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@ -1,7 +1,7 @@ |
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Frequently Asked Questions (FAQ) for PostgreSQL |
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Last updated: Thu Apr 26 20:55:41 EDT 2001 |
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Last updated: Thu May 10 21:32:49 EDT 2001 |
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Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us) |
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@ -74,7 +74,8 @@ |
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4.11) What is an R-tree index? |
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4.12) What is the Genetic Query Optimizer? |
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4.13) How do I perform regular expression searches and |
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case-insensitive regular expression searches? |
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case-insensitive regular expression searches? How do I use an index |
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for case-insensitive searches? |
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4.14) In a query, how do I detect if a field is NULL? |
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4.15) What is the difference between the various character types? |
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4.16.1) How do I create a serial/auto-incrementing field? |
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@ -233,7 +234,7 @@ |
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1.7) What is the latest release? |
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The latest release of PostgreSQL is version 7.1. |
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The latest release of PostgreSQL is version 7.1.1. |
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We plan to have major releases every four months. |
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@ -751,12 +752,24 @@ Maximum number of indexes on a table? unlimited |
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join queries through nonexhaustive search. |
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4.13) How do I perform regular expression searches and case-insensitive |
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regular expression searches? |
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regular expression searches? How do I use an index for case-insensitive |
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searches? |
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The ~ operator does regular expression matching, and ~* does |
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case-insensitive regular expression matching. The case-insensitive |
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variant of LIKE is called ILIKE in PostgreSQL 7.1 and later. |
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Case-insensitive equality comparisons are normally expressed as: |
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SELECT * |
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FROM tab |
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WHERE lower(col) = 'abc' |
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This will not use an standard index. However, if you create a |
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functional index, it will be used: |
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CREATE INDEX tabindex on tab (lower(col)); |
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4.14) In a query, how do I detect if a field is NULL? |
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You test the column with IS NULLIS NOT NULL. |
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