Add ALTER TYPE ... ADD/DROP/ALTER/RENAME ATTRIBUTE

Like with tables, this also requires allowing the existence of
composite types with zero attributes.

reviewed by KaiGai Kohei

3 files changed, 143 insertions, 13 deletions

diff --git a/doc/src/sgml/ref/alter_type.sgml b/doc/src/sgml/ref/alter_type.sgml
index d76feb48c30..315922ea836 100644
--- a/doc/src/sgml/ref/alter_type.sgml
+++ b/doc/src/sgml/ref/alter_type.sgml
@@ -23,9 +23,17 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-ALTER TYPE <replaceable class="PARAMETER">name</replaceable> RENAME TO <replaceable class="PARAMETER">new_name</replaceable>
+ALTER TYPE <replaceable class="PARAMETER">name</replaceable> <replaceable class="PARAMETER">action</replaceable> [, ... ]
 ALTER TYPE <replaceable class="PARAMETER">name</replaceable> OWNER TO <replaceable class="PARAMETER">new_owner</replaceable> 
+ALTER TYPE <replaceable class="PARAMETER">name</replaceable> RENAME ATTRIBUTE <replaceable class="PARAMETER">attribute_name</replaceable> TO <replaceable class="PARAMETER">new_attribute_name</replaceable>
+ALTER TYPE <replaceable class="PARAMETER">name</replaceable> RENAME TO <replaceable class="PARAMETER">new_name</replaceable>
 ALTER TYPE <replaceable class="PARAMETER">name</replaceable> SET SCHEMA <replaceable class="PARAMETER">new_schema</replaceable>
+
+<phrase>where <replaceable class="PARAMETER">action</replaceable> is one of:</phrase>
+
+    ADD ATTRIBUTE <replaceable class="PARAMETER">attribute_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable>
+    DROP ATTRIBUTE [ IF EXISTS ] <replaceable class="PARAMETER">attribute_name</replaceable>
+    ALTER ATTRIBUTE <replaceable class="PARAMETER">attribute_name</replaceable> [ SET DATA ] TYPE <replaceable class="PARAMETER">data_type</replaceable>
 </synopsis>
  </refsynopsisdiv>
 
@@ -34,6 +42,76 @@ ALTER TYPE <replaceable class="PARAMETER">name</replaceable> SET SCHEMA <replace
 
   <para>
    <command>ALTER TYPE</command> changes the definition of an existing type.
+   There are several subforms:
+
+  <variablelist>
+   <varlistentry>
+    <term><literal>ADD ATTRIBUTE</literal></term>
+    <listitem>
+     <para>
+      This form adds a new attribute to a composite type, using the same syntax as
+      <xref linkend="SQL-CREATETYPE">.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>DROP ATTRIBUTE [ IF EXISTS ]</literal></term>
+    <listitem>
+     <para>
+      This form drops an attribute from a composite type.
+      If <literal>IF EXISTS</literal> is specified and the attribute
+      does not exist, no error is thrown. In this case a notice
+      is issued instead.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>SET DATA TYPE</literal></term>
+    <listitem>
+     <para>
+      This form changes the type of an attribute of a composite type.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>OWNER</literal></term>
+    <listitem>
+     <para>
+      This form changes the owner of the type.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>RENAME</literal></term>
+    <listitem>
+     <para>
+      This form changes the name of the type or the name of an
+      individual attribute of a composite type.
+     </para>
+    </listitem>
+   </varlistentry>
+
+   <varlistentry>
+    <term><literal>SET SCHEMA</literal></term>
+    <listitem>
+     <para>
+      This form moves the type into another schema.
+     </para>
+    </listitem>
+   </varlistentry>
+  </variablelist>
+  </para>
+
+  <para>
+   The <literal>ADD ATTRIBUTE</literal>, <literal>DROP
+   ATTRIBUTE</literal>, and <literal>ALTER ATTRIBUTE</literal> actions
+   can be combined into a list of multiple alterations to apply in
+   parallel.  For example, it is possible to add several attributes
+   and/or alter the type of several attributes in a single command.
   </para>
 
   <para>
@@ -90,6 +168,34 @@ ALTER TYPE <replaceable class="PARAMETER">name</replaceable> SET SCHEMA <replace
       </listitem>
      </varlistentry>
 
