diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/catalogs.sgml | 5 | ||||
| -rw-r--r-- | doc/src/sgml/func.sgml | 28 | ||||
| -rw-r--r-- | doc/src/sgml/plpgsql.sgml | 21 | ||||
| -rw-r--r-- | doc/src/sgml/ref/create_function.sgml | 48 | ||||
| -rw-r--r-- | doc/src/sgml/xfunc.sgml | 79 |
5 files changed, 154 insertions, 27 deletions
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 83be70ca666..a7a3cea9068 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.170 2008/07/16 16:55:23 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.171 2008/07/18 03:32:51 tgl Exp $ --> <!-- Documentation of the system catalogs, directed toward PostgreSQL developers --> @@ -3680,7 +3680,8 @@ <literal>i</literal> for <literal>IN</> arguments, <literal>o</literal> for <literal>OUT</> arguments, <literal>b</literal> for <literal>INOUT</> arguments, - <literal>v</literal> for <literal>VARIADIC</> arguments. + <literal>v</literal> for <literal>VARIADIC</> arguments, + <literal>t</literal> for <literal>TABLE</> arguments. If all the arguments are <literal>IN</literal> arguments, this field will be null. Note that subscripts correspond to positions of diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index acd2b92918e..fb77ae43ea4 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.441 2008/07/16 00:48:53 momjian Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.442 2008/07/18 03:32:51 tgl Exp $ --> <chapter id="functions"> <title>Functions and Operators</title> @@ -11564,6 +11564,14 @@ SELECT pg_type_is_visible('myschema.widget'::regtype); </indexterm> <indexterm> + <primary>pg_get_function_arguments</primary> + </indexterm> + + <indexterm> + <primary>pg_get_function_result</primary> + </indexterm> + + <indexterm> <primary>pg_get_indexdef</primary> </indexterm> @@ -11637,6 +11645,16 @@ SELECT pg_type_is_visible('myschema.widget'::regtype); in it refer to the relation indicated by the second parameter</entry> </row> <row> + <entry><literal><function>pg_get_function_arguments</function>(<parameter>func_oid</parameter>)</literal></entry> + <entry><type>text</type></entry> + <entry>get argument list for function</entry> + </row> + <row> + <entry><literal><function>pg_get_function_result</function>(<parameter>func_oid</parameter>)</literal></entry> + <entry><type>text</type></entry> + <entry>get <literal>RETURNS</> clause for function</entry> + </row> + <row> <entry><literal><function>pg_get_indexdef</function>(<parameter>index_oid</parameter>)</literal></entry> <entry><type>text</type></entry> <entry>get <command>CREATE INDEX</> command for index</entry> @@ -11739,6 +11757,14 @@ SELECT pg_type_is_visible('myschema.widget'::regtype); </para> <para> + <function>pg_get_function_arguments</function> returns the argument list + of a function, in the form it would need to appear in within + <command>CREATE FUNCTION</>. + <function>pg_get_function_result</function> similarly returns the + appropriate <literal>RETURNS</> clause for the function. + </para> + + <para> <function>pg_get_serial_sequence</function> returns the name of the sequence associated with a column, or NULL if no sequence is associated with the column. The first input parameter is a table name with diff --git a/doc/src/sgml/plpgsql.sgml b/doc/src/sgml/plpgsql.sgml index 42bd6048b68..e47142078c0 100644 --- a/doc/src/sgml/plpgsql.sgml +++ b/doc/src/sgml/plpgsql.