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Don't use SGML empty tags

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For DocBook XML compatibility, don't use SGML empty tags (</>) anymore,
replace by the full tag name.  Add a warning option to catch future
occurrences.

Alexander Lakhin, Jürgen Purtz
This commit is contained in:
Peter Eisentraut
2017-10-08 21:44:17 -04:00
parent 6ecabead4b
commit c29c578908
337 changed files with 31636 additions and 31635 deletions
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172
doc/src/sgml/ref/create_trigger.sgml
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@@ -86,10 +86,10 @@ CREATE [ CONSTRAINT ] TRIGGER <replaceable class="parameter">name</replaceable>
</para>
<para>
Triggers that are specified to fire <literal>INSTEAD OF</> the trigger
event must be marked <literal>FOR EACH ROW</>, and can only be defined
on views. <literal>BEFORE</> and <literal>AFTER</> triggers on a view
must be marked as <literal>FOR EACH STATEMENT</>.
Triggers that are specified to fire <literal>INSTEAD OF</literal> the trigger
event must be marked <literal>FOR EACH ROW</literal>, and can only be defined
on views. <literal>BEFORE</literal> and <literal>AFTER</literal> triggers on a view
must be marked as <literal>FOR EACH STATEMENT</literal>.
</para>
<para>
@@ -115,35 +115,35 @@ CREATE [ CONSTRAINT ] TRIGGER <replaceable class="parameter">name</replaceable>
</thead>
<tbody>
<row>
<entry align="center" morerows="1"><literal>BEFORE</></entry>
<entry align="center"><command>INSERT</>/<command>UPDATE</>/<command>DELETE</></entry>
<entry align="center" morerows="1"><literal>BEFORE</literal></entry>
<entry align="center"><command>INSERT</command>/<command>UPDATE</command>/<command>DELETE</command></entry>
<entry align="center">Tables and foreign tables</entry>
<entry align="center">Tables, views, and foreign tables</entry>
</row>
<row>
<entry align="center"><command>TRUNCATE</></entry>
<entry align="center"><command>TRUNCATE</command></entry>
<entry align="center">&mdash;</entry>
<entry align="center">Tables</entry>
</row>
<row>
<entry align="center" morerows="1"><literal>AFTER</></entry>
<entry align="center"><command>INSERT</>/<command>UPDATE</>/<command>DELETE</></entry>
<entry align="center" morerows="1"><literal>AFTER</literal></entry>
<entry align="center"><command>INSERT</command>/<command>UPDATE</command>/<command>DELETE</command></entry>
<entry align="center">Tables and foreign tables</entry>
<entry align="center">Tables, views, and foreign tables</entry>
</row>
<row>
<entry align="center"><command>TRUNCATE</></entry>
<entry align="center"><command>TRUNCATE</command></entry>
<entry align="center">&mdash;</entry>
<entry align="center">Tables</entry>
</row>
<row>
<entry align="center" morerows="1"><literal>INSTEAD OF</></entry>
<entry align="center"><command>INSERT</>/<command>UPDATE</>/<command>DELETE</></entry>
<entry align="center" morerows="1"><literal>INSTEAD OF</literal></entry>
<entry align="center"><command>INSERT</command>/<command>UPDATE</command>/<command>DELETE</command></entry>
<entry align="center">Views</entry>
<entry align="center">&mdash;</entry>
</row>
<row>
<entry align="center"><command>TRUNCATE</></entry>
<entry align="center"><command>TRUNCATE</command></entry>
<entry align="center">&mdash;</entry>
<entry align="center">&mdash;</entry>
</row>
@@ -152,11 +152,11 @@ CREATE [ CONSTRAINT ] TRIGGER <replaceable class="parameter">name</replaceable>
</informaltable>
<para>
Also, a trigger definition can specify a Boolean <literal>WHEN</>
Also, a trigger definition can specify a Boolean <literal>WHEN</literal>
condition, which will be tested to see whether the trigger should
be fired. In row-level triggers the <literal>WHEN</> condition can
be fired. In row-level triggers the <literal>WHEN</literal> condition can
examine the old and/or new values of columns of the row. Statement-level
triggers can also have <literal>WHEN</> conditions, although the feature
triggers can also have <literal>WHEN</literal> conditions, although the feature
is not so useful for them since the condition cannot refer to any values
in the table.
