1999-07-22 17:09:15 +02:00
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$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.61 2003/09/09 18:28:52 tgl Exp $
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PostgreSQL documentation
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1999-07-22 17:09:15 +02:00
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-->
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1999-07-06 19:16:42 +02:00
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<refentry id="SQL-ALTERTABLE">
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<refmeta>
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2002-04-21 21:02:39 +02:00
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<refentrytitle id="sql-altertable-title">ALTER TABLE</refentrytitle>
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1999-07-06 19:16:42 +02:00
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<refmiscinfo>SQL - Language Statements</refmiscinfo>
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</refmeta>
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1999-07-06 19:16:42 +02:00
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<refnamediv>
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2003-04-15 15:25:08 +02:00
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<refname>ALTER TABLE</refname>
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<refpurpose>change the definition of a table</refpurpose>
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1999-07-06 19:16:42 +02:00
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</refnamediv>
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2003-08-31 19:32:24 +02:00
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<indexterm zone="sql-altertable">
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<primary>ALTER TABLE</primary>
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</indexterm>
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1999-07-06 19:16:42 +02:00
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<refsynopsisdiv>
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<synopsis>
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2001-01-05 07:34:23 +01:00
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ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
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2001-10-12 02:07:15 +02:00
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ADD [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> <replaceable class="PARAMETER">type</replaceable> [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
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2002-08-02 20:15:10 +02:00
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ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
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DROP [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> [ RESTRICT | CASCADE ]
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2001-01-05 07:34:23 +01:00
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ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
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2002-04-23 04:07:16 +02:00
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ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> { SET DEFAULT <replaceable class="PARAMETER">value</replaceable> | DROP DEFAULT }
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2002-04-01 06:35:40 +02:00
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ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
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ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> { SET | DROP } NOT NULL
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2001-05-07 02:43:27 +02:00
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ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
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ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> SET STATISTICS <replaceable class="PARAMETER">integer</replaceable>
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2002-03-05 06:33:31 +01:00
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ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
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ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
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2003-02-13 06:20:05 +01:00
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ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
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SET WITHOUT OIDS
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ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
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2000-01-29 17:58:54 +01:00
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RENAME [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> TO <replaceable
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class="PARAMETER">new_column</replaceable>
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ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
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2002-02-17 00:45:48 +01:00
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RENAME TO <replaceable class="PARAMETER">new_table</replaceable>
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2002-10-20 00:51:45 +02:00
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ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
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ADD <replaceable class="PARAMETER">table_constraint</replaceable>
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ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
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DROP CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable> [ RESTRICT | CASCADE ]
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ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
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OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
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ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
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CLUSTER ON <replaceable class="PARAMETER">index_name</replaceable>
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</synopsis>
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</refsynopsisdiv>
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2003-04-15 15:25:08 +02:00
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<refsect1>
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<title>Description</title>
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<para>
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<command>ALTER TABLE</command> changes the definition of an existing table.
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There are several subforms:
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<variablelist>
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<varlistentry>
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<term><literal>ADD COLUMN</literal></term>
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<listitem>
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<para>
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This form adds a new column to the table using the same syntax as
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<xref linkend="SQL-CREATETABLE" endterm="SQL-CREATETABLE-TITLE">.
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</para>
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</listitem>
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</varlistentry>
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2002-08-02 20:15:10 +02:00
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<varlistentry>
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<term><literal>DROP COLUMN</literal></term>
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<listitem>
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<para>
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This form drops a column from a table. Indexes and
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table constraints involving the column will be automatically
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dropped as well. You will need to say <literal>CASCADE</> if
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anything outside the table depends on the column, for example,
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foreign key references or views.
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2002-08-02 20:15:10 +02:00
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>SET</literal>/<literal>DROP DEFAULT</literal></term>
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<listitem>
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<para>
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These forms set or remove the default value for a column.
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The default values only apply to subsequent <command>INSERT</command>
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commands; they do not cause rows already in the table to change.
