database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-12-15 02:22:24 +03:00
Code Activity

Update SQL-command reference pages for schema features.

Browse Source
This commit is contained in:
Tom Lane
2002-04-23 02:07:16 +00:00
parent 5dd1c713d0
commit 0c1fe3d2b9
38 changed files with 366 additions and 205 deletions
Download Patch File Download Diff File Expand all files Collapse all files

191
doc/src/sgml/ref/alter_table.sgml
View File

@@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.42 2002/04/21 19:02:39 thomas Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/alter_table.sgml,v 1.43 2002/04/23 02:07:15 tgl Exp $
PostgreSQL documentation
-->
@@ -24,23 +24,22 @@ PostgreSQL documentation
ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
ADD [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> <replaceable class="PARAMETER">type</replaceable> [ <replaceable class="PARAMETER">column_constraint</replaceable> [ ... ] ]
ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> { SET DEFAULT <replaceable
class="PARAMETER">value</replaceable> | DROP DEFAULT }
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> { SET DEFAULT <replaceable class="PARAMETER">value</replaceable> | DROP DEFAULT }
ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> { SET | DROP } NOT NULL
ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> SET STATISTICS <replaceable class="PARAMETER">integer</replaceable>
ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> SET STORAGE {PLAIN | EXTERNAL | EXTENDED | MAIN}
ALTER [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable> [ * ]
RENAME [ COLUMN ] <replaceable class="PARAMETER">column</replaceable> TO <replaceable
class="PARAMETER">newcolumn</replaceable>
class="PARAMETER">new_column</replaceable>
ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
RENAME TO <replaceable class="PARAMETER">new_table</replaceable>
ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
ADD <replaceable class="PARAMETER">table_constraint_definition</replaceable>
ALTER TABLE [ ONLY ] <replaceable class="PARAMETER">table</replaceable>
DROP CONSTRAINT <replaceable class="PARAMETER">constraint</replaceable> { RESTRICT | CASCADE }
DROP CONSTRAINT <replaceable class="PARAMETER">constraint_name</replaceable> { RESTRICT | CASCADE }
ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
OWNER TO <replaceable class="PARAMETER">new_owner</replaceable>
</synopsis>
@@ -58,7 +57,7 @@ ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
<term><replaceable class="PARAMETER"> table </replaceable></term>
<listitem>
<para>
The name of an existing table to alter.
The name (possibly schema-qualified) of an existing table to alter.
</para>
</listitem>
</varlistentry>
@@ -82,7 +81,7 @@ ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER"> newcolumn </replaceable></term>
<term><replaceable class="PARAMETER"> new_column </replaceable></term>
<listitem>
<para>
New name for an existing column.
@@ -103,7 +102,16 @@ ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
<term><replaceable class="PARAMETER"> table_constraint_definition </replaceable></term>
<listitem>
<para>
New table constraint for the table
New table constraint for the table.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER"> constraint_name </replaceable></term>
<listitem>
<para>
Name of an existing constraint to drop.
</para>
</listitem>
</varlistentry>
@@ -162,44 +170,124 @@ ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
</title>
<para>
<command>ALTER TABLE</command> changes the definition of an existing table.
The <literal>ADD COLUMN</literal> form adds a new column to the table
using the same syntax as <xref linkend="SQL-CREATETABLE" endterm="SQL-CREATETABLE-TITLE">.
The <literal>ALTER COLUMN SET/DROP DEFAULT</literal> forms
allow you to set or remove the default for the column. Note that defaults
only apply to subsequent <command>INSERT</command> commands; they do not
cause rows already in the table to change.
The <literal>ALTER COLUMN SET/DROP NOT NULL</literal> forms allow you to
change whether a column is marked to allow NULL values or to reject NULL
values.
The <literal>ALTER COLUMN SET STATISTICS</literal> form allows you to
set the statistics-gathering target for subsequent
<xref linkend="sql-analyze" endterm="sql-analyze-title"> operations.
The <literal>ALTER COLUMN SET STORAGE</literal> form allows the
column storage mode to be set. This controls whether this column is
held inline or in a supplementary table, and whether the data
should be compressed or not. <literal>PLAIN</literal> must be used
for fixed-length values such as <literal>INTEGER</literal> and is
inline, uncompressed. <literal>MAIN</literal> is for inline,
compressible data. <literal>EXTERNAL</literal> is for external,
uncompressed data and <literal>EXTENDED</literal> is for external,
compressed data. The use of <literal>EXTERNAL</literal> will make
substring operations on a column faster, at the penalty of
increased storage space.
The <literal>RENAME</literal> clause causes the name of a table,
column, index, sequence or view to change without changing any of the
data. The data will remain of the same type and size after the
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">.
