functionality was added in 1995, its name was changed to Postgres95. The

name was changed at the end of 1996 to PostgreSQL.<P>

It is pronounced<I>Post-Gres-Q-L.</I>

<H4><ANAME="1.2">1.2</A>)What's the copyright on

PostgreSQL?</H4><P>

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class="PARAMETER">newcolumn</replaceable>

ALTER TABLE <replaceable class="PARAMETER">table</replaceable>

RENAME TO <replaceable class="PARAMETER">newtable</replaceable>

ALTER TABLE <replaceable class="PARAMETER">table</replaceable>

ADD <replaceable class="PARAMETER">table constraint definition</replaceable>

</synopsis>

<refsect2 id="R2-SQL-ALTERTABLE-1">

</para>

</listitem>

</varlistentry>

<varlistentry>

<term><replaceable class="PARAMETER"> table constraint definition </replaceable></term>

<listitem>

<para>

New table constraint for the table

</para>

</listitem>

</varlistentry>

</variablelist>

</para>

</refsect2>

the affected table. Thus, the table or column will

remain of the same type and size after this command is

executed.

The ADD <replaceable class="PARAMETER">table constraint definition</replaceable> clause

adds a new constraint to the table using the same syntax as <xref

linkend="SQL-CREATETABLE" endterm="SQL-CREATETABLE-title">.

</para>

<para>

endterm="sql-update-title">.)

</para>

<para>

In the current implementation, only FOREIGN KEY constraints can

be added to a table. To create or remove a unique constraint, create

a unique index (see <xref linkend="SQL-CREATEINDEX"

endterm="SQL-CREATEINDEX-title">). To add check constraints

you need to recreate and reload the table, using other

parameters to the <xref linkend="SQL-CREATETABLE"

endterm="SQL-CREATETABLE-title"> command.

</para>

<para>

You must own the class in order to change its schema.

Renaming any part of the schema of a system

ALTER TABLE distributors RENAME TO suppliers;

</programlisting>

</para>

<para>

To add a foreign key constraint to a table:

<programlisting>

ALTER TABLE distributors ADD CONSTRAINT distfk FOREIGN KEY (address) REFERENCES addresses(address) MATCH FULL

</programlisting>

</para>

</refsect1>

<refsect1 id="R1-SQL-ALTERTABLE-3">

<varlistentry>

<term>

<synopsis>

ALTER TABLE <replaceable class="PARAMETER">table</replaceable> ADD <replaceable class="PARAMETER">table constraint definition</replaceable>

ALTER TABLE <replaceable class="PARAMETER">table</replaceable> DROP CONSTRAINT <replaceable class="PARAMETER">constraint</replaceable> { RESTRICT | CASCADE }

</synopsis>

</term>

<listitem>

<para>

Adds or removes a table constraint (such as a check constraint,

unique constraint, or foreign key constraint). To create

or remove a unique constraint, create or drop a unique index,

respectively (see <xref linkend="SQL-CREATEINDEX" endterm="SQL-CREATEINDEX-title">).

To change other kinds of constraints you need to recreate

Removes a table constraint (such as a check constraint,

unique constraint, or foreign key constraint). To

remove a unique constraint, drop a unique index,

To remove other kinds of constraints you need to recreate

and reload the table, using other parameters to the

<xref linkend="SQL-CREATETABLE" endterm="SQL-CREATETABLE-title">

command.