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Defaults may also be created for views, in which case they are
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inserted into <command>INSERT</> statements on the view before
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2003-04-15 15:25:08 +02:00
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the view's <literal>ON INSERT</literal> rule is applied.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>SET</literal>/<literal>DROP NOT NULL</literal></term>
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<listitem>
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<para>
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These forms change whether a column is marked to allow null
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values or to reject null values. You can only use <literal>SET
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NOT NULL</> when the column contains no null values.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>SET STATISTICS</literal></term>
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<listitem>
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<para>
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This form
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sets the per-column statistics-gathering target for subsequent
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<xref linkend="sql-analyze" endterm="sql-analyze-title"> operations.
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The target can be set in the range 0 to 1000; alternatively, set it
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to -1 to revert to using the system default statistics target.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>SET STORAGE</literal></term>
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<listitem>
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<para>
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This form sets the storage mode for a column. This controls whether this
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column is held inline or in a supplementary table, and whether the data
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should be compressed or not. <literal>PLAIN</literal> must be used
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for fixed-length values such as <type>integer</type> and is
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inline, uncompressed. <literal>MAIN</literal> is for inline,
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compressible data. <literal>EXTERNAL</literal> is for external,
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uncompressed data, and <literal>EXTENDED</literal> is for external,
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compressed data. <literal>EXTENDED</literal> is the default for all
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data types that support it. The use of <literal>EXTERNAL</literal> will, for example,
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make substring operations on a <type>text</type> column faster, at the penalty of
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2002-04-23 04:07:16 +02:00
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increased storage space.
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</para>
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</listitem>
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</varlistentry>
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2003-02-13 06:20:05 +01:00
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<varlistentry>
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2003-04-15 15:25:08 +02:00
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<term><literal>SET WITHOUT OIDS</literal></term>
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2003-02-13 06:20:05 +01:00
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<listitem>
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<para>
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This form removes the <literal>oid</literal> column from the
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table. Removing OIDs from a table does not occur immediately.
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The space that the OID uses will be reclaimed when the row is
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updated. Without updating the row, both the space and the value
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of the OID are kept indefinitely. This is semantically similar
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to the <literal>DROP COLUMN</literal> process.
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2003-02-13 06:20:05 +01:00
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</para>
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</listitem>
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</varlistentry>
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2002-04-23 04:07:16 +02:00
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<varlistentry>
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2003-04-15 15:25:08 +02:00
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<term><literal>RENAME</literal></term>
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<listitem>
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<para>
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The <literal>RENAME</literal> forms change the name of a table
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(or an index, sequence, or view) or the name of an individual column in
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a table. There is no effect on the stored data.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>ADD <replaceable class="PARAMETER">table_constraint</replaceable></literal></term>
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2002-04-23 04:07:16 +02:00
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<listitem>
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<para>
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This form adds a new constraint to a table using the same syntax as
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<xref linkend="SQL-CREATETABLE" endterm="SQL-CREATETABLE-TITLE">.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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2003-04-15 15:25:08 +02:00
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<term><literal>DROP CONSTRAINT</literal></term>
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<listitem>
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<para>
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2002-10-20 00:51:45 +02:00
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This form drops constraints on a table.
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Currently, constraints on tables are not required to have unique
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names, so there may be more than one constraint matching the specified
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name. All such constraints will be dropped.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><literal>OWNER</literal></term>
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<listitem>
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<para>
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This form changes the owner of the table, index, sequence, or view to the
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specified user.
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</para>
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</listitem>
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</varlistentry>
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2003-03-20 19:52:48 +01:00
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<varlistentry>
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2003-04-15 15:25:08 +02:00
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<term><literal>CLUSTER</literal></term>
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<listitem>
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<para>
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This form marks a table for future <xref linkend="SQL-CLUSTER" endterm="sql-cluster-title">
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operations.
