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Reclassify DEFAULT as a column_constraint item in the CREATE TABLE syntax.

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This is how it was documented originally, but several years ago somebody
decided that DEFAULT isn't a type of constraint.  Well, the grammar thinks
it is.  The documentation was wrong in two ways: it alleged that DEFAULT
had to appear before any other kind of constraint, and it alleged that you
can't prefix a DEFAULT clause with a "CONSTRAINT name" clause, when in fact
you can.  (The latter behavior probably isn't SQL-standard, but our grammar
has always allowed it.)

This patch responds to Fujii Masao's observation that the ALTER TABLE
documentation mistakenly implied that you couldn't include DEFAULT in
ALTER TABLE ADD COLUMN; though this isn't the way he proposed fixing it.
This commit is contained in:
Tom Lane 2010-12-28 21:38:05 -05:00
parent a5f96409fd
commit 31d2efaef5
2 changed files with 25 additions and 24 deletions
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2
doc/src/sgml/ref/alter_table.sgml
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@ -32,7 +32,7 @@ ALTER TABLE <replaceable class="PARAMETER">name</replaceable>
<phrase>where <replaceable class="PARAMETER">action</replaceable> is one of:</phrase>
ADD [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> <replaceable class="PARAMETER">type</replaceable> [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
ADD [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
DROP [ COLUMN ] [ IF EXISTS ] <replaceable class="PARAMETER">column</replaceable> [ RESTRICT | CASCADE ]
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> [ SET DATA ] TYPE <replaceable class="PARAMETER">type</replaceable> [ USING <replaceable class="PARAMETER">expression</replaceable> ]
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> SET DEFAULT <replaceable class="PARAMETER">expression</replaceable>

47
doc/src/sgml/ref/create_table.sgml
View File

@ -22,7 +22,7 @@ PostgreSQL documentation
<refsynopsisdiv>
<synopsis>
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name</replaceable> ( [
{ <replaceable class="PARAMETER">column_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ DEFAULT <replaceable>default_expr</replaceable> ] [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
{ <replaceable class="PARAMETER">column_name</replaceable> <replaceable class="PARAMETER">data_type</replaceable> [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
| <replaceable>table_constraint</replaceable>
| LIKE <replaceable>parent_table</replaceable> [ <replaceable>like_option</replaceable> ... ] }
[, ... ]
@ -34,7 +34,7 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE [ IF NOT EXISTS ] <repl
CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE [ IF NOT EXISTS ] <replaceable class="PARAMETER">table_name</replaceable>
OF <replaceable class="PARAMETER">type_name</replaceable> [ (
{ <replaceable class="PARAMETER">column_name</replaceable> WITH OPTIONS [ DEFAULT <replaceable>default_expr</replaceable> ] [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
{ <replaceable class="PARAMETER">column_name</replaceable> WITH OPTIONS [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
| <replaceable>table_constraint</replaceable> }
[, ... ]
) ]
@ -48,6 +48,7 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE [ IF NOT EXISTS ] <repl
{ NOT NULL |
NULL |
CHECK ( <replaceable class="PARAMETER">expression</replaceable> ) |
DEFAULT <replaceable>default_expr</replaceable> |
UNIQUE <replaceable class="PARAMETER">index_parameters</replaceable> |
PRIMARY KEY <replaceable class="PARAMETER">index_parameters</replaceable> |
REFERENCES <replaceable class="PARAMETER">reftable</replaceable> [ ( <replaceable class="PARAMETER">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
@ -226,27 +227,6 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE [ IF NOT EXISTS ] <repl
</listitem>
</varlistentry>
<varlistentry>
<term><literal>DEFAULT
<replaceable>default_expr</replaceable></literal></term>
<listitem>
<para>
The <literal>DEFAULT</> clause assigns a default data value for
the column whose column definition it appears within. The value
is any variable-free expression (subqueries and cross-references
to other columns in the current table are not allowed). The
data type of the default expression must match the data type of the
column.
</para>
<para>
The default expression will be used in any insert operation that
does not specify a value for the column. If there is no default
for a column, then the default is null.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>INHERITS ( <replaceable>parent_table</replaceable> [, ... ] )</literal></term>
<listitem>
@ -421,6 +401,27 @@ CREATE [ [ GLOBAL | LOCAL ] { TEMPORARY | TEMP } ] TABLE [ IF NOT EXISTS ] <repl
</listitem>
</varlistentry>
<varlistentry>
<term><literal>DEFAULT
<replaceable>default_expr</replaceable></literal></term>
<listitem>
<para>
The <literal>DEFAULT</> clause assigns a default data value for
the column whose column definition it appears within. The value
is any variable-free expression (subqueries and cross-references
to other columns in the current table are not allowed). The
data type of the default expression must match the data type of the
column.
</para>
<para>
The default expression will be used in any insert operation that
does not specify a value for the column. If there is no default
for a column, then the default is null.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>UNIQUE</> (column constraint)</term>
<term><literal>UNIQUE ( <replaceable class="PARAMETER">column_name</replaceable> [, ... ] )</> (table constraint)</term>