</para>
@@ -167,36 +167,36 @@ CREATE [ CONSTRAINT ] TRIGGER <replaceable class="parameter">name</replaceable>
</para>
<para>
When the <literal>CONSTRAINT</> option is specified, this command creates a
<firstterm>constraint trigger</>. This is the same as a regular trigger
When the <literal>CONSTRAINT</literal> option is specified, this command creates a
<firstterm>constraint trigger</firstterm>. This is the same as a regular trigger
except that the timing of the trigger firing can be adjusted using
<xref linkend="SQL-SET-CONSTRAINTS">.
Constraint triggers must be <literal>AFTER ROW</> triggers on plain
Constraint triggers must be <literal>AFTER ROW</literal> triggers on plain
tables (not foreign tables). They
can be fired either at the end of the statement causing the triggering
event, or at the end of the containing transaction; in the latter case they
are said to be <firstterm>deferred</>. A pending deferred-trigger firing
are said to be <firstterm>deferred</firstterm>. A pending deferred-trigger firing
can also be forced to happen immediately by using <command>SET
CONSTRAINTS</>. Constraint triggers are expected to raise an exception
CONSTRAINTS</command>. Constraint triggers are expected to raise an exception
when the constraints they implement are violated.
</para>
<para>
The <literal>REFERENCING</> option enables collection
of <firstterm>transition relations</>, which are row sets that include all
The <literal>REFERENCING</literal> option enables collection
of <firstterm>transition relations</firstterm>, which are row sets that include all
of the rows inserted, deleted, or modified by the current SQL statement.
This feature lets the trigger see a global view of what the statement did,
not just one row at a time. This option is only allowed for
an <literal>AFTER</> trigger that is not a constraint trigger; also, if
the trigger is an <literal>UPDATE</> trigger, it must not specify
an <literal>AFTER</literal> trigger that is not a constraint trigger; also, if
the trigger is an <literal>UPDATE</literal> trigger, it must not specify
a <replaceable class="parameter">column_name</replaceable> list.
<literal>OLD TABLE</> may only be specified once, and only for a trigger
that can fire on <literal>UPDATE</> or <literal>DELETE</>; it creates a
transition relation containing the <firstterm>before-images</> of all rows
<literal>OLD TABLE</literal> may only be specified once, and only for a trigger
that can fire on <literal>UPDATE</literal> or <literal>DELETE</literal>; it creates a
transition relation containing the <firstterm>before-images</firstterm> of all rows
updated or deleted by the statement.
Similarly, <literal>NEW TABLE</> may only be specified once, and only for
a trigger that can fire on <literal>UPDATE</> or <literal>INSERT</>;
it creates a transition relation containing the <firstterm>after-images</>
Similarly, <literal>NEW TABLE</literal> may only be specified once, and only for
a trigger that can fire on <literal>UPDATE</literal> or <literal>INSERT</literal>;
it creates a transition relation containing the <firstterm>after-images</firstterm>
of all rows updated or inserted by the statement.
</para>
@@ -225,7 +225,7 @@ CREATE [ CONSTRAINT ] TRIGGER <replaceable class="parameter">name</replaceable>
The name cannot be schema-qualified &mdash; the trigger inherits the
schema of its table. For a constraint trigger, this is also the name to
use when modifying the trigger's behavior using
<command>SET CONSTRAINTS</>.
<command>SET CONSTRAINTS</command>.
</para>
</listitem>
</varlistentry>
@@ -238,7 +238,7 @@ CREATE [ CONSTRAINT ] TRIGGER <replaceable class="parameter">name</replaceable>
<para>
Determines whether the function is called before, after, or instead of
the event. A constraint trigger can only be specified as
<literal>AFTER</>.
<literal>AFTER</literal>.
</para>
</listitem>
</varlistentry>
@@ -261,11 +261,11 @@ CREATE [ CONSTRAINT ] TRIGGER <replaceable class="parameter">name</replaceable>
UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</replaceable> ... ]
</synopsis>
The trigger will only fire if at least one of the listed columns
is mentioned as a target of the <command>UPDATE</> command.
is mentioned as a target of the <command>UPDATE</command> command.
