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Postgres FD Implementation
Commit b47953f9 authored by Alvaro Herrera's avatar Alvaro Herrera
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Merge docs for CREATE CONSTRAINT TRIGGER and CREATE TRIGGER

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doc/src/sgml/ref/allfiles.sgml
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......@@ -46,7 +46,6 @@ Complete list of usable sgml source files in this directory.
<!entity copyTable system "copy.sgml">
<!entity createAggregate system "create_aggregate.sgml">
<!entity createCast system "create_cast.sgml">
<!entity createConstraint system "create_constraint.sgml">
<!entity createConversion system "create_conversion.sgml">
<!entity createDatabase system "create_database.sgml">
<!entity createDomain system "create_domain.sgml">
......
doc/src/sgml/ref/create_constraint.sgml deleted 100644 → 0
View file @ 0de92fd1
<!--
doc/src/sgml/ref/create_constraint.sgml
PostgreSQL documentation
-->
<refentry id="SQL-CREATECONSTRAINT">
<refmeta>
<refentrytitle>CREATE CONSTRAINT TRIGGER</refentrytitle>
<manvolnum>7</manvolnum>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>CREATE CONSTRAINT TRIGGER</refname>
<refpurpose>define a new constraint trigger</refpurpose>
</refnamediv>
<indexterm zone="sql-createconstraint">
<primary>CREATE CONSTRAINT TRIGGER</primary>
</indexterm>
<refsynopsisdiv>
<synopsis>
CREATE CONSTRAINT TRIGGER <replaceable class="parameter">name</replaceable>
AFTER <replaceable class="parameter">event</replaceable> [ OR ... ]
ON <replaceable class="parameter">table_name</replaceable>
[ FROM <replaceable class="parameter">referenced_table_name</replaceable> ]
{ NOT DEFERRABLE | [ DEFERRABLE ] { INITIALLY IMMEDIATE | INITIALLY DEFERRED } }
FOR EACH ROW
[ WHEN ( <replaceable class="parameter">condition</replaceable> ) ]
EXECUTE PROCEDURE <replaceable class="parameter">function_name</replaceable> ( <replaceable class="parameter">arguments</replaceable> )
</synopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>CREATE CONSTRAINT TRIGGER</command> creates a
<firstterm>constraint trigger</>. 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. 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 can
also be forced to happen immediately by using <command>SET CONSTRAINTS</>.
</para>
</refsect1>
<refsect1>
<title>Parameters</title>
<variablelist>
<varlistentry>
<term><replaceable class="PARAMETER">name</replaceable></term>
<listitem>
<para>
The name of the constraint trigger. This is also the name to use
when modifying the trigger's behavior using <command>SET CONSTRAINTS</>.
The name cannot be schema-qualified &mdash; the trigger inherits the
schema of its table.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">event</replaceable></term>
<listitem>
<para>
One of <literal>INSERT</literal>, <literal>UPDATE</literal>, or
<literal>DELETE</literal>; this specifies the event that will fire the
trigger. Multiple events can be specified using <literal>OR</literal>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">table_name</replaceable></term>
<listitem>
<para>
The (possibly schema-qualified) name of the table in which
the triggering events occur.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">referenced_table_name</replaceable></term>
<listitem>
<para>
The (possibly schema-qualified) name of another table referenced by the
constraint. This option is used for foreign-key constraints and is not
recommended for general use.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>DEFERRABLE</literal></term>
<term><literal>NOT DEFERRABLE</literal></term>
<term><literal>INITIALLY IMMEDIATE</literal></term>
<term><literal>INITIALLY DEFERRED</literal></term>
<listitem>
<para>
The default timing of the trigger.
See the <xref linkend="SQL-CREATETABLE">
documentation for details of these constraint options.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">condition</replaceable></term>
<listitem>
<para>
A Boolean expression that determines whether the trigger function
will actually be executed. This acts the same as in <xref
linkend="SQL-CREATETRIGGER">.