The DROP CONSTRAINT <replaceable class="PARAMETER">constraint</replaceable> clause
drops all constraints on the table (and its children) that match <replaceable class="PARAMETER">constraint</replaceable>.
The OWNER clause changes the owner of the table, index, sequence or view to the
user <replaceable class="PARAMETER">new user</replaceable>.
There are several sub-forms:
</para>
<variablelist>
<varlistentry>
<term>ADD COLUMN</term>
<listitem>
<para>
This form adds a new column to the table using the same syntax as
<xref linkend="SQL-CREATETABLE" endterm="SQL-CREATETABLE-TITLE">.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET/DROP DEFAULT</term>
<listitem>
<para>
These forms set or remove the default value for a column. Note
that defaults only apply to subsequent <command>INSERT</command>
commands; they do not cause rows already in the table to change.
Defaults may also be created for views, in which case they are
inserted into <command>INSERT</> statements on the view before
the view's ON INSERT rule is applied.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET/DROP NOT NULL</term>
<listitem>
<para>
These forms change whether a column is marked to allow NULL
values or to reject NULL values. You may only <literal>SET NOT NULL</>
when the table contains no NULLs in the column.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET STATISTICS</term>
<listitem>
<para>
This form
sets the per-column statistics-gathering target for subsequent
<xref linkend="sql-analyze" endterm="sql-analyze-title"> operations.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>SET STORAGE</term>
<listitem>
<para>
This form sets the storage mode for a column. This controls whether this
column is held inline or in a supplementary table, and whether the data
should be compressed or not. <literal>PLAIN</literal> must be used
for fixed-length values such as <literal>INTEGER</literal> and is
inline, uncompressed. <literal>MAIN</literal> is for inline,
compressible data. <literal>EXTERNAL</literal> is for external,
uncompressed data and <literal>EXTENDED</literal> is for external,
compressed data. <literal>EXTENDED</literal> is the default for all
datatypes that support it. The use of <literal>EXTERNAL</literal> will
make substring operations on a TEXT column faster, at the penalty of
increased storage space.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>RENAME</term>
<listitem>
<para>
The <literal>RENAME</literal> forms change the name of a table
(or an index, sequence, or view) or the name of an individual column in
a table. There is no effect on the stored data.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>ADD <replaceable class="PARAMETER">table_constraint_definition</replaceable></term>
<listitem>
<para>
This form adds a new constraint to a table using the same syntax as
<xref linkend="SQL-CREATETABLE" endterm="SQL-CREATETABLE-TITLE">.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>DROP CONSTRAINT</term>
<listitem>
<para>
This form drops constraints on a table (and its children).
Currently, constraints on tables are not required to have unique
names, so there may be more than one constraint matching the specified
name. All such constraints will be dropped.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>OWNER</term>
<listitem>
<para>
This form changes the owner of the table, index, sequence or view to the
specified user.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
You must own the table in order to change its schema.
You must own the table to use <command>ALTER TABLE</>; except for
<command>ALTER TABLE OWNER</>, which may only be executed by a superuser.
</para>
<refsect2 id="R2-SQL-ALTERTABLE-3">
@@ -216,16 +304,20 @@ ALTER TABLE <replaceable class="PARAMETER">table</replaceable>
<para>
In the current implementation of <literal>ADD COLUMN</literal>,
default and NOT NULL clauses for the new column are not supported.
The new column always comes into being with all values NULL.
You can use the <literal>SET DEFAULT</literal> form
of <command>ALTER TABLE</command> to set the default later.
of <command>ALTER TABLE</command> to set the default afterwards.
(You may also want to update the already existing rows to the
new default value, using <xref linkend="sql-update" endterm="sql-update-title">.)
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.
</para>
<para>
In DROP CONSTRAINT, the RESTRICT keyword is required, although
dependencies are not yet checked. The CASCADE option is unsupported.
Currently DROP CONSTRAINT drops only CHECK constraints.
Currently DROP CONSTRAINT only handles CHECK constraints.
To remove a PRIMARY or UNIQUE constraint, drop the
relevant index using the <xref linkend="SQL-DROPINDEX" endterm="sql-dropindex-title"> command.
To remove FOREIGN KEY constraints you need to recreate
@@ -243,16 +335,15 @@ DROP TABLE temp;
</para>
<para>
You must own the table in order to change it.
Changing any part of the schema of a system
catalog is not permitted.
The <citetitle>PostgreSQL User's Guide</citetitle> has further
information on inheritance.
</para>
<para>
Refer to <command>CREATE TABLE</command> for a further description
of valid arguments.
The <citetitle>PostgreSQL User's Guide</citetitle> has further
information on inheritance.
</para>
</refsect2>
</refsect1>