Update FAQ.

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Frequently Asked Questions (FAQ) for PostgreSQL Frequently Asked Questions (FAQ) for PostgreSQL
Last updated: Thu Apr 26 20:55:41 EDT 2001 Last updated: Thu May 10 21:32:49 EDT 2001
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
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4.11) What is an R-tree index? 4.11) What is an R-tree index?
4.12) What is the Genetic Query Optimizer? 4.12) What is the Genetic Query Optimizer?
4.13) How do I perform regular expression searches and 4.13) How do I perform regular expression searches and
case-insensitive regular expression searches? case-insensitive regular expression searches? How do I use an index
for case-insensitive searches?
4.14) In a query, how do I detect if a field is NULL? 4.14) In a query, how do I detect if a field is NULL?
4.15) What is the difference between the various character types? 4.15) What is the difference between the various character types?
4.16.1) How do I create a serial/auto-incrementing field? 4.16.1) How do I create a serial/auto-incrementing field?
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1.7) What is the latest release? 1.7) What is the latest release?
The latest release of PostgreSQL is version 7.1. The latest release of PostgreSQL is version 7.1.1.
We plan to have major releases every four months. We plan to have major releases every four months.
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join queries through nonexhaustive search. join queries through nonexhaustive search.
4.13) How do I perform regular expression searches and case-insensitive 4.13) How do I perform regular expression searches and case-insensitive
regular expression searches? regular expression searches? How do I use an index for case-insensitive
searches?
The ~ operator does regular expression matching, and ~* does The ~ operator does regular expression matching, and ~* does
case-insensitive regular expression matching. The case-insensitive case-insensitive regular expression matching. The case-insensitive
variant of LIKE is called ILIKE in PostgreSQL 7.1 and later. variant of LIKE is called ILIKE in PostgreSQL 7.1 and later.
Case-insensitive equality comparisons are normally expressed as:
SELECT *
FROM tab
WHERE lower(col) = 'abc'
This will not use an standard index. However, if you create a
functional index, it will be used:
CREATE INDEX tabindex on tab (lower(col));
4.14) In a query, how do I detect if a field is NULL? 4.14) In a query, how do I detect if a field is NULL?
You test the column with IS NULLIS NOT NULL. You test the column with IS NULLIS NOT NULL.

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<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1> <H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
<P>Last updated: Thu Apr 26 20:55:41 EDT 2001</P> <P>Last updated: Thu May 10 21:32:49 EDT 2001</P>
<P>Current maintainer: Bruce Momjian (<A href= <P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR> "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
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<H4><A name="1.7">1.7</A>) What is the latest release?</H4> <H4><A name="1.7">1.7</A>) What is the latest release?</H4>
<P>The latest release of PostgreSQL is version 7.1.</P> <P>The latest release of PostgreSQL is version 7.1.1.</P>
<P>We plan to have major releases every four months.</P> <P>We plan to have major releases every four months.</P>