diff options
Diffstat (limited to 'doc/src/sgml/ref/create_cast.sgml')
| -rw-r--r-- | doc/src/sgml/ref/create_cast.sgml | 41 |
1 files changed, 29 insertions, 12 deletions
diff --git a/doc/src/sgml/ref/create_cast.sgml b/doc/src/sgml/ref/create_cast.sgml index a76a417671e..b97135c9538 100644 --- a/doc/src/sgml/ref/create_cast.sgml +++ b/doc/src/sgml/ref/create_cast.sgml @@ -1,4 +1,4 @@ -<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/create_cast.sgml,v 1.10 2003/03/25 16:15:39 petere Exp $ --> +<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/create_cast.sgml,v 1.11 2003/04/22 10:08:08 petere Exp $ --> <refentry id="SQL-CREATECAST"> <refmeta> @@ -58,11 +58,11 @@ SELECT CAST(42 AS text); <para> If the cast is marked <literal>AS ASSIGNMENT</> then it can be invoked - implicitly when assigning to a column of the target data type. + implicitly when assigning a value to a column of the target data type. For example, supposing that <literal>foo.f1</literal> is a column of type <type>text</type>, then <programlisting> -INSERT INTO foo(f1) VALUES(42); +INSERT INTO foo (f1) VALUES (42); </programlisting> will be allowed if the cast from type <type>integer</type> to type <type>text</type> is marked <literal>AS ASSIGNMENT</>, otherwise @@ -75,7 +75,7 @@ INSERT INTO foo(f1) VALUES(42); If the cast is marked <literal>AS IMPLICIT</> then it can be invoked implicitly in any context, whether assignment or internally in an expression. For example, since <literal>||</> takes <type>text</> - arguments, + operands, <programlisting> SELECT 'The time is ' || now(); </programlisting> @@ -106,14 +106,16 @@ SELECT 'The time is ' || CAST(now() AS text); <para> To be able to create a cast, you must own the source or the target - data type. To create a binary-compatible cast, you must be superuser - (this restriction is made because an erroneous binary-compatible cast - conversion can easily crash the server). + data type. To create a binary-compatible cast, you must be superuser. + (This restriction is made because an erroneous binary-compatible cast + conversion can easily crash the server.) </para> + </refsect1> - <variablelist> - <title>Parameters</title> + <refsect1> + <title>Parameters</title> + <variablelist> <varlistentry> <term><replaceable>sourcetype</replaceable></term> @@ -183,6 +185,21 @@ SELECT 'The time is ' || CAST(now() AS text); </refsect1> + <refsect1> + <title>Diagnostics</title> + + <variablelist> + <varlistentry> + <term><computeroutput>CREATE CAST</computeroutput></term> + <listitem> + <para> + Message returned if the cast was successfully created. + </para> + </listitem> + </varlistentry> + </variablelist> + </refsect1> + <refsect1 id="sql-createcast-notes"> <title>Notes</title> @@ -201,8 +218,8 @@ SELECT 'The time is ' || CAST(now() AS text); argument of a different type was automatically a cast function. This convention has been abandoned in face of the introduction of schemas and to be able to represent binary compatible casts in the - catalogs. (The built-in cast functions still follow this naming - scheme, but they have to be shown as casts in <literal>pg_cast</> + system catalogs. (The built-in cast functions still follow this naming + scheme, but they have to be shown as casts in the system catalog <literal>pg_cast</> now.) </para> </refsect1> @@ -227,7 +244,7 @@ CREATE CAST (text AS int4) WITH FUNCTION int4(text); <para> The <command>CREATE CAST</command> command conforms to SQL99, - except that SQL99 does not make provisions for binary compatible + except that SQL99 does not make provisions for binary-compatible types. <literal>AS IMPLICIT</> is a <productname>PostgreSQL</productname> extension, too. </para> |