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</para>
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</listitem>
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</varlistentry>
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2002-04-23 04:07:16 +02:00
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</variablelist>
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</para>
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1999-07-06 19:16:42 +02:00
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<para>
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2002-04-23 04:07:16 +02:00
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You must own the table to use <command>ALTER TABLE</>; except for
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<command>ALTER TABLE OWNER</>, which may only be executed by a superuser.
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</para>
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2003-04-15 15:25:08 +02:00
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</refsect1>
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<refsect1>
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<title>Parameters</title>
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<variablelist>
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<varlistentry>
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<term><replaceable class="PARAMETER">table</replaceable></term>
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<listitem>
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<para>
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The name (possibly schema-qualified) of an existing table to
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alter. If <literal>ONLY</> is specified, only that table is
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altered. If <literal>ONLY</> is not specified, the table and all
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its descendant tables (if any) are updated. <literal>*</> can be
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appended to the table name to indicate that descendant tables are
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to be altered, but in the current version, this is the default
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behavior. (In releases before 7.1, <literal>ONLY</> was the
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default behavior. The default can be altered by changing the
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configuration parameter <varname>sql_inheritance</varname>.)
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="PARAMETER">column</replaceable></term>
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<listitem>
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<para>
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Name of a new or existing column.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="PARAMETER">type</replaceable></term>
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<listitem>
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<para>
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Data type of the new column.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="PARAMETER">new_column</replaceable></term>
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<listitem>
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<para>
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New name for an existing column.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="PARAMETER">new_table</replaceable></term>
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<listitem>
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<para>
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New name for the table.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><replaceable class="PARAMETER">table_constraint</replaceable></term>
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<listitem>
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<para>
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New table constraint for the table.
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</para>
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</listitem>
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</varlistentry>
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|
|
|
|
|
<varlistentry>
|
|
|
|
<term><replaceable class="PARAMETER">constraint_name</replaceable></term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
Name of an existing constraint to drop.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term><replaceable class="PARAMETER">new_owner</replaceable></term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
The user name of the new owner of the table.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term><replaceable class="PARAMETER">index_name</replaceable></term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
The index name on which the table should be marked for clustering.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term><literal>CASCADE</literal></term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
Automatically drop objects that depend on the dropped column
|
|
|
|
or constraint (for example, views referencing the column).
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
<term><literal>RESTRICT</literal></term>
|
|
|
|
<listitem>
|
|
|
|
<para>
|
|
|
|
Refuse to drop the column or constraint if there are any dependent
|
|
|
|
objects. This is the default behavior.
|
|
|
|
</para>
|
|
|
|
</listitem>
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
</variablelist>
|
|
|
|
</refsect1>
|
|
|
|
|
|
|
|
<refsect1>
|
|
|
|
<title>Notes</title>
|
1999-07-06 19:16:42 +02:00
|
|
|
|
|
|
|
<para>
|
2003-04-15 15:25:08 +02:00
|
|
|
The key word <literal>COLUMN</literal> is noise and can be omitted.
|
1999-07-06 19:16:42 +02:00
|
|
|
</para>
|
1998-05-13 07:34:00 +02:00
|
|
|
|
1999-07-22 17:09:15 +02:00
|
|
|
<para>
|
2001-05-07 02:43:27 +02:00
|
|
|
In the current implementation of <literal>ADD COLUMN</literal>,
|
2003-04-15 15:25:08 +02:00
|
|
|
default and <literal>NOT NULL</> clauses for the new column are not supported.
|
|
|
|
The new column always comes into being with all values null.
|
2001-10-12 02:07:15 +02:00
|
|
|
You can use the <literal>SET DEFAULT</literal> form
|
2003-02-19 05:06:28 +01:00
|
|
|
of <command>ALTER TABLE</command> to set the default afterward.
|
2001-05-07 02:43:27 +02:00
|
|
|
(You may also want to update the already existing rows to the
|
2002-04-23 04:07:16 +02:00
|
|
|
new default value, using
|
|
|
|
<xref linkend="sql-update" endterm="sql-update-title">.)
