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| author | Peter Eisentraut <peter@eisentraut.org> | 2020-01-14 13:09:31 +0100 |
|---|---|---|
| committer | Peter Eisentraut <peter@eisentraut.org> | 2020-01-14 13:36:03 +0100 |
| commit | f595117e24a79db6072979ab5a757431fd17232f (patch) | |
| tree | 5fcc75646d3c32620d5525a2b4446fc22ad5b034 /doc/src | |
| parent | d751ba523546df2b2709c1ffd4d12d6a25e25bf6 (diff) | |
| download | postgresql-f595117e24a79db6072979ab5a757431fd17232f.tar.gz postgresql-f595117e24a79db6072979ab5a757431fd17232f.zip | |
ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION
Add an ALTER TABLE subcommand for dropping the generated property from
a column, per SQL standard.
Reviewed-by: Sergei Kornilov <sk@zsrv.org>
Discussion: https://www.postgresql.org/message-id/flat/2f7f1d9c-946e-0453-d841-4f38eb9d69b6%402ndquadrant.com
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/alter_table.sgml | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml index 8403c797e2e..4bf449587cc 100644 --- a/doc/src/sgml/ref/alter_table.sgml +++ b/doc/src/sgml/ref/alter_table.sgml @@ -46,6 +46,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable> ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET DEFAULT <replaceable class="parameter">expression</replaceable> ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> DROP DEFAULT ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> { SET | DROP } NOT NULL + ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> DROP EXPRESSION [ IF EXISTS ] ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> ADD GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> { SET GENERATED { ALWAYS | BY DEFAULT } | SET <replaceable>sequence_option</replaceable> | RESTART [ [ WITH ] <replaceable class="parameter">restart</replaceable> ] } [...] ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> DROP IDENTITY [ IF EXISTS ] @@ -242,6 +243,23 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM </varlistentry> <varlistentry> + <term><literal>DROP EXPRESSION [ IF EXISTS ]</literal></term> + <listitem> + <para> + This form turns a stored generated column into a normal base column. + Existing data in the columns is retained, but future changes will no + longer apply the generation expression. + </para> + + <para> + If <literal>DROP EXPRESSION IF EXISTS</literal> is specified and the + column is not a stored generated column, no error is thrown. In this + case a notice is issued instead. + </para> + </listitem> + </varlistentry> + + <varlistentry> <term><literal>ADD GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY</literal></term> <term><literal>SET GENERATED { ALWAYS | BY DEFAULT }</literal></term> <term><literal>DROP IDENTITY [ IF EXISTS ]</literal></term> |