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Update rule examples

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This commit is contained in:
Bruce Momjian 2000-04-07 17:35:08 +00:00
parent d27a566583
commit 592b69056d
1 changed files with 23 additions and 13 deletions
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36
doc/src/sgml/ref/create_rule.sgml
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@ -1,5 +1,5 @@
<!--
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_rule.sgml,v 1.11 2000/04/07 17:23:11 momjian Exp $
$Header: /cvsroot/pgsql/doc/src/sgml/ref/create_rule.sgml,v 1.12 2000/04/07 17:35:08 momjian Exp $
Postgres documentation
-->
@ -171,12 +171,14 @@ CREATE
two rules have the same semantics:
<programlisting>
ON UPDATE TO emp.salary WHERE emp.name = "Joe"
DO UPDATE emp ( ... ) WHERE ...
DO
UPDATE emp ( ... ) WHERE ...
</programlisting>
<programlisting>
ON UPDATE TO emp-1.salary WHERE emp-2.name = "Joe"
DO UPDATE emp-3 ( ... ) WHERE ...
DO
UPDATE emp-3 ( ... ) WHERE ...
</programlisting>
Each rule can have the optional tag INSTEAD.
@ -203,13 +205,15 @@ ON UPDATE TO emp-1.salary WHERE emp-2.name = "Joe"
<programlisting>
CREATE RULE bad_rule_combination_1 AS
ON SELECT TO emp
DO INSTEAD SELECT TO toyemp;
DO INSTEAD
SELECT TO toyemp;
</programlisting>
<programlisting>
CREATE RULE bad_rule_combination_2 AS
ON SELECT TO toyemp
DO INSTEAD SELECT TO emp;
DO INSTEAD
SELECT TO emp;
</programlisting>
<para>
This attempt to retrieve from EMP will cause
@ -257,8 +261,10 @@ SELECT * FROM emp;
<programlisting>
CREATE RULE example_1 AS
ON UPDATE emp.salary WHERE current.name = "Joe"
DO UPDATE emp (salary = new.salary)
WHERE emp.name = "Sam";
DO
UPDATE emp
SET salary = new.salary
WHERE emp.name = "Sam";
</programlisting>
At the time Joe receives a salary adjustment, the event
@ -275,8 +281,9 @@ CREATE RULE example_2 AS
ON SELECT TO EMP.salary
WHERE current.name = "Bill"
DO INSTEAD
SELECT (emp.salary) from emp
WHERE emp.name = "Joe";
SELECT emp.salary
FROM emp
WHERE emp.name = "Joe";
</programlisting>
</para>
<para>
@ -285,8 +292,9 @@ CREATE RULE example_2 AS
the current user):
<programlisting>
CREATE RULE example_3 AS
ON SELECT TO emp.salary
WHERE current.dept = "shoe" AND current_user = "Joe"
ON
SELECT TO emp.salary
WHERE current.dept = "shoe" AND current_user = "Joe"
DO INSTEAD NOTHING;
</programlisting>
</para>
@ -298,7 +306,8 @@ CREATE toyemp(name = char16, salary = int4);
CREATE RULE example_4 AS
ON SELECT TO toyemp
DO INSTEAD
SELECT (emp.name, emp.salary) FROM emp
SELECT (emp.name, emp.salary)
FROM emp
WHERE emp.dept = "toy";
</programlisting>
</para>
@ -307,7 +316,8 @@ CREATE RULE example_4 AS
<programlisting>
CREATE RULE example_5 AS
ON INERT TO emp WHERE new.salary > 5000
DO UPDATE NEWSET salary = 5000;
DO
UPDATE NEWSET salary = 5000;
</programlisting>
</para>
</refsect1>