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Diffstat (limited to 'doc/src/sgml/ref/create_function.sgml')
| -rw-r--r-- | doc/src/sgml/ref/create_function.sgml | 291 |
1 files changed, 146 insertions, 145 deletions
diff --git a/doc/src/sgml/ref/create_function.sgml b/doc/src/sgml/ref/create_function.sgml index 482393ec0ab..3dc37e3380d 100644 --- a/doc/src/sgml/ref/create_function.sgml +++ b/doc/src/sgml/ref/create_function.sgml @@ -1,173 +1,173 @@ -<REFENTRY ID="SQL-CREATEFUNCTION"> - <REFMETA> - <REFENTRYTITLE> +<refentry id="SQL-CREATEFUNCTION"> + <refmeta> + <refentrytitle> CREATE FUNCTION - </REFENTRYTITLE> - <REFMISCINFO>SQL - Language Statements</REFMISCINFO> - </REFMETA> - <REFNAMEDIV> - <REFNAME> + </refentrytitle> + <refmiscinfo>SQL - Language Statements</refmiscinfo> + </refmeta> + <refnamediv> + <refname> CREATE FUNCTION - </REFNAME> - <REFPURPOSE> + </refname> + <refpurpose> Defines a new function - </REFPURPOSE> + </refpurpose> </refnamediv> - <REFSYNOPSISDIV> - <REFSYNOPSISDIVINFO> - <DATE>1998-09-09</DATE> - </REFSYNOPSISDIVINFO> - <SYNOPSIS> + <refsynopsisdiv> + <refsynopsisdivinfo> + <date>1998-09-09</date> + </refsynopsisdivinfo> + <synopsis> CREATE FUNCTION <replaceable class="parameter">name</replaceable> ( [ <replaceable class="parameter">ftype</replaceable> [, ...] ] ) RETURNS <replaceable class="parameter">rtype</replaceable> AS <replaceable class="parameter">definition</replaceable> LANGUAGE '<replaceable class="parameter">langname</replaceable>' - </SYNOPSIS> + </synopsis> - <REFSECT2 ID="R2-SQL-CREATEFUNCTION-1"> - <REFSECT2INFO> - <DATE>1998-09-09</DATE> - </REFSECT2INFO> - <TITLE> + <refsect2 id="R2-SQL-CREATEFUNCTION-1"> + <refsect2info> + <date>1998-09-09</date> + </refsect2info> + <title> Inputs - </TITLE> - <PARA> - <VARIABLELIST> - <VARLISTENTRY> - <TERM> + </title> + <para> + <variablelist> + <varlistentry> + <term> <replaceable class="parameter">name</replaceable> - </TERM> - <LISTITEM> - <PARA> + </term> + <listitem> + <para> The name of a function to create. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> <replaceable class="parameter">ftype</replaceable> - </TERM> - <LISTITEM> - <PARA> + </term> + <listitem> + <para> The data type of function arguments. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> <replaceable class="parameter">rtype</replaceable> - </TERM> - <LISTITEM> - <PARA> + </term> + <listitem> + <para> The return data type. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> <replaceable class="parameter">definition</replaceable> - </TERM> - <LISTITEM> - <PARA> + </term> + <listitem> + <para> A string defining the function; the meaning depends on the language. It may be an internal function name, the path to an object file, an SQL query, or text in a procedural language. - </PARA> - </LISTITEM> - </VARLISTENTRY> - <VARLISTENTRY> - <TERM> + </para> + </listitem> + </varlistentry> + <varlistentry> + <term> <replaceable class="parameter">langname</replaceable> - </TERM> - <LISTITEM> - <PARA> + </term> + <listitem> + <para> may be '<literal>C</literal>', '<literal>sql</literal>', '<literal>internal</literal>' or '<replaceable class="parameter">plname</replaceable>', where '<replaceable class="parameter">plname</replaceable>' is