,6 +3033,38 @@ $$ LANGUAGE plpgsql; <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> |