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Support arrays of composite types, including the rowtypes of regular tables
and views (but not system catalogs, nor sequences or toast tables). Get rid of the hardwired convention that a type's array type is named exactly "_type", instead using a new column pg_type.typarray to provide the linkage. (It still will be named "_type", though, except in odd corner cases such as maximum-length type names.) Along the way, make tracking of owner and schema dependencies for types more uniform: a type directly created by the user has these dependencies, while a table rowtype or auto-generated array type does not have them, but depends on its parent object instead. David Fetter, Andrew Dunstan, Tom Lane
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‎doc/src/sgml/array.sgml

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@@ -1,4 +1,4 @@
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<!-- $PostgreSQL: pgsql/doc/src/sgml/array.sgml,v 1.60 2007/04/06 19:22:38 tgl Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/array.sgml,v 1.61 2007/05/11 17:57:11 tgl Exp $ -->
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<sect1 id="arrays">
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<title>Arrays</title>
@@ -10,8 +10,9 @@
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<para>
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<productname>PostgreSQL</productname> allows columns of a table to be
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defined as variable-length multidimensional arrays. Arrays of any
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built-in or user-defined base type or enum type can be created.
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(Arrays of composite types or domains are not yet supported, however.)
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built-in or user-defined base type, enum type, or composite type
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can be created.
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Arrays of domains are not yet supported.
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</para>
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<sect2>

‎doc/src/sgml/catalogs.sgml

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<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.150 2007/04/06 22:33:41 tgl Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.151 2007/05/11 17:57:11 tgl Exp $ -->
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<!--
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Documentation of the system catalogs, directed toward PostgreSQL developers
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-->
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</entry>
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</row>
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<row>
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<entry><structfield>typarray</structfield></entry>
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<entry><type>oid</type></entry>
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<entry><literal><link linkend="catalog-pg-type"><structname>pg_type</structname></link>.oid</literal></entry>
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<entry>
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If <structfield>typarray</structfield> is not 0 then it
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identifies another row in <structname>pg_type</structname>, which
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is the <quote>true</quote> array type having this type as element
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</entry>
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</row>
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<row>
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<entry><structfield>typinput</structfield></entry>
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<entry><type>regproc</type></entry>
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<entry></entry>
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<entry><para>
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<structfield>typndims</structfield> is the number of array dimensions
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for a domain that is an array (that is, <structfield>typbasetype</> is an array type;
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the domain's <structfield>typelem</> will match the base type's <structfield>typelem</structfield>).
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Zero for types other than array domains
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for a domain that is an array (that is, <structfield>typbasetype</> is
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an array type; the domain's <structfield>typelem</> will match the base
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type's <structfield>typelem</structfield>).
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Zero for types other than domains over array types
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</para></entry>
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</row>
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‎doc/src/sgml/ref/create_type.sgml