</para>
<para>
<literal>INSTEAD OF UPDATE</> events do not allow a list of columns.
<literal>INSTEAD OF UPDATE</literal> events do not allow a list of columns.
A column list cannot be specified when requesting transition relations,
either.
</para>
@@ -352,7 +352,7 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
once for every row affected by the trigger event, or just once
per SQL statement. If neither is specified, <literal>FOR EACH
STATEMENT</literal> is the default. Constraint triggers can only
be specified <literal>FOR EACH ROW</>.
be specified <literal>FOR EACH ROW</literal>.
</para>
</listitem>
</varlistentry>
@@ -362,20 +362,20 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
<listitem>
<para>
A Boolean expression that determines whether the trigger function
will actually be executed. If <literal>WHEN</> is specified, the
will actually be executed. If <literal>WHEN</literal> is specified, the
function will only be called if the <replaceable
class="parameter">condition</replaceable> returns <literal>true</>.
In <literal>FOR EACH ROW</literal> triggers, the <literal>WHEN</>
class="parameter">condition</replaceable> returns <literal>true</literal>.
In <literal>FOR EACH ROW</literal> triggers, the <literal>WHEN</literal>
condition can refer to columns of the old and/or new row values
by writing <literal>OLD.<replaceable
class="parameter">column_name</replaceable></literal> or
<literal>NEW.<replaceable
class="parameter">column_name</replaceable></literal> respectively.
Of course, <literal>INSERT</> triggers cannot refer to <literal>OLD</>
and <literal>DELETE</> triggers cannot refer to <literal>NEW</>.
Of course, <literal>INSERT</literal> triggers cannot refer to <literal>OLD</literal>
and <literal>DELETE</literal> triggers cannot refer to <literal>NEW</literal>.
</para>
<para><literal>INSTEAD OF</> triggers do not support <literal>WHEN</>
<para><literal>INSTEAD OF</literal> triggers do not support <literal>WHEN</literal>
conditions.
</para>
@@ -385,7 +385,7 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
</para>
<para>
Note that for constraint triggers, evaluation of the <literal>WHEN</>
Note that for constraint triggers, evaluation of the <literal>WHEN</literal>
condition is not deferred, but occurs immediately after the row update
operation is performed. If the condition does not evaluate to true then
the trigger is not queued for deferred execution.
@@ -398,7 +398,7 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
<listitem>
<para>
A user-supplied function that is declared as taking no arguments
and returning type <literal>trigger</>, which is executed when
and returning type <literal>trigger</literal>, which is executed when
the trigger fires.
</para>
</listitem>
@@ -438,32 +438,32 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
<para>
A column-specific trigger (one defined using the <literal>UPDATE OF
<replaceable>column_name</replaceable></literal> syntax) will fire when any
of its columns are listed as targets in the <command>UPDATE</>
command's <literal>SET</> list. It is possible for a column's value
of its columns are listed as targets in the <command>UPDATE</command>
command's <literal>SET</literal> list. It is possible for a column's value
to change even when the trigger is not fired, because changes made to the
row's contents by <literal>BEFORE UPDATE</> triggers are not considered.
Conversely, a command such as <literal>UPDATE ... SET x = x ...</>
will fire a trigger on column <literal>x</>, even though the column's
row's contents by <literal>BEFORE UPDATE</literal> triggers are not considered.
Conversely, a command such as <literal>UPDATE ... SET x = x ...</literal>
will fire a trigger on column <literal>x</literal>, even though the column's
value did not change.
</para>
<para>
In a <literal>BEFORE</> trigger, the <literal>WHEN</> condition is
In a <literal>BEFORE</literal> trigger, the <literal>WHEN</literal> condition is
evaluated just before the function is or would be executed, so using
<literal>WHEN</> is not materially different from testing the same
<literal>WHEN</literal> is not materially different from testing the same
condition at the beginning of the trigger function. Note in particular
that the <literal>NEW</> row seen by the condition is the current value,
as possibly modified by earlier triggers. Also, a <literal>BEFORE</>
trigger's <literal>WHEN</> condition is not allowed to examine the
system columns of the <literal>NEW</> row (such as <literal>oid</>),
that the <literal>NEW</literal> row seen by the condition is the current value,
as possibly modified by earlier triggers. Also, a <literal>BEFORE</literal>
trigger's <literal>WHEN</literal> condition is not allowed to examine the
system columns of the <literal>NEW</literal> row (such as <literal>oid</literal>),
because those won't have been set yet.
