Martijn van Oosterhout wrote:
-- Start of PGP signed section.
> Hi,
>
> After going through pgsql-general a bit I figured there were a few
> important questions missing from the FAQ, so I wrote some.
>
> Comments welcome. I can write more, if people can suggest things to
> write about. I was thinking something about collation and locales but
> I'm sure sure I understand them myself.
I have updated the FAQ to handle three of the items you mentioned. In
one case, I added a new FAQ entry (double-quoting identifiers with a
link to our docs), and in two other cases (indexing long columns,
case-insensitive columns) I added to existing FAQ items where
appropriate. Patch attached and applied.
For the batch job and single-CPU issues, they did not fit into existing
FAQ entries, and I am not sure they are asked enough to be added as
FAQs. I am interested to hear other's opinions on this.
--
Bruce Momjian | http://candle.pha.pa.us
pgman@xxxxxxxxxxxxxxxx | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073
Index: doc/src/FAQ/FAQ.html
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--- doc/src/FAQ/FAQ.html 10 Aug 2005 19:26:19 -0000
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*** 116,122 ****
does not exist" errors when accessing temporary tables in PL/PgSQL
functions?<BR>
<A href="#4.20">4.20</A>) What replication solutions are available?<BR>
!
<HR>
--- 116,124 ----
does not exist" errors when accessing temporary tables in PL/PgSQL
functions?<BR>
<A href="#4.20">4.20</A>) What replication solutions are available?<BR>
! <A href="#4.21">4.21</A>) Why are my table and column names not
! recognized in my query?<BR>
!
<HR>
***************
*** 613,618 ****
--- 617,628 ----
<P>The maximum table size and maximum number of columns can be
quadrupled by increasing the default block size to 32k.</P>
+ <P>One limitation is that indexes can not be created on columns
+ longer than about 2,000 characters. Fortunately, such indexes are
+ rarely needed. Uniqueness is best guaranteed using another column
+ that is an MD5 hash of the long column, and full text indexing
+ allows for searching of words within the column.</P>
+
<H3><A name="4.5">4.5</A>) How much database disk space is required
to store data from a typical text file?</H3>
***************
*** 740,746 ****
<PRE>
CREATE INDEX tabindex ON tab (lower(col));
</PRE>
!
<H3><A name="4.9">4.9</A>) In a query, how do I detect if a field
is <SMALL>NULL</SMALL>? How can I sort on whether a field is <SMALL>
NULL</SMALL> or not?</H3>
--- 750,761 ----
<PRE>
CREATE INDEX tabindex ON tab (lower(col));
</PRE>
! <P>If the above index is created as <SMALL>UNIQUE</SMALL>, though
! the column can store upper and lowercase characters, it can not have
! identical values that differ only in case. To force a particular
! case to be stored in the column, use a <SMALL>CHECK</SMALL>
! constraint or a trigger.</P>
!
<H3><A name="4.9">4.9</A>) In a query, how do I detect if a field
is <SMALL>NULL</SMALL>? How can I sort on whether a field is <SMALL>
NULL</SMALL> or not?</H3>
***************
*** 1000,1004 ****
--- 1015,1036 ----
<P>There are also commercial and hardware-based replication solutions
available supporting a variety of replication models.</P>
+
+ <H3><A name="4.20">4.20</A>) Why are my table and column names not
+ recognized in my query?</H3>
+
+ <P>The most common cause is the use of double-quotes around table or
+ column names during table creation. When double-quotes are used,
+ table and column names (called identifiers) are stored <a
+ href="http://www.postgresql.org/docs/8.0/static/sql-syntax.html#SQL-
+ SYNTAX-IDENTIFIERS">case-sensitive</a>, meaning you must use
+ double-quotes when referencing the names in a query. Some interfaces,
+ like pgAdmin, automatically double-quote identifiers during table
+ creation. So, for identifiers to be recognized, you must either:
+ <UL>
+ <LI>Avoid double-quoting identifiers when creating tables</LI>
+ <LI>Use only lowercase characters in identifiers</LI>
+ <LI>Double-quote identifiers when referencing them in queries</LI>
+ </UL>
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