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Diffstat (limited to 'doc/src/sgml/dml.sgml')
| -rw-r--r-- | doc/src/sgml/dml.sgml | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/doc/src/sgml/dml.sgml b/doc/src/sgml/dml.sgml index 5bcec139756..788f4d7dacf 100644 --- a/doc/src/sgml/dml.sgml +++ b/doc/src/sgml/dml.sgml @@ -1,4 +1,4 @@ -<!-- $Header: /cvsroot/pgsql/doc/src/sgml/dml.sgml,v 1.1 2002/08/05 19:44:57 petere Exp $ --> +<!-- $Header: /cvsroot/pgsql/doc/src/sgml/dml.sgml,v 1.2 2002/10/20 05:05:46 tgl Exp $ --> <chapter id="dml"> <title>Data Manipulation</title> @@ -119,8 +119,8 @@ INSERT INTO products DEFAULT VALUES; necessarily possible to directly specify which row to update. Instead, you specify which conditions a row must meet in order to be updated. Only if you have a primary key in the table (no matter - whether you declared it or not) you can address rows individually - by choosing a condition that matches the primary key only. + whether you declared it or not) can you reliably address individual rows, + by choosing a condition that matches the primary key. Graphical database access tools rely on this fact to allow you to update rows individually. </para> @@ -195,5 +195,13 @@ UPDATE mytable SET a = 5, b = 3, c = 1 WHERE a > 0; DELETE FROM products WHERE price = 10; </programlisting> </para> + + <para> + If you simply write +<programlisting> +DELETE FROM products; +</programlisting> + then all rows in the table will be deleted! Caveat programmer. + </para> </sect1> </chapter> |