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Improvements to SQL/MED documentation.

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Laurenz Albe, somewhat modified by me.
This commit is contained in:
Robert Haas 2011-07-25 09:37:06 -04:00
parent 7c26395661
commit f5af8eed92
2 changed files with 15 additions and 3 deletions
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14
doc/src/sgml/ddl.sgml
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@ -3008,6 +3008,9 @@ ANALYZE measurement;
<indexterm>
<primary>foreign table</primary>
</indexterm>
<indexterm>
<primary>user mapping</primary>
</indexterm>
<para>
<productname>PostgreSQL</productname> implements portions of the SQL/MED
@ -3037,8 +3040,15 @@ ANALYZE measurement;
tables</firstterm>, which define the structure of the remote data. A
foreign table can be used in queries just like a normal table, but a
foreign table has no storage in the PostgreSQL server. Whenever it is
used, PostgreSQL asks the foreign data wrapper to fetch the data from the
external source.
used, <productname>PostgreSQL</productname> asks the foreign data wrapper
to fetch the data from the external source.
</para>
<para>
Accessing remote data may require authentication at the external
data source. This information can be provided by a
<firstterm>user mapping</>, which can provide additional options based
on the current <productname>PostgreSQL</productname> role.
</para>
<para>

4
doc/src/sgml/fdwhandler.sgml
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@ -152,7 +152,9 @@ BeginForeignScan (ForeignScanState *node,
</programlisting>
Begin executing a foreign scan. This is called during executor startup.
It should perform any initialization needed before the scan can start.
It should perform any initialization needed before the scan can start,
but not start executing the actual scan (that should be done upon the
first call to <function>IterateForeignScan</>).
The <structname>ForeignScanState</> node has already been created, but
its <structfield>fdw_state</> field is still NULL. Information about
the table to scan is accessible through the