<!-- $PostgreSQL: pgsql/doc/src/sgml/textsearch.sgml,v 1.41 2008/03/04 03:17:18 momjian Exp $ -->

<!-- $PostgreSQL: pgsql/doc/src/sgml/textsearch.sgml,v 1.42 2008/03/10 03:01:28 tgl Exp $ -->

<chapter id="textsearch">

<title id="textsearch-title">Full Text Search</title>

dictionary can be used to overcome linguistic problems, for example, to

prevent an English stemmer dictionary from reducing the word 'Paris' to

'pari'. It is enough to have a <literal>Paris paris</literal> line in the

synonym dictionary and put it before the <literal>english_stem</> dictionary:

synonym dictionary and put it before the <literal>english_stem</>

dictionary. For example:

<programlisting>

SELECT * FROM ts_debug('english', 'Paris');

<productname>PostgreSQL</> installation's shared-data directory).

The file format is just one line

per word to be substituted, with the word followed by its synonym,

separated by white space. Blank lines and trailing spaces are ignored,

and upper case is folded to lower case.

separated by white space. Blank lines and trailing spaces are ignored.

</para>

<para>

The <literal>synonym</> template also has an optional parameter

<literal>CaseSensitive</>, which defaults to <literal>false</>. When

<literal>CaseSensitive</> is <literal>false</>, words in the synonym file

are folded to lower case, as are input tokens. When it is

<literal>true</>, words and tokens are not folded to lower case,

but are compared as-is.

</para>

</sect2>

<sect2 id="textsearch-thesaurus">

{

intlen;/* length of syn array */

Syn*syn;

boolcase_sensitive;

}DictSyn;

DictSyn*d;

ListCell*l;

char*filename=NULL;

boolcase_sensitive= false;

FILE*fin;

char*starti,

*starto,

if (pg_strcasecmp("Synonyms",defel->defname)==0)

filename=defGetString(defel);

elseif (pg_strcasecmp("CaseSensitive",defel->defname)==0)

case_sensitive=defGetBoolean(defel);

ereport(ERROR,

(errcode(ERRCODE_INVALID_PARAMETER_VALUE),

}

}

d->syn[cur].in=lowerstr(starti);

d->syn[cur].out=lowerstr(starto);

if (case_sensitive)

{

d->syn[cur].in=pstrdup(starti);

d->syn[cur].out=pstrdup(starto);

}

{

d->syn[cur].in=lowerstr(starti);

d->syn[cur].out=lowerstr(starto);

}

cur++;

d->len=cur;

qsort(d->syn,d->len,sizeof(Syn),compareSyn);

d->case_sensitive=case_sensitive;

PG_RETURN_POINTER(d);

}

if (len <=0||d->len <=0)

PG_RETURN_POINTER(NULL);

key.in=lowerstr_with_len(in,len);

if (d->case_sensitive)

key.in=pnstrdup(in,len);

key.in=lowerstr_with_len(in,len);

key.out=NULL;

found= (Syn*)bsearch(&key,d->syn,d->len,sizeof(Syn),compareSyn);