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Add IF NOT EXISTS processing to ALTER TABLE ADD COLUMN

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Fabrízio de Royes Mello, reviewed by Payal Singh, Alvaro Herrera and
Michael Paquier.
This commit is contained in:
Andrew Dunstan
2015-07-29 21:30:00 -04:00
parent 632cd9f892
commit 2cd40adb85
5 changed files with 182 additions and 18 deletions
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8
doc/src/sgml/ref/alter_table.sgml
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@@ -36,7 +36,7 @@ ALTER TABLE ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable>
<phrase>where <replaceable class="PARAMETER">action</replaceable> is one of:</phrase>
ADD [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ COLLATE <replaceable class="PARAMETER">collation</replaceable> ] [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
ADD [ COLUMN ] [ IF NOT EXISTS ] <replaceable class="PARAMETER">column_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ COLLATE <replaceable class="PARAMETER">collation</replaceable> ] [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
DROP [ COLUMN ] [ IF EXISTS ] <replaceable class="PARAMETER">column_name</replaceable> [ RESTRICT | CASCADE ]
ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> [ SET DATA ] TYPE <replaceable class="PARAMETER">data_type</replaceable> [ COLLATE <replaceable class="PARAMETER">collation</replaceable> ] [ USING <replaceable class="PARAMETER">expression</replaceable> ]
ALTER [ COLUMN ] <replaceable class="PARAMETER">column_name</replaceable> SET DEFAULT <replaceable class="PARAMETER">expression</replaceable>
@@ -96,11 +96,13 @@ ALTER TABLE ALL IN TABLESPACE <replaceable class="PARAMETER">name</replaceable>
<variablelist>
<varlistentry>
<term><literal>ADD COLUMN</literal></term>
<term><literal>ADD COLUMN [ IF NOT EXISTS ]</literal></term>
<listitem>
<para>
This form adds a new column to the table, using the same syntax as
<xref linkend="SQL-CREATETABLE">.
<xref linkend="SQL-CREATETABLE">. If <literal>IF NOT EXISTS</literal>
is specified and a column already exists with this name,
no error is thrown.
</para>
</listitem>
</varlistentry>