constraint to a table, noting
   that a table can only ever have one primary key:
<programlisting>
ALTER TABLE distributors ADD PRIMARY KEY (dist_id);
</programlisting>
  </para>

  <para>
   To move a table to a different tablespace:
<programlisting>
ALTER TABLE distributors SET TABLESPACE fasttablespace;
</programlisting>
  </para>

  <para>
   To move a table to a different schema:
<programlisting>
ALTER TABLE myschema.distributors SET SCHEMA yourschema;
</programlisting>
  </para>

  <para>
   To recreate a primary key constraint, without blocking updates while the
   index is rebuilt:
<programlisting>
CREATE UNIQUE INDEX CONCURRENTLY dist_id_temp_idx ON distributors (dist_id);
ALTER TABLE distributors DROP CONSTRAINT distributors_pkey,
    ADD CONSTRAINT distributors_pkey PRIMARY KEY USING INDEX dist_id_temp_idx;
</programlisting></para>

  <para>
   To attach a partition to a range-partitioned table:
<programlisting>
ALTER TABLE measurement
    ATTACH PARTITION measurement_y2016m07 FOR VALUES FROM ('2016-07-01') TO ('2016-08-01');
</programlisting></para>

  <para>
   To attach a partition to a list-partitioned table:
<programlisting>
ALTER TABLE cities
    ATTACH PARTITION cities_ab FOR VALUES IN ('a', 'b');
</programlisting></para>

  <para>
   To attach a partition to a hash-partitioned table:
<programlisting>
ALTER TABLE orders
    ATTACH PARTITION orders_p4 FOR VALUES WITH (MODULUS 4, REMAINDER 3);
</programlisting></para>

  <para>
   To attach a default partition to a partitioned table:
<programlisting>
ALTER TABLE cities
    ATTACH PARTITION cities_partdef DEFAULT;
</programlisting></para>

  <para>
   To detach a partition from a partitioned table:
<programlisting>
ALTER TABLE measurement
    DETACH PARTITION measurement_y2015m12;
</programlisting></para>

 </refsect1>

 <refsect1>
  <title>Compatibility</title>

  <para>
   The forms <literal>ADD [COLUMN]</literal>,
   <literal>DROP [COLUMN]</literal>, <literal>DROP IDENTITY</literal>, <literal>RESTART</literal>,
   <literal>SET DEFAULT</literal>, <literal>SET DATA TYPE</literal> (without <literal>USING</literal>),
   <literal>SET GENERATED</literal>, and <literal>SET <replaceable>sequence_option</replaceable></literal>
   conform with the SQL standard.
   The form <literal>ADD <replaceable>table_constraint</replaceable></literal>
   conforms with the SQL standard when the <literal>USING INDEX</literal> and
   <literal>NOT VALID</literal> clauses are omitted and the constraint type is
   one of <literal>CHECK</literal>, <literal>UNIQUE</literal>, <literal>PRIMARY KEY</literal>,
   or <literal>REFERENCES</literal>.
   The other forms are
   <productname>PostgreSQL</productname> extensions of the SQL standard.
   Also, the ability to specify more than one manipulation in a single
   <command>ALTER TABLE</command> command is an extension.
  </para>

  <para>
   <command>ALTER TABLE DROP COLUMN</command> can be used to drop the only
   column of a table, leaving a zero-column table.  This is an
   extension of SQL, which disallows zero-column tables.
  </para>
 </refsect1>

 <refsect1>
  <title>See Also</title>

  <simplelist type="inline">
   <member><xref linkend="sql-createtable"/></member>
  </simplelist>
 </refsect1>
</refentry>