|
|
|
|
If you want to mark the column non-null, use the <literal>SET NOT NULL</>
|
|
|
|
form after you've entered non-null values for the column in all rows.
|
1999-07-22 17:09:15 +02:00
|
|
|
</para>
|
|
|
|
|
2002-08-02 20:15:10 +02:00
|
|
|
<para>
|
2003-04-15 15:25:08 +02:00
|
|
|
The <literal>DROP COLUMN</literal> form does not physically remove
|
2002-08-02 20:15:10 +02:00
|
|
|
the column, but simply makes it invisible to SQL operations. Subsequent
|
2003-04-15 15:25:08 +02:00
|
|
|
insert and update operations in the table will store a null value for the column.
|
2002-08-02 20:15:10 +02:00
|
|
|
Thus, dropping a column is quick but it will not immediately reduce the
|
|
|
|
on-disk size of your table, as the space occupied
|
|
|
|
by the dropped column is not reclaimed. The space will be
|
|
|
|
reclaimed over time as existing rows are updated.
|
|
|
|
To reclaim the space at once, do a dummy <command>UPDATE</> of all rows
|
|
|
|
and then vacuum, as in:
|
2003-04-15 15:25:08 +02:00
|
|
|
<programlisting>
|
2002-08-02 20:15:10 +02:00
|
|
|
UPDATE table SET col = col;
|
|
|
|
VACUUM FULL table;
|
2003-04-15 15:25:08 +02:00
|
|
|
</programlisting>
|
2002-08-02 20:15:10 +02:00
|
|
|
</para>
|
|
|
|
|
2002-10-20 00:51:45 +02:00
|
|
|
<para>
|
2003-04-15 15:25:08 +02:00
|
|
|
If a table has any descendant tables, it is not permitted to add
|
|
|
|
or rename a column in the parent table without doing the same to
|
|
|
|
the descendants. That is, <command>ALTER TABLE ONLY</command>
|
2003-02-19 05:06:28 +01:00
|
|
|
will be rejected. This ensures that the descendants always have
|
|
|
|
columns matching the parent.
|
2002-10-20 00:51:45 +02:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
2003-02-19 05:06:28 +01:00
|
|
|
A recursive <literal>DROP COLUMN</literal> operation will remove a
|
|
|
|
descendant table's column only if the descendant does not inherit
|
|
|
|
that column from any other parents and never had an independent
|
|
|
|
definition of the column. A nonrecursive <literal>DROP
|
|
|
|
COLUMN</literal> (i.e., <command>ALTER TABLE ONLY ... DROP
|
|
|
|
COLUMN</command>) never removes any descendant columns, but
|
|
|
|
instead marks them as independently defined rather than inherited.
|
2002-10-20 00:51:45 +02:00
|
|
|
</para>
|
|
|
|
|
1999-07-22 17:09:15 +02:00
|
|
|
<para>
|
2003-04-15 15:25:08 +02:00
|
|
|
Changing any part of a system catalog table is not permitted.
|
1999-07-06 19:16:42 +02:00
|
|
|
</para>
|
1998-05-13 07:34:00 +02:00
|
|
|
|
1999-07-06 19:16:42 +02:00
|
|
|
<para>
|
|
|
|
Refer to <command>CREATE TABLE</command> for a further description
|
2003-04-15 15:25:08 +02:00
|
|
|
of valid parameters. <xref linkend="ddl"> has further information on
|
2003-01-19 01:13:31 +01:00
|
|
|
inheritance.