</para>
<para>
In an <literal>AFTER</> trigger, the <literal>WHEN</> condition is
In an <literal>AFTER</literal> trigger, the <literal>WHEN</literal> condition is
evaluated just after the row update occurs, and it determines whether an
event is queued to fire the trigger at the end of statement. So when an
<literal>AFTER</> trigger's <literal>WHEN</> condition does not return
<literal>AFTER</literal> trigger's <literal>WHEN</literal> condition does not return
true, it is not necessary to queue an event nor to re-fetch the row at end
of statement. This can result in significant speedups in statements that
modify many rows, if the trigger only needs to be fired for a few of the
@@ -473,7 +473,7 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
<para>
In some cases it is possible for a single SQL command to fire more than
one kind of trigger. For instance an <command>INSERT</command> with
an <literal>ON CONFLICT DO UPDATE</> clause may cause both insert and
an <literal>ON CONFLICT DO UPDATE</literal> clause may cause both insert and
update operations, so it will fire both kinds of triggers as needed.
The transition relations supplied to triggers are
specific to their event type; thus an <command>INSERT</command> trigger
@@ -483,14 +483,14 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
<para>
Row updates or deletions caused by foreign-key enforcement actions, such
as <literal>ON UPDATE CASCADE</> or <literal>ON DELETE SET NULL</>, are
as <literal>ON UPDATE CASCADE</literal> or <literal>ON DELETE SET NULL</literal>, are
treated as part of the SQL command that caused them (note that such
actions are never deferred). Relevant triggers on the affected table will
be fired, so that this provides another way in which a SQL command might
fire triggers not directly matching its type. In simple cases, triggers
that request transition relations will see all changes caused in their
table by a single original SQL command as a single transition relation.
However, there are cases in which the presence of an <literal>AFTER ROW</>
However, there are cases in which the presence of an <literal>AFTER ROW</literal>
trigger that requests transition relations will cause the foreign-key
enforcement actions triggered by a single SQL command to be split into
multiple steps, each with its own transition relation(s). In such cases,
@@ -516,10 +516,10 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
<para>
In <productname>PostgreSQL</productname> versions before 7.3, it was
necessary to declare trigger functions as returning the placeholder
type <type>opaque</>, rather than <type>trigger</>. To support loading
of old dump files, <command>CREATE TRIGGER</> will accept a function
declared as returning <type>opaque</>, but it will issue a notice and
change the function's declared return type to <type>trigger</>.
type <type>opaque</type>, rather than <type>trigger</type>. To support loading
of old dump files, <command>CREATE TRIGGER</command> will accept a function
declared as returning <type>opaque</type>, but it will issue a notice and
change the function's declared return type to <type>trigger</type>.
</para>
</refsect1>
@@ -527,8 +527,8 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
<title>Examples</title>
<para>
Execute the function <function>check_account_update</> whenever
a row of the table <literal>accounts</> is about to be updated:
Execute the function <function>check_account_update</function> whenever
a row of the table <literal>accounts</literal> is about to be updated:
<programlisting>
CREATE TRIGGER check_update
@@ -537,8 +537,8 @@ CREATE TRIGGER check_update
EXECUTE PROCEDURE check_account_update();
</programlisting>
The same, but only execute the function if column <literal>balance</>
is specified as a target in the <command>UPDATE</> command:
The same, but only execute the function if column <literal>balance</literal>
is specified as a target in the <command>UPDATE</command> command:
<programlisting>
CREATE TRIGGER check_update
@@ -547,7 +547,7 @@ CREATE TRIGGER check_update
EXECUTE PROCEDURE check_account_update();
</programlisting>
This form only executes the function if column <literal>balance</>
This form only executes the function if column <literal>balance</literal>
has in fact changed value:
<programlisting>
@@ -558,7 +558,7 @@ CREATE TRIGGER check_update
EXECUTE PROCEDURE check_account_update();