Note in particular that evaluation of the <literal>WHEN</>
condition is not deferred, but occurs immediately after the row
update operation is performed. If the condition does not evaluate
to <literal>true</> then the trigger is not queued for deferred
execution.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">function_name</replaceable></term>
<listitem>
<para>
The function to call when the trigger is fired. See <xref
linkend="SQL-CREATETRIGGER"> for
details.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">arguments</replaceable></term>
<listitem>
<para>
Optional argument strings to pass to the trigger function. See <xref
linkend="SQL-CREATETRIGGER"> for
details.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
<command>CREATE CONSTRAINT TRIGGER</command> is a
<productname>PostgreSQL</productname> extension of the <acronym>SQL</>
standard.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="sql-createtrigger"></member>
<member><xref linkend="sql-droptrigger"></member>
<member><xref linkend="sql-set-constraints"></member>
</simplelist>
</refsect1>
</refentry>
doc/src/sgml/ref/create_trigger.sgml
View file @ b47953f9
......@@ -21,8 +21,10 @@ PostgreSQL documentation
<refsynopsisdiv>
<synopsis>
CREATE TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFORE | AFTER | INSTEAD OF } { <replaceable class="PARAMETER">event</replaceable> [ OR ... ] }
CREATE [ CONSTRAINT ] TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFORE | AFTER | INSTEAD OF } { <replaceable class="PARAMETER">event</replaceable> [ OR ... ] }
ON <replaceable class="PARAMETER">table</replaceable> [ FOR [ EACH ] { ROW | STATEMENT } ]
[ FROM <replaceable class="parameter">referenced_table_name</replaceable> ]
{ NOT DEFERRABLE | [ DEFERRABLE ] { INITIALLY IMMEDIATE | INITIALLY DEFERRED } }
[ WHEN ( <replaceable class="parameter">condition</replaceable> ) ]
EXECUTE PROCEDURE <replaceable class="PARAMETER">function_name</replaceable> ( <replaceable class="PARAMETER">arguments</replaceable> )
</synopsis>
......@@ -149,6 +151,20 @@ CREATE TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFORE | AFTE
they will be fired in alphabetical order by name.
</para>
<para>
When the <literal>CONSTRAINT</> option is specified, this command creates a
<firstterm>constraint trigger</>. 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. 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 can
also be forced to happen immediately by using <command>SET CONSTRAINTS</>.
Constraint triggers are expected to raise an exception when the constraints
they implement are violated.
</para>
<para>
<command>SELECT</command> does not modify any rows so you cannot
create <command>SELECT</command> triggers. Rules and views are more
......@@ -170,6 +186,10 @@ CREATE TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFORE | AFTE
<para>
The name to give the new trigger. This must be distinct from
the name of any other trigger for the same table.
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</>.
</para>
</listitem>
</varlistentry>
......@@ -181,7 +201,8 @@ CREATE TRIGGER <replaceable class="PARAMETER">name</replaceable> { BEFORE | AFTE
<listitem>
<para>
Determines whether the function is called before, after, or instead of
the event.
the event. A constraint trigger can only be specified as
<literal>AFTER</>.
</para>
</listitem>
</varlistentry>
......@@ -222,6 +243,33 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="PARAMETER">referenced_table_name</replaceable></term>
<listitem>
<para>
The (possibly schema-qualified) name of another table referenced by the
constraint. This option is used for foreign-key constraints and is not
recommended for general use. This can only be specified for
constraint triggers.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>DEFERRABLE</literal></term>
<term><literal>NOT DEFERRABLE</literal></term>
<term><literal>INITIALLY IMMEDIATE</literal></term>
<term><literal>INITIALLY DEFERRED</literal></term>
<listitem>
<para>
The default timing of the trigger.
See the <xref linkend="SQL-CREATETABLE"> documentation for details of
these constraint options. This can only be specified for constraint
triggers.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><literal>FOR EACH ROW</literal></term>
<term><literal>FOR EACH STATEMENT</literal></term>
......@@ -231,7 +279,8 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
This specifies whether the trigger procedure should be fired
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.
STATEMENT</literal> is the default. Constraint triggers can only
be specified <literal>FOR EACH ROW</>.
</para>
</listitem>
</varlistentry>
......@@ -263,6 +312,13 @@ UPDATE OF <replaceable>column_name1</replaceable> [, <replaceable>column_name2</
Currently, <literal>WHEN</literal> expressions cannot contain
subqueries.
</para>
<para>
Note that for constraint triggers, evaluation of the <literal>WHEN</>
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.
</para>
</listitem>
</varlistentry>
......@@ -481,6 +537,12 @@ CREATE TRIGGER view_insert
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</>
standard.
</para>
</refsect1>
<refsect1>
......@@ -490,6 +552,7 @@ CREATE TRIGGER view_insert
<member><xref linkend="sql-createfunction"></member>
<member><xref linkend="sql-altertrigger"></member>
<member><xref linkend="sql-droptrigger"></member>
<member><xref linkend="sql-set-constraints"></member>
</simplelist>
</refsect1>
</refentry>
doc/src/sgml/reference.sgml
View file @ b47953f9
......@@ -74,7 +74,6 @@
&copyTable;
&createAggregate;
&createCast;
&createConstraint;
&createConversion;
&createDatabase;
&createDomain;
......
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