|
1999-07-06 19:16:42 +02:00
|
|
|
</para>
|
|
|
|
</refsect1>
|
1998-05-13 07:34:00 +02:00
|
|
|
|
2003-04-15 15:25:08 +02:00
|
|
|
<refsect1>
|
|
|
|
<title>Examples</title>
|
|
|
|
|
1999-07-06 19:16:42 +02:00
|
|
|
<para>
|
2002-01-20 23:19:57 +01:00
|
|
|
To add a column of type <type>varchar</type> to a table:
|
2003-04-15 15:25:08 +02:00
|
|
|
<programlisting>
|
|
|
|
ALTER TABLE distributors ADD COLUMN address varchar(30);
|
|
|
|
</programlisting>
|
1999-07-06 19:16:42 +02:00
|
|
|
</para>
|
1998-05-13 07:34:00 +02:00
|
|
|
|
2002-08-02 20:15:10 +02:00
|
|
|
<para>
|
|
|
|
To drop a column from a table:
|
2003-04-15 15:25:08 +02:00
|
|
|
<programlisting>
|
2002-08-02 20:15:10 +02:00
|
|
|
ALTER TABLE distributors DROP COLUMN address RESTRICT;
|
2003-04-15 15:25:08 +02:00
|
|
|
</programlisting>
|
2002-08-02 20:15:10 +02:00
|
|
|
</para>
|
|
|
|
|
1999-07-06 19:16:42 +02:00
|
|
|
<para>
|
1998-05-13 07:34:00 +02:00
|
|
|
To rename an existing column:
|
2003-04-15 15:25:08 +02:00
|
|
|
<programlisting>
|
1999-07-06 19:16:42 +02:00
|
|
|
ALTER TABLE distributors RENAME COLUMN address TO city;
|
2003-04-15 15:25:08 +02:00
|
|
|
</programlisting>
|
1999-07-06 19:16:42 +02:00
|
|
|
</para>
|
1998-05-13 07:34:00 +02:00
|
|
|
|
1999-07-06 19:16:42 +02:00
|
|
|
<para>
|
1998-05-13 07:34:00 +02:00
|
|
|
To rename an existing table:
|
2003-04-15 15:25:08 +02:00
|
|
|
<programlisting>
|
1999-07-06 19:16:42 +02:00
|
|
|
ALTER TABLE distributors RENAME TO suppliers;
|
2003-04-15 15:25:08 +02:00
|
|
|
</programlisting>
|
1999-07-06 19:16:42 +02:00
|
|
|
</para>
|
2002-04-01 06:35:40 +02:00
|
|
|
|
|
|
|
<para>
|
2003-04-15 15:25:08 +02:00
|
|
|
To add a not-null constraint to a column:
|
|
|
|
<programlisting>
|
2002-04-01 06:35:40 +02:00
|
|
|
ALTER TABLE distributors ALTER COLUMN street SET NOT NULL;
|
2003-04-15 15:25:08 +02:00
|
|
|
</programlisting>
|
|
|
|
To remove a not-null constraint from a column:
|
|
|
|
<programlisting>
|
2002-04-01 06:35:40 +02:00
|
|
|
ALTER TABLE distributors ALTER COLUMN street DROP NOT NULL;
|
2003-04-15 15:25:08 +02:00
|
|
|
</programlisting>
|
2002-04-01 06:35:40 +02:00
|
|
|
</para>
|
2000-04-11 16:43:54 +02:00
|
|
|
|
2001-05-09 15:27:15 +02:00
|
|
|
<para>
|
|
|
|
To add a check constraint to a table:
|
2003-04-15 15:25:08 +02:00
|
|
|
<programlisting>
|
2001-09-12 04:13:25 +02:00
|
|
|
ALTER TABLE distributors ADD CONSTRAINT zipchk CHECK (char_length(zipcode) = 5);
|
2003-04-15 15:25:08 +02:00
|
|
|
</programlisting>
|
2001-05-09 15:27:15 +02:00
|
|
|
</para>
|
|
|
|
|
2001-05-30 15:01:08 +02:00
|
|
|
<para>
|
|
|
|
To remove a check constraint from a table and all its children:
|
2003-04-15 15:25:08 +02:00
|
|
|
<programlisting>
|
2002-07-12 20:43:19 +02:00
|
|
|
