postgres

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Magnus Hagander 1f2378b1ea Convert cvsignore to gitignore, and add .gitignore for build targets.		15 years ago
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.gitignore	Convert cvsignore to gitignore, and add .gitignore for build targets.	15 years ago
Makefile	Simplify contrib Makefiles by removing unnecessary SRCS macro,	19 years ago
README.fuzzystrmatch	Update copyright for 2006. Update scripts.	20 years ago
README.soundex	Clean up CREATE FUNCTION syntax usage in contrib and elsewhere, in	20 years ago
dmetaphone.c	Fix bugs in plpgsql and ecpg caused by assuming that isspace() would only	19 years ago
fuzzystrmatch.c	Remove a few baby-C macros in fuzzystrmatch. Add a few missing includes.	19 years ago
fuzzystrmatch.h	Defend against non-ASCII letters in fuzzystrmatch code. The functions	16 years ago
fuzzystrmatch.sql.in	The attached patch implements the soundex difference function which	21 years ago
uninstall_fuzzystrmatch.sql	contrib uninstall scripts	20 years ago

README.soundex

NOTE: Modified August 07, 2001 by Joe Conway. Updated for accuracy
	after combining soundex code into the fuzzystrmatch contrib
---------------------------------------------------------------------
The Soundex system is a method of matching similar sounding names
(or any words) to the same code.  It was initially used by the
United States Census in 1880, 1900, and 1910, but it has little use
beyond English names (or the English pronunciation of names), and
it is not a linguistic tool.

When comparing two soundex values to determine similarity, the
difference function reports how close the match is on a scale
from zero to four, with zero being no match and four being an
exact match.

The following are some usage examples:

SELECT soundex('hello world!');

SELECT soundex('Anne'), soundex('Ann'), difference('Anne', 'Ann');
SELECT soundex('Anne'), soundex('Andrew'), difference('Anne', 'Andrew');
SELECT soundex('Anne'), soundex('Margaret'), difference('Anne', 'Margaret');

CREATE TABLE s (nm text);

INSERT INTO s VALUES ('john');
INSERT INTO s VALUES ('joan');
INSERT INTO s VALUES ('wobbly');
INSERT INTO s VALUES ('jack');

SELECT * FROM s WHERE soundex(nm) = soundex('john');

SELECT a.nm, b.nm FROM s a, s b WHERE soundex(a.nm) = soundex(b.nm) AND a.oid <> b.oid;

CREATE FUNCTION text_sx_eq(text, text) RETURNS boolean AS
'select soundex($1) = soundex($2)'
LANGUAGE SQL;

CREATE FUNCTION text_sx_lt(text, text) RETURNS boolean AS
'select soundex($1) < soundex($2)'
LANGUAGE SQL;

CREATE FUNCTION text_sx_gt(text, text) RETURNS boolean AS
'select soundex($1) > soundex($2)'
LANGUAGE SQL;

CREATE FUNCTION text_sx_le(text, text) RETURNS boolean AS
'select soundex($1) <= soundex($2)'
LANGUAGE SQL;

CREATE FUNCTION text_sx_ge(text, text) RETURNS boolean AS
'select soundex($1) >= soundex($2)'
LANGUAGE SQL;

CREATE FUNCTION text_sx_ne(text, text) RETURNS boolean AS
'select soundex($1) <> soundex($2)'
LANGUAGE SQL;

DROP OPERATOR #= (text, text);

CREATE OPERATOR #= (leftarg=text, rightarg=text, procedure=text_sx_eq, commutator = #=);

SELECT * FROM s WHERE text_sx_eq(nm, 'john');

SELECT * FROM s WHERE s.nm #= 'john';

SELECT * FROM s WHERE difference(s.nm, 'john') > 2;