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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>ALTER TYPE</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="sql-altertrigger.html" title="ALTER TRIGGER" /><link rel="next" href="sql-alteruser.html" title="ALTER USER" /></head><body><div xmlns="http://www.w3.org/TR/xhtml1/transitional" class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">ALTER TYPE</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="sql-altertrigger.html" title="ALTER TRIGGER">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="sql-commands.html" title="SQL Commands">Up</a></td><th width="60%" align="center">SQL Commands</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 11.5 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="sql-alteruser.html" title="ALTER USER">Next</a></td></tr></table><hr></hr></div><div class="refentry" id="SQL-ALTERTYPE"><div class="titlepage"></div><a id="id-1.9.3.42.1" class="indexterm"></a><div class="refnamediv"><h2><span class="refentrytitle">ALTER TYPE</span></h2><p>ALTER TYPE —
change the definition of a type
</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><pre class="synopsis">
ALTER TYPE <em class="replaceable"><code>name</code></em> <em class="replaceable"><code>action</code></em> [, ... ]
ALTER TYPE <em class="replaceable"><code>name</code></em> OWNER TO { <em class="replaceable"><code>new_owner</code></em> | CURRENT_USER | SESSION_USER }
ALTER TYPE <em class="replaceable"><code>name</code></em> RENAME ATTRIBUTE <em class="replaceable"><code>attribute_name</code></em> TO <em class="replaceable"><code>new_attribute_name</code></em> [ CASCADE | RESTRICT ]
ALTER TYPE <em class="replaceable"><code>name</code></em> RENAME TO <em class="replaceable"><code>new_name</code></em>
ALTER TYPE <em class="replaceable"><code>name</code></em> SET SCHEMA <em class="replaceable"><code>new_schema</code></em>
ALTER TYPE <em class="replaceable"><code>name</code></em> ADD VALUE [ IF NOT EXISTS ] <em class="replaceable"><code>new_enum_value</code></em> [ { BEFORE | AFTER } <em class="replaceable"><code>neighbor_enum_value</code></em> ]
ALTER TYPE <em class="replaceable"><code>name</code></em> RENAME VALUE <em class="replaceable"><code>existing_enum_value</code></em> TO <em class="replaceable"><code>new_enum_value</code></em>
<span class="phrase">where <em class="replaceable"><code>action</code></em> is one of:</span>
ADD ATTRIBUTE <em class="replaceable"><code>attribute_name</code></em> <em class="replaceable"><code>data_type</code></em> [ COLLATE <em class="replaceable"><code>collation</code></em> ] [ CASCADE | RESTRICT ]
DROP ATTRIBUTE [ IF EXISTS ] <em class="replaceable"><code>attribute_name</code></em> [ CASCADE | RESTRICT ]
ALTER ATTRIBUTE <em class="replaceable"><code>attribute_name</code></em> [ SET DATA ] TYPE <em class="replaceable"><code>data_type</code></em> [ COLLATE <em class="replaceable"><code>collation</code></em> ] [ CASCADE | RESTRICT ]
</pre></div><div class="refsect1" id="id-1.9.3.42.5"><h2>Description</h2><p>
<code class="command">ALTER TYPE</code> changes the definition of an existing type.
There are several subforms:
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><code class="literal">ADD ATTRIBUTE</code></span></dt><dd><p>
This form adds a new attribute to a composite type, using the same syntax as
<a class="xref" href="sql-createtype.html" title="CREATE TYPE"><span class="refentrytitle">CREATE TYPE</span></a>.
</p></dd><dt><span class="term"><code class="literal">DROP ATTRIBUTE [ IF EXISTS ]</code></span></dt><dd><p>
This form drops an attribute from a composite type.
If <code class="literal">IF EXISTS</code> is specified and the attribute
does not exist, no error is thrown. In this case a notice
is issued instead.
</p></dd><dt><span class="term"><code class="literal">SET DATA TYPE</code></span></dt><dd><p>
This form changes the type of an attribute of a composite type.
</p></dd><dt><span class="term"><code class="literal">OWNER</code></span></dt><dd><p>
This form changes the owner of the type.
</p></dd><dt><span class="term"><code class="literal">RENAME</code></span></dt><dd><p>
This form changes the name of the type or the name of an
individual attribute of a composite type.
</p></dd><dt><span class="term"><code class="literal">SET SCHEMA</code></span></dt><dd><p>
This form moves the type into another schema.
</p></dd><dt><span class="term"><code class="literal">ADD VALUE [ IF NOT EXISTS ] [ BEFORE | AFTER ]</code></span></dt><dd><p>
This form adds a new value to an enum type. The new value's place in
the enum's ordering can be specified as being <code class="literal">BEFORE</code>
or <code class="literal">AFTER</code> one of the existing values. Otherwise,
the new item is added at the end of the list of values.
</p><p>
If <code class="literal">IF NOT EXISTS</code> is specified, it is not an error if
the type already contains the new value: a notice is issued but no other
action is taken. Otherwise, an error will occur if the new value is
already present.
</p></dd><dt><span class="term"><code class="literal">RENAME VALUE</code></span></dt><dd><p>
This form renames a value of an enum type.
The value's place in the enum's ordering is not affected.
An error will occur if the specified value is not present or the new
name is already present.
</p></dd></dl></div><p>
</p><p>
The <code class="literal">ADD ATTRIBUTE</code>, <code class="literal">DROP
ATTRIBUTE</code>, and <code class="literal">ALTER ATTRIBUTE</code> 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.
</p><p>
You must own the type to use <code class="command">ALTER TYPE</code>.
