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Fix up foreign-key mechanism so that there is a sound semantic basis for the

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equality checks it applies, instead of a random dependence on whatever
operators might be named "=".  The equality operators will now be selected
from the opfamily of the unique index that the FK constraint depends on to
enforce uniqueness of the referenced columns; therefore they are certain to be
consistent with that index's notion of equality.  Among other things this
should fix the problem noted awhile back that pg_dump may fail for foreign-key
constraints on user-defined types when the required operators aren't in the
search path.  This also means that the former warning condition about "foreign
key constraint will require costly sequential scans" is gone: if the
comparison condition isn't indexable then we'll reject the constraint
entirely. All per past discussions.

Along the way, make the RI triggers look into pg_constraint for their
information, instead of using pg_trigger.tgargs; and get rid of the always
error-prone fixed-size string buffers in ri_triggers.c in favor of building up
the RI queries in StringInfo buffers.

initdb forced due to columns added to pg_constraint and pg_trigger.
This commit is contained in:
Tom Lane
2007-02-14 01:58:58 +00:00
parent 65e2f55031
commit 7bddca3450
33 changed files with 1731 additions and 1665 deletions
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58
doc/src/sgml/catalogs.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.144 2007/01/31 20:56:16 momjian Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/catalogs.sgml,v 2.145 2007/02/14 01:58:55 tgl Exp $ -->
<!--
Documentation of the system catalogs, directed toward PostgreSQL developers
-->
@ -1870,6 +1870,27 @@
<entry>If a foreign key, list of the referenced columns</entry>
</row>
<row>
<entry><structfield>conpfeqop</structfield></entry>
<entry><type>oid[]</type></entry>
<entry><literal><link linkend="catalog-pg-operator"><structname>pg_operator</structname></link>.oid</></entry>
<entry>If a foreign key, list of the equality operators for PK = FK comparisons</entry>
</row>
<row>
<entry><structfield>conppeqop</structfield></entry>
<entry><type>oid[]</type></entry>
<entry><literal><link linkend="catalog-pg-operator"><structname>pg_operator</structname></link>.oid</></entry>
<entry>If a foreign key, list of the equality operators for PK = PK comparisons</entry>
</row>
<row>
<entry><structfield>conffeqop</structfield></entry>
<entry><type>oid[]</type></entry>
<entry><literal><link linkend="catalog-pg-operator"><structname>pg_operator</structname></link>.oid</></entry>
<entry>If a foreign key, list of the equality operators for FK = FK comparisons</entry>
</row>
<row>
<entry><structfield>conbin</structfield></entry>
<entry><type>text</type></entry>
@ -1899,8 +1920,8 @@
<note>
<para>
<literal>pg_class.relchecks</literal> needs to agree with the
number of check-constraint entries found in this table for the
given relation.
number of check-constraint entries found in this table for each
relation.
</para>
</note>
@ -4166,35 +4187,42 @@
<entry><structfield>tgisconstraint</structfield></entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>True if trigger implements a referential integrity constraint</entry>
<entry>True if trigger is a <quote>constraint trigger</></entry>
</row>
<row>
<entry><structfield>tgconstrname</structfield></entry>
<entry><type>name</type></entry>
<entry></entry>
<entry>Referential integrity constraint name</entry>
<entry>Constraint name, if a constraint trigger</entry>
</row>
<row>
<entry><structfield>tgconstrrelid</structfield></entry>
<entry><type>oid</type></entry>
<entry><literal><link linkend="catalog-pg-class"><structname>pg_class</structname></link>.oid</literal></entry>
<entry>The table referenced by an referential integrity constraint</entry>
<entry>The table referenced by a referential integrity constraint</entry>
</row>
<row>
<entry><structfield>tgconstraint</structfield></entry>
<entry><type>oid</type></entry>
<entry><literal><link linkend="catalog-pg-constraint"><structname>pg_constraint</structname></link>.oid</literal></entry>
<entry>The <structname>pg_constraint</> entry owning the trigger, if any</entry>
</row>
<row>
<entry><structfield>tgdeferrable</structfield></entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>True if deferrable</entry>
<entry>True if constraint trigger is deferrable</entry>
</row>
<row>
<entry><structfield>tginitdeferred</structfield></entry>
<entry><type>bool</type></entry>
<entry></entry>
<entry>True if initially deferred</entry>
<entry>True if constraint trigger is initially deferred</entry>
</row>
<row>
@ -4221,10 +4249,22 @@
</tgroup>
</table>
<note>
<para>
When <structfield>tgconstraint</> is nonzero,
<structfield>tgisconstraint</> must be true, and
<structfield>tgconstrname</>, <structfield>tgconstrrelid</>,
<structfield>tgdeferrable</>, <structfield>tginitdeferred</> are redundant
with the referenced <structname>pg_constraint</> entry. The reason we
keep these fields is that we support <quote>stand-alone</> constraint
triggers with no corresponding <structname>pg_constraint</> entry.
</para>
</note>
<note>
<para>
<literal>pg_class.reltriggers</literal> needs to agree with the
number of triggers found in this table for the given relation.
number of triggers found in this table for each relation.
</para>
</note>

3
doc/src/sgml/trigger.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/trigger.sgml,v 1.49 2007/02/01 00:28:18 momjian Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/trigger.sgml,v 1.50 2007/02/14 01:58:56 tgl Exp $ -->
<chapter id="triggers">
<title>Triggers</title>
@ -467,6 +467,7 @@ typedef struct Trigger
bool tgenabled;
bool tgisconstraint;
Oid tgconstrrelid;
Oid tgconstraint;
bool tgdeferrable;
bool tginitdeferred;
int16 tgnargs;