diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/array.sgml | 7 | ||||
| -rw-r--r-- | doc/src/sgml/catalogs.sgml | 20 | ||||
| -rw-r--r-- | doc/src/sgml/ref/create_type.sgml | 38 | ||||
| -rw-r--r-- | doc/src/sgml/syntax.sgml | 6 |
4 files changed, 44 insertions, 27 deletions
diff --git a/doc/src/sgml/array.sgml b/doc/src/sgml/array.sgml index ec59d8e6a88..9646e1ab00f 100644 --- a/doc/src/sgml/array.sgml +++ b/doc/src/sgml/array.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/array.sgml,v 1.60 2007/04/06 19:22:38 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/array.sgml,v 1.61 2007/05/11 17:57:11 tgl Exp $ --> <sect1 id="arrays"> <title>Arrays</title> @@ -10,8 +10,9 @@ <para> <productname>PostgreSQL</productname> allows columns of a table to be defined as variable-length multidimensional arrays. Arrays of any - built-in or user-defined base type or enum type can be created. - (Arrays of composite types or domains are not yet supported, however.) + built-in or user-defined base type, enum type, or composite type + can be created. + Arrays of domains are not yet supported. </para> <sect2> diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index 8243dd8d046..2da4abc3407 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 2.150 2007/04/06 22:33:41 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.151 2007/05/11 17:57:11 tgl Exp $ --> <!-- Documentation of the system catalogs, directed toward PostgreSQL developers --> @@ -4525,6 +4525,17 @@ </row> <row> + <entry><structfield>typarray</structfield></entry> + <entry><type>oid</type></entry> + <entry><literal><link linkend="catalog-pg-type"><structname>pg_type</structname></link>.oid</literal></entry> + <entry> + If <structfield>typarray</structfield> is not 0 then it + identifies another row in <structname>pg_type</structname>, which + is the <quote>true</quote> array type having this type as element + </entry> + </row> + + <row> <entry><structfield>typinput</structfield></entry> <entry><type>regproc</type></entry> <entry><literal><link linkend="catalog-pg-proc"><structname>pg_proc</structname></link>.oid</literal></entry> @@ -4686,9 +4697,10 @@ <entry></entry> <entry><para> <structfield>typndims</structfield> is the number of array dimensions - for a domain that is an array (that is, <structfield>typbasetype</> is an array type; - the domain's <structfield>typelem</> will match the base type's <structfield>typelem</structfield>). - Zero for types other than array domains + for a domain that is an array (that is, <structfield>typbasetype</> is + an array type; the domain's <structfield>typelem</> will match the base + type's <structfield>typelem</structfield>). + Zero for types other than domains over array types </para></entry> </row> diff --git a/doc/src/sgml/ref/create_type.sgml b/doc/src/sgml/ref/create_type.sgml index 9be57d7fcde..08f4c1464c7 100644 --- a/doc/src/sgml/ref/create_type.sgml +++ b/doc/src/sgml/ref/create_type.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.69 2007/04/02 03:49:37 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.70 2007/05/11 17:57:11 tgl Exp $ PostgreSQL documentation --> @@ -312,15 +312,17 @@ CREATE TYPE <replaceable class="parameter">name</replaceable> <title>Array Types</title> <para> - Whenever a user-defined base or enum data type is created, + Whenever a user-defined type is created, <productname>PostgreSQL</productname> automatically creates an associated array type, whose name consists of the base type's - name prepended with an underscore. The parser understands this - naming convention, and translates requests for columns of type - <literal>foo[]</> into requests for type <literal>_foo</>. - The implicitly-created array type is variable length and uses the + name prepended with an underscore, and truncated if necessary to keep + it less than <symbol>NAMEDATALEN</symbol> bytes long. (If the name + so generated collides with an existing type name, the process is + repeated until a non-colliding name is found.) + This implicitly-created array type is variable length and uses the built-in input and output functions <literal>array_in</> and - <literal>array_out</>. + <literal>array_out</>. The array type tracks any changes in its + element type's owner or schema, and is dropped if the element type is. </para> <para> @@ -330,10 +332,9 @@ CREATE TYPE <replaceable class="parameter">name</replaceable> making a fixed-length type that happens to be internally an array of a number of identical things, and you want to allow these things to be accessed directly by subscripting, in addition to whatever operations you plan - to provide for the type as a whole. For example, type <type>name</> - allows its constituent <type>char</> elements to be accessed this way. - A 2-D <type>point</> type could allow its two component numbers to be - accessed like <literal>point[0]</> and <literal>point[1]</>. + to provide for the type as a whole. For example, type <type>point</> + is represented as just two floating-point numbers, which it allows to be + accessed as <literal>point[0]</> and <literal>point[1]</>. Note that this facility only works for fixed-length types whose internal form is exactly a sequence of identical fixed-length fields. A subscriptable @@ -529,12 +530,15 @@ CREATE TYPE <replaceable class="parameter">name</replaceable> <title>Notes</title> <para> - User-defined type names should not begin with the underscore character - (<literal>_</literal>) and should only be 62 characters - long (or in general <symbol>NAMEDATALEN</symbol> - 2, rather than - the <symbol>NAMEDATALEN</symbol> - 1 characters allowed for other - names). Type names beginning with underscore are reserved for - internally-created array type names. + It is best to avoid using type names that begin with the underscore + character (<literal>_</literal>). <productname>PostgreSQL</productname> + forms the name of an array type by prepending one or more underscores + to the element type's name, and these names may collide with user-defined + type names that begin with underscore. While the system will modify + generated array type names to avoid collisions, this does not help if the + conflicting array type already exists when you try to create your type. + Also, various old client software may assume that names beginning with + underscores always represent arrays. </para> <para> diff --git a/doc/src/sgml/syntax.sgml b/doc/src/sgml/syntax.sgml index 7bb9c669820..f1b5fe9411e 100644 --- a/doc/src/sgml/syntax.sgml +++ b/doc/src/sgml/syntax.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.117 2007/02/20 14:04:50 momjian Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.118 2007/05/11 17:57:11 tgl Exp $ --> <chapter id="sql-syntax"> <title>SQL Syntax</title> @@ -131,10 +131,10 @@ INSERT INTO MY_TABLE VALUES (3, 'hi there'); <para> <indexterm><primary>identifier</primary><secondary>length</secondary></indexterm> The system uses no more than <symbol>NAMEDATALEN</symbol>-1 - characters of an identifier; longer names can be written in + bytes of an identifier; longer names can be written in commands, but they will be truncated. By default, <symbol>NAMEDATALEN</symbol> is 64 so the maximum identifier - length is 63. If this limit is problematic, it can be raised by + length is 63 bytes. If this limit is problematic, it can be raised by changing the <symbol>NAMEDATALEN</symbol> constant in <filename>src/include/pg_config_manual.h</filename>. </para> |