the name of a created procedural language. See <command>CREATE LANGUAGE</command> for details. - </PARA> - </LISTITEM> - </VARLISTENTRY> + </para> + </listitem> + </varlistentry> </variablelist> </para> - </REFSECT2> + </refsect2> - <REFSECT2 ID="R2-SQL-CREATEFUNCTION-2"> - <REFSECT2INFO> - <DATE>1998-09-09</DATE> - </REFSECT2INFO> - <TITLE> + <refsect2 id="R2-SQL-CREATEFUNCTION-2"> + <refsect2info> + <date>1998-09-09</date> + </refsect2info> + <title> Outputs - </TITLE> - <PARA> + </title> + <para> - <VARIABLELIST> - <VARLISTENTRY> - <TERM> - <ReturnValue>CREATE</ReturnValue> - </TERM> - <LISTITEM> - <PARA> + <variablelist> + <varlistentry> + <term> + <returnvalue>CREATE</returnvalue> + </term> + <listitem> + <para> This is returned if the command completes successfully. </para> </listitem> </varlistentry> - </VARIABLELIST> + </variablelist> </para> - </REFSECT2> - </REFSYNOPSISDIV> + </refsect2> + </refsynopsisdiv> - <REFSECT1 ID="R1-SQL-CREATEFUNCTION-1"> - <REFSECT1INFO> - <DATE>1998-09-09</DATE> - </REFSECT1INFO> - <TITLE> + <refsect1 id="R1-SQL-CREATEFUNCTION-1"> + <refsect1info> + <date>1998-09-09</date> + </refsect1info> + <title> Description - </TITLE> - <PARA> + </title> + <para> <command>CREATE FUNCTION</command> allows a <productname>Postgres</productname> user to register a function with a database. Subsequently, this user is treated as the owner of the function. - </PARA> + </para> - <REFSECT2 ID="R2-SQL-CREATEFUNCTION-3"> - <REFSECT2INFO> - <DATE>1998-09-09</DATE> - </REFSECT2INFO> - <TITLE> + <refsect2 id="R2-SQL-CREATEFUNCTION-3"> + <refsect2info> + <date>1998-09-09</date> + </refsect2info> + <title> Notes - </TITLE> - <PARA> + </title> + <para> Refer to the chapter on functions in the <citetitle>PostgreSQL Programmer's Guide</citetitle> for further information. - </PARA> - <PARA> + </para> + <para> Use <command>DROP FUNCTION</command> to drop user-defined functions. - </PARA> + </para> - <PARA> + <para> <productname>Postgres</productname> allows function "overloading"; that is, the same name can be used for several different functions so long as they have distinct argument types. This facility must be used with caution for INTERNAL and C-language functions, however. - </PARA> + </para> - <PARA> + <para> Two INTERNAL functions cannot have the same C name without causing errors at link time. To get around that, give them different C names (for example, use the argument types as part of the C names), then specify those names in the AS clause of <command>CREATE FUNCTION</command>. If the AS clause is left empty then <command>CREATE FUNCTION</command> assumes the C name of the function is the same as the SQL name. - </PARA> + </para> - <PARA> + <para> For dynamically-loaded C functions, the SQL name of the function must be the same as the C function name, because the AS clause is used to give the path name of the object file containing the C code. In this @@ -178,18 +178,18 @@ in the <citetitle>PostgreSQL Programmer's Guide</citetitle> ways if there is a conflict of C function names. So, even if it works for you today, you might regret overloading names later when you try to run the code somewhere else. - </PARA> - </REFSECT2> + </para> + </refsect2> </refsect1> - <REFSECT1 