diff options
Diffstat (limited to 'doc/src/sgml/ref/create_foreign_table.sgml')
| -rw-r--r-- | doc/src/sgml/ref/create_foreign_table.sgml | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/doc/src/sgml/ref/create_foreign_table.sgml b/doc/src/sgml/ref/create_foreign_table.sgml index 19eb5341e7..65ba3e3d37 100644 --- a/doc/src/sgml/ref/create_foreign_table.sgml +++ b/doc/src/sgml/ref/create_foreign_table.sgml @@ -42,7 +42,8 @@ CREATE FOREIGN TABLE [ IF NOT EXISTS ] <replaceable class="parameter">table_name { NOT NULL | NULL | CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] | - DEFAULT <replaceable>default_expr</replaceable> } + DEFAULT <replaceable>default_expr</replaceable> | + GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED } <phrase>and <replaceable class="parameter">table_constraint</replaceable> is:</phrase> @@ -259,6 +260,30 @@ CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO INHERIT ] </varlistentry> <varlistentry> + <term><literal>GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED</literal><indexterm><primary>generated column</primary></indexterm></term> + <listitem> + <para> + This clause creates the column as a <firstterm>generated + column</firstterm>. The column cannot be written to, and when read it + will be computed from the specified expression. + </para> + + <para> + The keyword <literal>STORED</literal> is required to signify that the + column will be computed on write. (The computed value will be presented + to the foreign-data wrapper for storage and must be returned on + reading.) + </para> + + <para> + The generation expression can refer to other columns in the table, but + not other generated columns. Any functions and operators used must be + immutable. References to other tables are not allowed. + </para> + </listitem> + </varlistentry> + + <varlistentry> <term><replaceable class="parameter">server_name</replaceable></term> <listitem> <para> |