To change the schema of a type, you must also have
<code class="literal">CREATE</code> privilege on the new schema.
To alter the owner, you must also be a direct or indirect member of the new
owning role, and that role must have <code class="literal">CREATE</code> privilege on
the type's schema. (These restrictions enforce that altering the owner
doesn't do anything you couldn't do by dropping and recreating the type.
However, a superuser can alter ownership of any type anyway.)
To add an attribute or alter an attribute type, you must also
have <code class="literal">USAGE</code> privilege on the data type.
</p></div><div class="refsect1" id="id-1.9.3.42.6"><h2>Parameters</h2><p>
</p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><em class="replaceable"><code>name</code></em></span></dt><dd><p>
The name (possibly schema-qualified) of an existing type to
alter.
</p></dd><dt><span class="term"><em class="replaceable"><code>new_name</code></em></span></dt><dd><p>
The new name for the type.
</p></dd><dt><span class="term"><em class="replaceable"><code>new_owner</code></em></span></dt><dd><p>
The user name of the new owner of the type.
</p></dd><dt><span class="term"><em class="replaceable"><code>new_schema</code></em></span></dt><dd><p>
The new schema for the type.
</p></dd><dt><span class="term"><em class="replaceable"><code>attribute_name</code></em></span></dt><dd><p>
The name of the attribute to add, alter, or drop.
</p></dd><dt><span class="term"><em class="replaceable"><code>new_attribute_name</code></em></span></dt><dd><p>
The new name of the attribute to be renamed.
</p></dd><dt><span class="term"><em class="replaceable"><code>data_type</code></em></span></dt><dd><p>
The data type of the attribute to add, or the new type of the
attribute to alter.
</p></dd><dt><span class="term"><em class="replaceable"><code>new_enum_value</code></em></span></dt><dd><p>
The new value to be added to an enum type's list of values,
or the new name to be given to an existing value.
Like all enum literals, it needs to be quoted.
</p></dd><dt><span class="term"><em class="replaceable"><code>neighbor_enum_value</code></em></span></dt><dd><p>
The existing enum value that the new value should be added immediately
before or after in the enum type's sort ordering.
Like all enum literals, it needs to be quoted.
</p></dd><dt><span class="term"><em class="replaceable"><code>existing_enum_value</code></em></span></dt><dd><p>
The existing enum value that should be renamed.
Like all enum literals, it needs to be quoted.
</p></dd><dt><span class="term"><code class="literal">CASCADE</code></span></dt><dd><p>
Automatically propagate the operation to typed tables of the
type being altered, and their descendants.
</p></dd><dt><span class="term"><code class="literal">RESTRICT</code></span></dt><dd><p>
Refuse the operation if the type being altered is the type of a
typed table. This is the default.
</p></dd></dl></div><p>
</p></div><div class="refsect1" id="id-1.9.3.42.7"><h2>Notes</h2><p>
<code class="command">ALTER TYPE ... ADD VALUE</code> (the form that adds a new value to an
enum type) cannot be executed inside a transaction block.
</p><p>
Comparisons involving an added enum value will sometimes be slower than
comparisons involving only original members of the enum type. This will
usually only occur if <code class="literal">BEFORE</code> or <code class="literal">AFTER</code>
is used to set the new value's sort position somewhere other than at the
end of the list. However, sometimes it will happen even though the new
value is added at the end (this occurs if the OID counter <span class="quote">“<span class="quote">wrapped
around</span>”</span> since the original creation of the enum type). The slowdown is
usually insignificant; but if it matters, optimal performance can be
regained by dropping and recreating the enum type, or by dumping and
reloading the database.
</p></div><div class="refsect1" id="id-1.9.3.42.8"><h2>Examples</h2><p>
To rename a data type:
</p><pre class="programlisting">
ALTER TYPE electronic_mail RENAME TO email;
</pre><p>
</p><p>
To change the owner of the type <code class="literal">email</code>
to <code class="literal">joe</code>:
</p><pre class="programlisting">
ALTER TYPE email OWNER TO joe;
</pre><p>
</p><p>
To change the schema of the type <code class="literal">email</code>
to <code class="literal">customers</code>:
</p><pre class="programlisting">
ALTER TYPE email SET SCHEMA customers;
</pre><p>
</p><p>
To add a new attribute to a type:
</p><pre class="programlisting">
ALTER TYPE compfoo ADD ATTRIBUTE f3 int;
</pre><p>
</p><p>
To add a new value to an enum type in a particular sort position:
</p><pre class="programlisting">
ALTER TYPE colors ADD VALUE 'orange' AFTER 'red';
</pre><p>
</p><p>
To rename an enum value:
</p><pre class="programlisting">
ALTER TYPE colors RENAME VALUE 'purple' TO 'mauve';
</pre></div><div class="refsect1" id="id-1.9.3.42.9"><h2>Compatibility</h2><p>
The variants to add and drop attributes are part of the SQL
standard; the other variants are PostgreSQL extensions.
</p></div><div class="refsect1" id="SQL-ALTERTYPE-SEE-ALSO"><h2>See Also</h2><span class="simplelist"><a class="xref" href="sql-createtype.html" title="CREATE TYPE"><span class="refentrytitle">CREATE TYPE</span></a>, <a class="xref" href="sql-droptype.html" title="DROP TYPE"><span class="refentrytitle">DROP TYPE</span></a></span></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="sql-altertrigger.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="sql-commands.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="sql-alteruser.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">ALTER TRIGGER </td><td width="20%" align="center"><a accesskey="h" href="index.html">Home</a></td><td width="40%" align="right" valign="top"> ALTER USER</td></tr></table></div></body></html>
