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Update FDW docs to reflect existence of CHECK constraints.

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Generalize the remarks previously made about NOT NULL constraints to
CHECK constraints.

Etsuro Fujita
This commit is contained in:
Robert Haas 2015-04-21 17:46:47 -04:00
parent 060a1224af
commit 0275ecf31c
1 changed files with 7 additions and 7 deletions
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14
doc/src/sgml/fdwhandler.sgml
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@ -242,13 +242,13 @@ IterateForeignScan (ForeignScanState *node);
<para>
Note that <productname>PostgreSQL</productname>'s executor doesn't care
whether the rows returned violate any <literal>NOT NULL</literal>
constraints that were defined on the foreign table columns &mdash; but
the planner does care, and may optimize queries incorrectly if
<literal>NULL</> values are present in a column declared not to contain
them. If a <literal>NULL</> value is encountered when the user has
declared that none should be present, it may be appropriate to raise an
error (just as you would need to do in the case of a data type mismatch).
whether the rows returned violate any constraints that were defined on
the foreign table &mdash; but the planner does care, and may optimize
queries incorrectly if there are rows visible in the foreign table that
do not satisfy a declared constraint. If a constraint is violated when
the user has declared that the constraint should hold true, it may be
appropriate to raise an error (just as you would need to do in the case
of a data type mismatch).
</para>
<para>