+     <varlistentry>
+      <term><replaceable class="PARAMETER">attribute_name</replaceable></term>
+      <listitem>
+       <para>
+        The name of the attribute to add, alter, or drop.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><replaceable class="PARAMETER">new_attribute_name</replaceable></term>
+      <listitem>
+       <para>
+        The new name of the attribute begin renamed.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
+      <term><replaceable class="PARAMETER">data_type</replaceable></term>
+      <listitem>
+       <para>
+        The data type of the attribute to add, or the new type of the
+        attribute to alter.
+       </para>
+      </listitem>
+     </varlistentry>
+
     </variablelist>
    </para>
   </refsect1>
@@ -119,14 +225,30 @@ ALTER TYPE email OWNER TO joe;
 ALTER TYPE email SET SCHEMA customers;
 </programlisting>
   </para>
+
+  <para>
+   To add a new attribute to a type:
+<programlisting>
+ALTER TYPE compfoo ADD ATTRIBUTE f3 int;
+</programlisting>
+  </para>
  </refsect1>
 
  <refsect1>
   <title>Compatibility</title>
-    
+
   <para>
-   There is no <command>ALTER TYPE</command> statement in the SQL
-   standard.
+   The variants to add and drop attributes are part of the SQL
+   standard; the other variants are PostgreSQL extensions.
   </para>
  </refsect1>
+
+ <refsect1 id="SQL-ALTERTYPE-see-also">
+  <title>See Also</title>
+
+  <simplelist type="inline">
+   <member><xref linkend="sql-createtype"></member>
+   <member><xref linkend="sql-droptype"></member>
+  </simplelist>
+ </refsect1>
 </refentry>
diff --git a/doc/src/sgml/ref/create_type.sgml b/doc/src/sgml/ref/create_type.sgml
index ca521b387b3..a3c75b51d0f 100644
--- a/doc/src/sgml/ref/create_type.sgml
+++ b/doc/src/sgml/ref/create_type.sgml
@@ -22,7 +22,7 @@ PostgreSQL documentation
  <refsynopsisdiv>
 <synopsis>
 CREATE TYPE <replaceable class="parameter">name</replaceable> AS
-    ( <replaceable class="PARAMETER">attribute_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [, ... ] )
+    ( [ <replaceable class="PARAMETER">attribute_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [, ... ] ] )
 
 CREATE TYPE <replaceable class="parameter">name</replaceable> AS ENUM
     ( [ '<replaceable class="parameter">label</replaceable>' [, ... ] ] )
@@ -768,10 +768,18 @@ CREATE TABLE big_objs (
   <title>Compatibility</title>
 
   <para>
-   This <command>CREATE TYPE</command> command is a
-   <productname>PostgreSQL</productname> extension.  There is a
-   <command>CREATE TYPE</command> statement in the <acronym>SQL</> standard
-   that is rather different in detail.
+   The first form of the <command>CREATE TYPE</command> command, which
+   creates a composite type, conforms to the <acronym>SQL</> standard.
+   The other forms are <productname>PostgreSQL</productname>
+   extensions.  The <command>CREATE TYPE</command> statement in
+   the <acronym>SQL</> standard also defines other forms that are not
+   implemented in <productname>PostgreSQL</>.
+  </para>
+
+  <para>
+   The ability to create a composite type with zero attributes is
+   a <productname>PostgreSQL</productname>-specific deviation from the
+   standard (analogous to <command>CREATE TABLE</command>).
   </para>
  </refsect1>
 
@@ -779,10 +787,10 @@ CREATE TABLE big_objs (
   <title>See Also</title>
 
   <simplelist type="inline">
-   <member><xref linkend="sql-createfunction"></member>
-   <member><xref linkend="sql-droptype"></member>
    <member><xref linkend="sql-altertype"></member>
    <member><xref linkend="sql-createdomain"></member>
+   <member><xref linkend="sql-createfunction"></member>
+   <member><xref linkend="sql-droptype"></member>
   </simplelist>
  </refsect1>
 
diff --git a/doc/src/sgml/ref/drop_type.sgml b/doc/src/sgml/ref/drop_type.sgml
index 10e3e143bc2..76e31517a1a 100644
--- a/doc/src/sgml/ref/drop_type.sgml
+++ b/doc/src/sgml/ref/drop_type.sgml
@@ -97,7 +97,7 @@ DROP TYPE box;
    This command is similar to the corresponding command in the SQL
    standard, apart from the <literal>IF EXISTS</>
    option, which is a <productname>PostgreSQL</> extension.
-   But note that the <command>CREATE TYPE</command> command
+   But note that much of the <command>CREATE TYPE</command> command
    and the data type extension mechanisms in
    <productname>PostgreSQL</productname> differ from the SQL standard.
   </para>
@@ -107,8 +107,8 @@ DROP TYPE box;
   <title>See Also</title>
 
   <simplelist type="inline">
-   <member><xref linkend="sql-createtype"></member>
    <member><xref linkend="sql-altertype"></member>
+   <member><xref linkend="sql-createtype"></member>
   </simplelist>
  </refsect1>