</programlisting>
Call a function to log updates of <literal>accounts</>, but only if
Call a function to log updates of <literal>accounts</literal>, but only if
something changed:
<programlisting>
@@ -569,7 +569,7 @@ CREATE TRIGGER log_update
EXECUTE PROCEDURE log_account_update();
</programlisting>
Execute the function <function>view_insert_row</> for each row to insert
Execute the function <function>view_insert_row</function> for each row to insert
rows into the tables underlying a view:
<programlisting>
@@ -579,8 +579,8 @@ CREATE TRIGGER view_insert
EXECUTE PROCEDURE view_insert_row();
</programlisting>
Execute the function <function>check_transfer_balances_to_zero</> for each
statement to confirm that the <literal>transfer</> rows offset to a net of
Execute the function <function>check_transfer_balances_to_zero</function> for each
statement to confirm that the <literal>transfer</literal> rows offset to a net of
zero:
<programlisting>
@@ -591,7 +591,7 @@ CREATE TRIGGER transfer_insert
EXECUTE PROCEDURE check_transfer_balances_to_zero();
</programlisting>
Execute the function <function>check_matching_pairs</> for each row to
Execute the function <function>check_matching_pairs</function> for each row to
confirm that changes are made to matching pairs at the same time (by the
same statement):
@@ -624,27 +624,27 @@ CREATE TRIGGER paired_items_update
<para>
The <command>CREATE TRIGGER</command> statement in
<productname>PostgreSQL</productname> implements a subset of the
<acronym>SQL</> standard. The following functionalities are currently
<acronym>SQL</acronym> standard. The following functionalities are currently
missing:
<itemizedlist>
<listitem>
<para>
While transition table names for <literal>AFTER</> triggers are
specified using the <literal>REFERENCING</> clause in the standard way,
the row variables used in <literal>FOR EACH ROW</> triggers may not be
specified in a <literal>REFERENCING</> clause. They are available in a
While transition table names for <literal>AFTER</literal> triggers are
specified using the <literal>REFERENCING</literal> clause in the standard way,
the row variables used in <literal>FOR EACH ROW</literal> triggers may not be
specified in a <literal>REFERENCING</literal> clause. They are available in a
manner that is dependent on the language in which the trigger function
is written, but is fixed for any one language. Some languages
effectively behave as though there is a <literal>REFERENCING</> clause
containing <literal>OLD ROW AS OLD NEW ROW AS NEW</>.
effectively behave as though there is a <literal>REFERENCING</literal> clause
containing <literal>OLD ROW AS OLD NEW ROW AS NEW</literal>.
</para>
</listitem>
<listitem>
<para>
The standard allows transition tables to be used with
column-specific <literal>UPDATE</> triggers, but then the set of rows
column-specific <literal>UPDATE</literal> triggers, but then the set of rows
that should be visible in the transition tables depends on the
trigger's column list. This is not currently implemented by
<productname>PostgreSQL</productname>.
@@ -673,7 +673,7 @@ CREATE TRIGGER paired_items_update
<para>
SQL specifies that <literal>BEFORE DELETE</literal> triggers on cascaded
deletes fire <emphasis>after</> the cascaded <literal>DELETE</> completes.
deletes fire <emphasis>after</emphasis> the cascaded <literal>DELETE</literal> completes.
The <productname>PostgreSQL</productname> behavior is for <literal>BEFORE
DELETE</literal> to always fire before the delete action, even a cascading
one. This is considered more consistent. There is also nonstandard
@@ -685,19 +685,19 @@ CREATE TRIGGER paired_items_update
<para>
The ability to specify multiple actions for a single trigger using
<literal>OR</literal> is a <productname>PostgreSQL</> extension of
<literal>OR</literal> is a <productname>PostgreSQL</productname> extension of
the SQL standard.
</para>
<para>
The ability to fire triggers for <command>TRUNCATE</command> is a
<productname>PostgreSQL</> extension of the SQL standard, as is the
<productname>PostgreSQL</productname> extension of the SQL standard, as is the
ability to define statement-level triggers on views.
</para>
<para>
<command>CREATE CONSTRAINT TRIGGER</command> is a
<productname>PostgreSQL</productname> extension of the <acronym>SQL</>
<productname>PostgreSQL</productname> extension of the <acronym>SQL</acronym>
standard.
</para>