ID="R1-SQL-CREATEFUNCTION-2"> - <TITLE> + <refsect1 id="R1-SQL-CREATEFUNCTION-2"> + <title> Usage - </TITLE> - <PARA> + </title> + <para> To create a simple SQL function: - </PARA> - <ProgramListing> + </para> + <programlisting> CREATE FUNCTION one() RETURNS int4 AS 'SELECT 1 AS RESULT' LANGUAGE 'sql'; @@ -201,7 +201,7 @@ in the <citetitle>PostgreSQL Programmer's Guide</citetitle> ------ 1 </computeroutput> - </ProgramListing> + </programlisting> <para> To create a C function, calling a routine from a user-created shared library. This particular routine calculates a check @@ -211,44 +211,44 @@ in the <citetitle>PostgreSQL Programmer's Guide</citetitle> <programlisting> <userinput> CREATE FUNCTION ean_checkdigit(bpchar, bpchar) RETURNS bool - AS '/usr1/proj/bray/sql/funcs.so' LANGUAGE 'c'; + AS '/usr1/proj/bray/sql/funcs.so' LANGUAGE 'c'; - CREATE TABLE product - ( - id char(8) PRIMARY KEY, - eanprefix char(8) CHECK (eanprefix ~ '[0-9]{2}-[0-9]{5}') - REFERENCES brandname(ean_prefix), - eancode char(6) CHECK (eancode ~ '[0-9]{6}'), - CONSTRAINT ean CHECK (ean_checkdigit(eanprefix, eancode)) - );</userinput> + CREATE TABLE product ( + id char(8) PRIMARY KEY, + eanprefix char(8) CHECK (eanprefix ~ '[0-9]{2}-[0-9]{5}') + REFERENCES brandname(ean_prefix), + eancode char(6) CHECK (eancode ~ '[0-9]{6}'), + CONSTRAINT ean CHECK (ean_checkdigit(eanprefix, eancode)) + ); + </userinput> </programlisting> - </REFSECT1> + </refsect1> - <REFSECT1 ID="R1-SQL-CREATEFUNCTION-3"> - <TITLE> + <refsect1 id="R1-SQL-CREATEFUNCTION-3"> + <title> Bugs - </TITLE> - <PARA> + </title> + <para> A C function cannot return a set of values. - </PARA> - </REFSECT1> + </para> + </refsect1> - <REFSECT1 ID="R1-SQL-CREATEFUNCTION-4"> - <TITLE> + <refsect1 id="R1-SQL-CREATEFUNCTION-4"> + <title> Compatibility - </TITLE> - <PARA> + </title> + <para> <command>CREATE FUNCTION</command> is a <productname>Postgres</productname> language extension. - </PARA> + </para> - <REFSECT2 ID="R2-SQL-CREATEFUNCTION-4"> - <REFSECT2INFO> - <DATE>1998-09-09</DATE> - </REFSECT2INFO> - <TITLE> + <refsect2 id="R2-SQL-CREATEFUNCTION-4"> + <refsect2info> + <date>1998-09-09</date> + </refsect2info> + <title> SQL/PSM - </TITLE> + </title> <para> <note> @@ -264,7 +264,8 @@ has not yet happened, but it is hoped that PSM will SQL/PSM <command>CREATE FUNCTION</command> has the following syntax: <synopsis> CREATE FUNCTION <replaceable class="parameter">name</replaceable> - ( [ [ IN | OUT | INOUT ] <replaceable class="parameter">parm</replaceable> <replaceable class="parameter">type</replaceable> [, ...] ] ) + ( [ [ IN | OUT | INOUT ] <replaceable class="parameter">eter</replaceable>eable> <replaceable + class="parameter">type</replaceable> [, ...] ] ) RETURNS <replaceable class="parameter">rtype</replaceable> LANGUAGE '<replaceable class="parameter">langname</replaceable>' ESPECIFIC <replaceable class="parameter">routine</replaceable> @@ -274,12 +275,12 @@ CREATE FUNCTION <replaceable class="parameter">name</replaceable> </para> </refsect2> </refsect1> -</REFENTRY> +</refentry> <!-- Keep this comment at the end of the file Local variables: mode: sgml -sgml-omittag:t +sgml-omittag:nil sgml-shorttag:t sgml-minimize-attributes:nil sgml-always-quote-attributes:t |