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Improve discussion of %TYPE and %ROWTYPE.

This commit is contained in:
Tom Lane 2001-05-11 06:10:44 +00:00
parent 1c1eb0fa0e
commit 0ad9abe72e
1 changed files with 18 additions and 16 deletions
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34
doc/src/sgml/plsql.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/Attic/plsql.sgml,v 2.29 2001/05/08 02:53:24 tgl Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/Attic/plsql.sgml,v 2.30 2001/05/11 06:10:44 tgl Exp $
-->
<chapter id="plpgsql">
@ -396,12 +396,13 @@ user_id CONSTANT INTEGER := 10;
</sect3>
<sect3 id="plpgsql-description-passed-vars">
<title>Variables Passed to Functions</title>
<title>Parameters Passed to Functions</title>
<para>
Variables passed to functions are named with the identifiers
Parameters passed to functions are named with the identifiers
<literal>$1</literal>, <literal>$2</literal>,
etc. (maximum is 16). Some examples:
etc. Optionally, aliases can be declared for the <literal>$n</literal>
parameter names for increased readability. Some examples:
<programlisting>
CREATE FUNCTION sales_tax(REAL) RETURNS REAL AS '
DECLARE
@ -437,7 +438,7 @@ END;
<variablelist>
<varlistentry>
<term>
%TYPE
<replaceable>variable</replaceable>%TYPE
</term>
<listitem>
<para>
@ -447,9 +448,9 @@ END;
values. For example, let's say you have a column
named <type>user_id</type> in your
<type>users</type> table. To declare a variable with
the same datatype as users you do:
the same datatype as users.user_id you write:
<programlisting>
user_id users.user_id%TYPE;
user_id users.user_id%TYPE;
</programlisting>
</para>
@ -467,30 +468,31 @@ user_id users.user_id%TYPE;
<varlistentry>
<term>
<replaceable>name</replaceable> <replaceable>table</replaceable>%ROWTYPE;
<replaceable>table</replaceable>%ROWTYPE
</term>
<listitem>
<para>
Declares a row with the structure of the given
table. <replaceable>table</replaceable> must be an existing
<type>%ROWTYPE</type> provides the composite datatype corresponding
to a whole row of the specified table.
<replaceable>table</replaceable> must be an existing
table or view name of the database. The fields of the row are
accessed in the dot notation. Parameters to a function can be
composite types (complete table rows). In that case, the
corresponding identifier $n will be a rowtype, but it must be
aliased using the ALIAS command described above.
corresponding identifier $n will be a rowtype, and fields can
be selected from it, for example <literal>$1.user_id</literal>.
</para>
<para>
Only the user attributes of a table row are accessible in the
row, no OID or other system attributes (because the row could
be from a view). The fields of the rowtype inherit the
Only the user-defined attributes of a table row are accessible in a
rowtype variable, not OID or other system attributes (because the
row could be from a view). The fields of the rowtype inherit the
table's field sizes or precision for <type>char()</type>
etc. data types.
</para>
<programlisting>
DECLARE
users_rec users%ROWTYPE;
user_id users%TYPE;
user_id users.user_id%TYPE;
BEGIN
user_id := users_rec.user_id;
...