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Case-insensitive text type for PostgreSQL
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CITEXT Data Type 2.00 ===================== This distribution creates a custom PostgreSQL data type, CITEXT, a locale- aware, case-insensitve TEXT type for PostgreSQL 8.3. Essentially, it internally calls `LOWER()` when comparing values. Otherwise, it behaves exactly like TEXT. The standard approach to doing case-insensitive matches in PostgreSQL has been to use the `LOWER()` function in your queries, something like this: SELECT * FROM tab WHERE lower(col) = LOWER(?); This works reasonably well, but has a number of drawbacks: * It makes your SQL statements verbose, and you always have to remember to use `LOWER()` on both the column and on the query value (so that both use the same collations). * It won't use an index, unless you create a functional index using `LOWER()`. * You can't have a case-insensitive primary key without creating two unique indexes, one for the primary key (implicitly created) and a functional index using `LOWER()`. The CITEXT data type allows you to replace all the calls to `LOWER()` in client code that wants to perform case-insensitive queries, while also allowing a primary key to be case-insensitive. CITEXT is multibyte aware, just like TEXT, which means that the comparison of uppercase and lowercase characters is dependent on the rules in the `LC_COLLATE` locale setting. Again, this behavior is identical to the use of `LOWER()` in queries. But because it's done in C and is transparent, you don't have to remember to do anything special in your queries. Installation ------------ To install the CITEXT data type, make sure that pg_xs is in your path, and then type these commands: export USE_PGXS=1 make make install make installcheck If you encounter an error such as: "Makefile", line 8: Need an operator You need to use GNU make, which may well be installed on your system as 'gmake': gmake gmake install gmake installcheck If you encounter an error such as: make: pg_config: Command not found Be sure that you have pg_config installed and in your path. If you used a package management system such as RPM to install PostgreSQL, be sure that the -devel package is also installed. If necessary, add the path to pg_config to your $PATH environment variable: export PATH=$PATH:/path/to/pgsql/bin make make install make installcheck And finally, if all that fails, copy the entire distribution directory to the 'contrib' subdirectory of the PostgreSQL source code and try it there using these commands: make make install make installcheck Note that the tests run by the `installcheck` target expect the locale to be en_US.UTF-8, so there could potentially be some failures if you're using a different locale. Once everything is installed, go ahead and add the citext data type to your database: psql -f citext.sql [db_name] Usage ----- Once you've installed the CITEXT data type, you can start using it in your database. CREATE TABLE users ( nick CITEXT, pass TEXT ); INSERT INTO users VALUES ( 'larry', md5(random()::text) ); INSERT INTO users VALUES ( 'Tom', md5(random()::text) ); INSERT INTO users VALUES ( 'Damian', md5(random()::text) ); INSERT INTO users VALUES ( 'NEAL', md5(random()::text) ); INSERT INTO users VALUES ( 'Bjørn', md5(random()::text) ); INSERT INTO users VALUES ( '☺唐鳳☻', md5(random()::text) ); If you ever need to install the data type into another database, you'll find 'citext.sql' in the 'share/contrib' subdirectory of your PostgreSQL server directory. This 'README.citext' file will be in the 'doc/contrib' subdirectory. Suported Platforms ------------------ This package uses PostgreSQL's build tools for easy cross-platform build suport. It is therefore designed to build and install on any platform that supports PostgreSQL. It is known to work on the following platforms and operating systems. * Darwin 9.3.0 i386 If you know of others, please submit them! Use `uname -mrs` to get the formal OS and hardware names. Author ------ David E. Wheeler <email@example.com> Inspired by CITEXT 1.0 by Donald Fraser. Copyright and License --------------------- Copyright (c) 2008 David E. Wheeler. Some rights reserved. Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a written agreement is hereby granted, provided that the above copyright notice and this paragraph and the following two paragraphs appear in all copies. IN NO EVENT SHALL KINETICODE BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF KINETICODE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. KINETICODE SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND KINETICODE HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.