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.132 2008/07/16 01:30:21 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/plpgsql.sgml,v 1.133 2008/07/18 03:32:51 tgl Exp $ --> <chapter id="plpgsql"> <title><application>PL/pgSQL</application> - <acronym>SQL</acronym> Procedural Language</title> @@ -157,6 +157,8 @@ parameters in place of an explicit specification of the return type. This does not add any fundamental capability to the language, but it is often convenient, especially for returning multiple values. + The <literal>RETURNS TABLE</> notation can also be used in place + of <literal>RETURNS SETOF</>. </para> <para> @@ -469,6 +471,23 @@ $$ LANGUAGE plpgsql; </para> <para> + Another way to declare a <application>PL/pgSQL</application> function + is with <literal>RETURNS TABLE</>, for example: + +<programlisting> +CREATE FUNCTION extended_sales(p_itemno int) RETURNS TABLE(quantity int, total numeric) AS $$ +BEGIN + RETURN QUERY SELECT quantity, quantity * price FROM sales WHERE itemno = p_itemno; +END; +$$ LANGUAGE plpgsql; +</programlisting> + + This is exactly equivalent to declaring one or more <literal>OUT</> + parameters and specifying <literal>RETURNS SETOF + <replaceable>sometype</></literal>. + </para> + + <para> When the return type of a <application>PL/pgSQL</application> function is declared as a polymorphic type (<type>anyelement</type>, <type>anyarray</type>, <type>anynonarray</type>, or <type>anyenum</>), diff --git a/doc/src/sgml/ref/create_function.sgml b/doc/src/sgml/ref/create_function.sgml index 18b9bf7beea..b6f9c015c55 100644 --- a/doc/src/sgml/ref/create_function.sgml +++ b/doc/src/sgml/ref/create_function.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.79 2008/07/16 01:30:21 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.80 2008/07/18 03:32:52 tgl Exp $ --> <refentry id="SQL-CREATEFUNCTION"> @@ -21,7 +21,8 @@ $PostgreSQL: pgsql/doc/src/sgml/ref/create_function.sgml,v 1.79 2008/07/16 01:30 <synopsis> CREATE [ OR REPLACE ] FUNCTION <replaceable class="parameter">name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">argtype</replaceable> [, ...] ] ) - [ RETURNS <replaceable class="parameter">rettype</replaceable> ] + [ RETURNS <replaceable class="parameter">rettype</replaceable> + | RETURNS TABLE ( <replaceable class="parameter">colname</replaceable> <replaceable class="parameter">coltype</replaceable> [, ...] ) ] { LANGUAGE <replaceable class="parameter">langname</replaceable> | IMMUTABLE | STABLE | VOLATILE | CALLED ON NULL INPUT | RETURNS NULL ON NULL INPUT | STRICT @@ -49,7 +50,7 @@ CREATE [ OR REPLACE ] FUNCTION If a schema name is included, then the function is created in the specified schema. Otherwise it is created in the current schema. The name of the new function must not match any existing function - with the same argument types in the same schema. However, + with the same input argument types in the same schema. However, functions of different argument types can share a name (this is called <firstterm>overloading</>). </para> @@ -104,6 +105,9 @@ CREATE [ OR REPLACE ] FUNCTION The mode of an argument: <literal>IN</>, <literal>OUT</>, <literal>INOUT</>, or <literal>VARIADIC</>. If omitted, the default is <literal>IN</>. + Only <literal>OUT</> arguments can follow a <literal>VARIADIC</> one. + Also, <literal>OUT</> and <literal>INOUT</> arguments cannot be used + together with the <literal>RETURNS TABLE</> notation. </para> </listitem> </varlistentry> @@ -184,6 +188,30 @@ CREATE [ OR REPLACE ] FUNCTION </varlistentry> <varlistentry> + <term><replaceable class="parameter">colname</replaceable></term> + + <listitem> + <para> + The name of an output column in the <literal>RETURNS TABLE</> + syntax. This is effectively another way of declaring a named + <literal>OUT</> parameter, except that <literal>RETURNS TABLE</> + also implies <literal>RETURNS SETOF</>. + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><replaceable class="parameter">coltype</replaceable></term> + + <listitem> + <para> + The data type of an output column in the <literal>RETURNS TABLE</> + syntax. + </para> + </listitem> + </varlistentry> + + <varlistentry> <term><replaceable class="parameter">langname</replaceable></term> <listitem> @@ -437,7 +465,7 @@ CREATE [ OR REPLACE ] FUNCTION <productname>PostgreSQL</productname> allows function <firstterm>overloading</firstterm>; that is, the same name can be used for several different functions so long as they have distinct - argument types. However, the C names of all functions must be + input argument types. However, the C names of all functions must be different, so you must give overloaded C functions different C names (for example, use the argument types as part of the C names). @@ -541,6 +569,18 @@ CREATE FUNCTION dup(int) RETURNS dup_result SELECT * FROM dup(42); </programlisting> + Another way to return multiple columns is to use a <literal>TABLE</> + function: +<programlisting> +CREATE FUNCTION dup(int) RETURNS TABLE(f1 int, f2 text) + AS $$ SELECT $1, CAST($1 AS text) || ' is text' $$ + LANGUAGE SQL; + +SELECT * FROM dup(42); +</programlisting> + However, a <literal>TABLE</> function is different from the + preceding examples, because it actually returns a <emphasis>set</> + of records, not just one record. </para> </refsect1> diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml index 55ed719ec64..26567334316 100644 --- a/doc/src/sgml/xfunc.sgml +++ b/doc/src/sgml/xfunc.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.131 2008/07/16 01:30:21 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.132 2008/07/18 03:32:52 tgl Exp $ --> <sect1 id="xfunc"> <title>User-Defined Functions</title> @@ -94,11 +94,12 @@ </para> <para> - <indexterm><primary>SETOF</><seealso>function</></> Alternatively, - an SQL function can be declared to return a set, by specifying the - function's return type as <literal>SETOF - <replaceable>sometype</></literal>. In this case all rows of the - last query's result are returned. Further details appear below. + Alternatively, an SQL function can be declared to return a set, + by specifying the function's return type as <literal>SETOF + <replaceable>sometype</></literal>, or equivalently by declaring it as + <literal>RETURNS TABLE(<replaceable>columns</>)</literal>. In this case + all rows of the last query's result are returned. Further details appear + below. </para> <para> @@ -117,7 +118,7 @@ other SQL commands. (The only exception is that you cannot put <command>BEGIN</>, <command>COMMIT</>, <command>ROLLBACK</>, or <command>SAVEPOINT</> commands into a <acronym>SQL</acronym> function.) - However, the final command + However, the final command must be a <command>SELECT</command> that returns whatever is specified as the function's return type. Alternatively, if you want to define a SQL function that performs actions but has no @@ -175,7 +176,7 @@ INSERT INTO $1 VALUES (42); <para> The simplest possible <acronym>SQL</acronym> function has no arguments and simply returns a base type, such as <type>integer</type>: - + <screen> CREATE FUNCTION one() RETURNS integer AS $$ SELECT 1 AS result; @@ -202,7 +203,7 @@ SELECT one(); </para> <para> - It is almost as easy to define <acronym>SQL</acronym> functions + It is almost as easy to define <acronym>SQL</acronym> functions that take base types as arguments. In the example below, notice how we refer to the arguments within the function as <literal>$1</> and <literal>$2</>. @@ -226,7 +227,7 @@ SELECT add_em(1, 2) AS answer; <programlisting> CREATE FUNCTION tf1 (integer, numeric) RETURNS integer AS $$ - UPDATE bank + UPDATE bank SET balance = balance - $2 WHERE accountno = $1; SELECT 1; @@ -248,7 +249,7 @@ SELECT tf1(17, 100.0); <programlisting> CREATE FUNCTION tf1 (integer, numeric) RETURNS numeric AS $$ - UPDATE bank + UPDATE bank SET balance = balance - $2 WHERE accountno = $1; SELECT balance FROM bank WHERE accountno = $1; @@ -267,7 +268,7 @@ $$ LANGUAGE SQL; types, we must not only specify which argument we want (as we did above with <literal>$1</> and <literal>$2</literal>) but