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<!--
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$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.69 2007/04/02 03:49:37 tgl Exp $
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$PostgreSQL: pgsql/doc/src/sgml/ref/create_type.sgml,v 1.70 2007/05/11 17:57:11 tgl Exp $
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PostgreSQL documentation
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-->
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@@ -312,15 +312,17 @@ CREATE TYPE <replaceable class="parameter">name</replaceable>
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<title>Array Types</title>
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<para>
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Whenever a user-defined base or enum data type is created,
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Whenever a user-defined type is created,
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<productname>PostgreSQL</productname> automatically creates an
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associated array type, whose name consists of the base type's
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name prepended with an underscore. The parser understands this
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naming convention, and translates requests for columns of type
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<literal>foo[]</> into requests for type <literal>_foo</>.
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The implicitly-created array type is variable length and uses the
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name prepended with an underscore, and truncated if necessary to keep
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it less than <symbol>NAMEDATALEN</symbol> bytes long. (If the name
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so generated collides with an existing type name, the process is
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repeated until a non-colliding name is found.)
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This implicitly-created array type is variable length and uses the
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built-in input and output functions <literal>array_in</> and
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<literal>array_out</>.
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<literal>array_out</>. The array type tracks any changes in its
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element type's owner or schema, and is dropped if the element type is.
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</para>
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<para>
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making a fixed-length type that happens to be internally an array of a number of
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identical things, and you want to allow these things to be accessed
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directly by subscripting, in addition to whatever operations you plan
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to provide for the type as a whole. For example, type <type>name</>
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allows its constituent <type>char</> elements to be accessed this way.
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A 2-D <type>point</> type could allow its two component numbers to be
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accessed like <literal>point[0]</> and <literal>point[1]</>.
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to provide for the type as a whole. For example, type <type>point</>
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is represented as just two floating-point numbers, which it allows to be
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accessed as <literal>point[0]</> and <literal>point[1]</>.
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Note that
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this facility only works for fixed-length types whose internal form
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is exactly a sequence of identical fixed-length fields. A subscriptable
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<title>Notes</title>
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<para>
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User-defined type names should not begin with the underscore character
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(<literal>_</literal>) and should only be 62 characters
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long (or in general <symbol>NAMEDATALEN</symbol> - 2, rather than
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the <symbol>NAMEDATALEN</symbol> - 1 characters allowed for other
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names). Type names beginning with underscore are reserved for
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internally-created array type names.
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It is best to avoid using type names that begin with the underscore
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character (<literal>_</literal>). <productname>PostgreSQL</productname>
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forms the name of an array type by prepending one or more underscores
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to the element type's name, and these names may collide with user-defined
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type names that begin with underscore. While the system will modify
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generated array type names to avoid collisions, this does not help if the
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conflicting array type already exists when you try to create your type.
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Also, various old client software may assume that names beginning with
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underscores always represent arrays.
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</para>
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<para>

‎doc/src/sgml/syntax.sgml

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<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.117 2007/02/20 14:04:50 momjian Exp $ -->
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<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.118 2007/05/11 17:57:11 tgl Exp $ -->
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<chapter id="sql-syntax">
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<title>SQL Syntax</title>
@@ -131,10 +131,10 @@ INSERT INTO MY_TABLE VALUES (3, 'hi there');
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<para>
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<indexterm><primary>identifier</primary><secondary>length</secondary></indexterm>
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The system uses no more than <symbol>NAMEDATALEN</symbol>-1
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characters of an identifier; longer names can be written in
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bytes of an identifier; longer names can be written in
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commands, but they will be truncated. By default,
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<symbol>NAMEDATALEN</symbol> is 64 so the maximum identifier
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length is 63. If this limit is problematic, it can be raised by
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length is 63 bytes. If this limit is problematic, it can be raised by
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changing the <symbol>NAMEDATALEN</symbol> constant in
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<filename>src/include/pg_config_manual.h</filename>.
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</para>

‎src/backend/catalog/README

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$PostgreSQL: pgsql/src/backend/catalog/README,v 1.10 2006/07/31 01:16:36 tgl Exp $
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$PostgreSQL: pgsql/src/backend/catalog/README,v 1.11 2007/05/11 17:57:11 tgl Exp $
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This directory contains .c files that manipulate the system catalogs;
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src/include/catalog contains the .h files that define the structure
@@ -86,9 +86,9 @@ general) assumes that the fixed-length portions of all system catalog
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tuples are in fact present, because it maps C struct declarations onto
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them. Thus, the variable-length fields must all be at the end, and
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only the variable-length fields of a catalog tuple are permitted to be
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NULL. For example, if you set pg_type.typdelim to be NULL, a
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piece of code will likely perform "typetup->typdelim" (or, worse,
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"typetyp->typelem", which follows typdelim). This will result in
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NULL. For example, if you set pg_type.typrelid to be NULL, a
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piece of code will likely perform "typetup->typrelid" (or, worse,
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"typetyp->typelem", which follows typrelid). This will result in
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random errors or even segmentation violations. Hence, do NOT insert
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catalog tuples that contain NULL attributes except in their
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variable-length portions! (The bootstrapping code is fairly good about

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