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Merge Tom and my descriptions of new sequence behavior into one entry.

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This commit is contained in:
Bruce Momjian 2005-10-03 02:21:16 +00:00
parent 07e74305fe
commit 4361e0d295
1 changed files with 19 additions and 30 deletions
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49
doc/src/sgml/release.sgml
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@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.382 2005/10/03 01:57:59 momjian Exp $
$PostgreSQL: pgsql/doc/src/sgml/release.sgml,v 1.383 2005/10/03 02:21:16 momjian Exp $
Typical markup:
@ -262,21 +262,6 @@ pg_[A-Za-z0-9_] <application>
<itemizedlist>
<listitem>
<para>
<varname>Add proper sequence function dependencies (Tom)
</para>
<para>
In previous releases, <function>nextval()</>,
<function>currval</>, and <function>setval()</> recorded
sequence names as simple text strings, meaning that renaming or
dropping a sequence used in a <command>DEFAULT</> made the
clause invalid. This release stores all newly-created sequence
function arguments using internal oids, allowing them to handle
sequence renaming, and adding dependency information that
</para>
</listitem>
<listitem>
<para>
<varname>add_missing_from</> is now false by default (Neil)
@ -408,22 +393,25 @@ pg_[A-Za-z0-9_] <application>
<listitem>
<para>
Sequence arguments of <function>nextval()</> and related functions
are now bound early by default (Tom)
<varname>Add proper sequence function dependencies for <command>
DEFAULT</> clauses (Tom)
</para>
<para>
When an expression like <literal>nextval('myseq')</> appears in a
column <command>DEFAULT</> expression or view, the referenced
sequence (here <literal>myseq</>) is now looked up immediately,
and its pg_class OID is placed in the stored expression. This
representation will survive renaming of the referenced sequence,
as well as changes in schema search paths. The system also
understands that the sequence reference represents a dependency,
so the sequence cannot be dropped without dropping the
referencing object. Previous releases stored this information as
a simple text string, with none of the benefits outlined above.
To get the old text-based behavior of run-time lookup of the
sequence name, cast the argument to <type>text</>, for example
In previous releases, <function>nextval()</>,
<function>currval</>, and <function>setval()</> recorded
sequence names as simple text strings, meaning that renaming or
dropping a sequence used in a <command>DEFAULT</> made the
clause invalid. This release stores all newly-created sequence
function arguments using internal OIDs, allowing them to handle
sequence renaming, and adding dependency information that
prevents improper sequence removal. It also makes
<command>DEFAULT</> clauses immune to schema search
path changes.
</para>
<para>
Some applications might rely on the old text-based behavior of
run-time lookup of the sequence name. This can still be done by
casting the argument to <type>text</>, for example
<literal>nextval('myseq'::text)</>.
</para>
<para>
@ -13495,3 +13483,4 @@ sgml-local-catalogs:("/usr/lib/sgml/catalog")
sgml-local-ecat-files:nil
End:
-->