also the desired attribute (field) of that argument. For example, - suppose that + suppose that <type>emp</type> is a table containing employee data, and therefore also the name of the composite type of each row of the table. Here is a function <function>double_salary</function> that computes what someone's @@ -323,7 +324,7 @@ SELECT name, double_salary(ROW(name, salary*1.1, age, cubicle)) AS dream <para> It is also possible to build a function that returns a composite type. - This is an example of a function + This is an example of a function that returns a single <type>emp</type> row: <programlisting> @@ -364,7 +365,7 @@ ERROR: function declared to return emp returns varchar instead of text at colum </para> </listitem> </itemizedlist> - </para> + </para> <para> A different way to define the same function is: @@ -380,7 +381,7 @@ $$ LANGUAGE SQL; in this situation, but it is a handy alternative in some cases — for example, if we need to compute the result by calling another function that returns the desired composite value. - </para> + </para> <para> We could call this function directly in either of two ways: @@ -401,7 +402,7 @@ SELECT * FROM new_emp(); The second way is described more fully in <xref linkend="xfunc-sql-table-functions">. - </para> + </para> <para> When you use a function that returns a composite type, @@ -429,7 +430,7 @@ LINE 1: SELECT new_emp().name; <para> Another option is to use - functional notation for extracting an attribute. The simple way + functional notation for extracting an attribute. The simple way to explain this is that we can use the notations <literal>attribute(table)</> and <literal>table.attribute</> interchangeably. @@ -693,9 +694,14 @@ SELECT *, upper(fooname) FROM getfoo(1) AS t1; </para> </sect2> - <sect2> + <sect2 id="xfunc-sql-functions-returning-set"> <title><acronym>SQL</acronym> Functions Returning Sets</title> + <indexterm> + <primary>function</primary> + <secondary>with SETOF</secondary> + </indexterm> + <para> When an SQL function is declared as returning <literal>SETOF <replaceable>sometype</></literal>, the function's final @@ -733,7 +739,7 @@ SELECT * FROM getfoo(1) AS t1; <programlisting> CREATE FUNCTION sum_n_product_with_tab (x int, OUT sum int, OUT product int) RETURNS SETOF record AS $$ - SELECT x + tab.y, x * tab.y FROM tab; + SELECT $1 + tab.y, $1 * tab.y FROM tab; $$ LANGUAGE SQL; </programlisting> @@ -794,6 +800,41 @@ SELECT name, listchildren(name) FROM nodes; </para> </sect2> + <sect2 id="xfunc-sql-functions-returning-table"> + <title><acronym>SQL</acronym> Functions Returning <literal>TABLE</></title> + + <indexterm> + <primary>function</primary> + <secondary>RETURNS TABLE</secondary> + </indexterm> + + <para> + There is another way to declare a function as returning a set, + which is to use the syntax + <literal>RETURNS TABLE(<replaceable>columns</>)</literal>. + This is equivalent to using one or more <literal>OUT</> parameters plus + marking the function as returning <literal>SETOF record</> (or + <literal>SETOF</> a single output parameter's type, as appropriate). + This notation is specified in recent versions of the SQL standard, and + thus may be more portable than using <literal>SETOF</>. + </para> + + <para> + For example, the preceding sum-and-product example could also be + done this way: + +<programlisting> +CREATE FUNCTION sum_n_product_with_tab (x int) RETURNS TABLE(sum int, product int) AS $$ + SELECT $1 + tab.y, $1 * tab.y FROM tab; +$$ LANGUAGE SQL; +</programlisting> + + It is not allowed to use explicit <literal>OUT</> or <literal>INOUT</> + parameters with the <literal>RETURNS TABLE</> notation — you must + put all the output columns in the <literal>TABLE</> list. + </para> + </sect2> + <sect2> <title>Polymorphic <acronym>SQL</acronym> Functions</title> |