From ff8d68df5c5060ef4e86b747d07bbc19a1edafb8 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Sun, 8 Aug 2004 01:48:31 +0000
Subject: [PATCH] Included is an example of using savepoints in a non-trivial
example.
Giving examples in the SQL command reference is hard because we don't
have conditionals at the SQL level.
Gavin Sherry
---
doc/src/sgml/ref/begin.sgml | 5 ++++-
doc/src/sgml/ref/update.sgml | 15 ++++++++++++++-
2 files changed, 18 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/ref/begin.sgml b/doc/src/sgml/ref/begin.sgml
index d40cb416bc5..bf1195f5277 100644
--- a/doc/src/sgml/ref/begin.sgml
+++ b/doc/src/sgml/ref/begin.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/begin.sgml,v 1.31 2004/08/01 17:32:13 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/begin.sgml,v 1.32 2004/08/08 01:48:31 momjian Exp $
PostgreSQL documentation
-->
@@ -100,6 +100,9 @@ BEGIN [ WORK | TRANSACTION ]
<para>
Issuing <command>BEGIN</> when already inside a transaction block will
provoke a warning message. The state of the transaction is not affected.
+ To nest transactions within a transaction block, use savepoints
+ (See <xref linkend="sql-start-transaction" endterm="sql-start-transaction-title">
+ for more information).
</para>
</refsect1>
diff --git a/doc/src/sgml/ref/update.sgml b/doc/src/sgml/ref/update.sgml
index 5695df1584b..48d160b2ece 100644
--- a/doc/src/sgml/ref/update.sgml
+++ b/doc/src/sgml/ref/update.sgml
@@ -1,5 +1,5 @@
<!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.29 2004/06/09 19:08:13 tgl Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/update.sgml,v 1.30 2004/08/08 01:48:31 momjian Exp $
PostgreSQL documentation
-->
@@ -187,6 +187,19 @@ UPDATE employees SET sales_count = sales_count + 1 FROM accounts
<programlisting>
UPDATE employees SET sales_count = sales_count + 1 WHERE id =
(SELECT sales_person FROM accounts WHERE name = 'Acme Corporation');
+</programlisting>
+
+ Attempt to insert a new stock item along with the quantity of stock. If
+ the item exists, update the stock count of the existing item. To do this,
+ use savepoints.
+<programlisting>
+BEGIN;
+SAVEPOINT sp1;
+INSERT INTO wines VALUES('Chateau Lafite 2003', '24');
+-- Check for unique violation on name
+ROLLBACK TO sp1;
+UPDATE wines SET stock = stock + 24 WHERE winename='Chateau Lafite 2003';
+COMMIT;
</programlisting>
</para>
</refsect1>
--
GitLab