ALTER TABLE distributors DROP CONSTRAINT zipchk;
|
2003-04-15 15:25:08 +02:00
|
|
|
</programlisting>
|
2001-05-30 15:01:08 +02:00
|
|
|
</para>
|
|
|
|
|
2000-04-11 16:43:54 +02:00
|
|
|
<para>
|
|
|
|
To add a foreign key constraint to a table:
|
2003-04-15 15:25:08 +02:00
|
|
|
<programlisting>
|
|
|
|
ALTER TABLE distributors ADD CONSTRAINT distfk FOREIGN KEY (address) REFERENCES addresses (address) MATCH FULL;
|
|
|
|
</programlisting>
|
2000-04-11 16:43:54 +02:00
|
|
|
</para>
|
2001-09-07 23:57:53 +02:00
|
|
|
|
|
|
|
<para>
|
2002-01-20 23:19:57 +01:00
|
|
|
To add a (multicolumn) unique constraint to a table:
|
2003-04-15 15:25:08 +02:00
|
|
|
<programlisting>
|
2001-09-12 04:13:25 +02:00
|
|
|
ALTER TABLE distributors ADD CONSTRAINT dist_id_zipcode_key UNIQUE (dist_id, zipcode);
|
2003-04-15 15:25:08 +02:00
|
|
|
</programlisting>
|
2002-02-17 12:50:09 +01:00
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
To add an automatically named primary key constraint to a table, noting
|
|
|
|
that a table can only ever have one primary key:
|
2003-04-15 15:25:08 +02:00
|
|
|
<programlisting>
|
2002-02-17 12:50:09 +01:00
|
|
|
ALTER TABLE distributors ADD PRIMARY KEY (dist_id);
|
2003-04-15 15:25:08 +02:00
|
|
|
</programlisting>
|
2001-09-07 23:57:53 +02:00
|
|
|
</para>
|
1999-07-06 19:16:42 +02:00
|
|
|
</refsect1>
|
1998-05-13 07:34:00 +02:00
|
|
|
|
2003-04-15 15:25:08 +02:00
|
|
|
<refsect1>
|
|
|
|
<title>Compatibility</title>
|
1998-09-16 16:43:12 +02:00
|
|
|
|
2003-04-15 15:25:08 +02:00
|
|
|
<para>
|
|
|
|
The <literal>ADD COLUMN</literal> form conforms with the SQL
|
|
|
|
standard, with the exception that it does not support defaults and
|
|
|
|
not-null constraints, as explained above. The <literal>ALTER
|
|
|
|
COLUMN</literal> form is in full conformance.
|
|
|
|
</para>
|
2002-12-16 20:08:25 +01:00
|
|
|
|
2003-04-15 15:25:08 +02:00
|
|
|
<para>
|
|
|
|
The clauses to rename tables, columns, indexes, views, and sequences are
|
|
|
|
<productname>PostgreSQL</productname> extensions of the SQL standard.
|
|
|
|
</para>
|
|
|
|
|
|
|
|
<para>
|
|
|
|
<command>ALTER TABLE DROP COLUMN</> 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>
|
1999-07-06 19:16:42 +02:00
|
|
|
</refsect1>
|
|
|
|
</refentry>
|
|
|
|
|
|
|
|
<!-- Keep this comment at the end of the file
|
|
|
|
Local variables:
|
|
|
|
mode: sgml
|
|
|
|
sgml-omittag:nil
|
|
|
|
sgml-shorttag:t
|
|
|
|
sgml-minimize-attributes:nil
|
|
|
|
sgml-always-quote-attributes:t
|
|
|
|
sgml-indent-step:1
|
|
|
|
sgml-indent-data:t
|
|
|
|
sgml-parent-document:nil
|
|
|
|
sgml-default-dtd-file:"../reference.ced"
|
|
|
|
sgml-exposed-tags:nil
|
|
|
|
sgml-local-catalogs:"/usr/lib/sgml/catalog"
|
|
|
|
sgml-local-ecat-files:nil
|
|
|
|
End:
|
|
|
|
-->
|