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Tsvector editing functions

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Adds several tsvector editting function: convert tsvector to/from text array,
set weight for given lexemes, delete lexeme(s), unnest, filter lexemes
with given weights

Author: Stas Kelvich with some editorization by me
Reviewers: Tomas Vondram, Teodor Sigaev
This commit is contained in:
Teodor Sigaev
2016-03-11 19:22:36 +03:00
parent 49635d7b3e
commit 6943a946c7
7 changed files with 933 additions and 18 deletions
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91
doc/src/sgml/func.sgml
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@ -9211,13 +9211,26 @@ CREATE TYPE rainbow AS ENUM ('red', 'orange', 'yellow', 'green', 'blue', 'purple
<indexterm>
<primary>setweight</primary>
</indexterm>
<literal><function>setweight(<type>tsvector</>, <type>"char"</>)</function></literal>
<literal><function>setweight(<replaceable class="PARAMETER">vector</replaceable> <type>tsvector</>, <replaceable class="PARAMETER">weight</replaceable> <type>"char"</>)</function></literal>
</entry>
<entry><type>tsvector</type></entry>
<entry>assign weight to each element of <type>tsvector</></entry>
<entry>assign <replaceable class="PARAMETER">weight</replaceable> to each element of <replaceable class="PARAMETER">vector</replaceable></entry>
<entry><literal>setweight('fat:2,4 cat:3 rat:5B'::tsvector, 'A')</literal></entry>
<entry><literal>'cat':3A 'fat':2A,4A 'rat':5A</literal></entry>
</row>
<row>
<entry>
<indexterm>
<primary>setweight</primary>
<secondary>setweight by filter</secondary>
</indexterm>
<literal><function>setweight(<replaceable class="PARAMETER">vector</replaceable> <type>tsvector</>, <replaceable class="PARAMETER">weight</replaceable> <type>"char"</>, <replaceable class="PARAMETER">lexemes</replaceable> <type>"text"[]</>)</function></literal>
</entry>
<entry><type>tsvector</type></entry>
<entry>assign <replaceable class="PARAMETER">weight</replaceable> to elements of <replaceable class="PARAMETER">vector</replaceable> that are listed in <replaceable class="PARAMETER">lexemes</replaceable> array</entry>
<entry><literal>setweight('fat:2,4 cat:3 rat:5B'::tsvector, 'A', '{cat,rat}')</literal></entry>
<entry><literal>'cat':3A 'fat':2,4 'rat':5A</literal></entry>
</row>
<row>
<entry>
<indexterm>
@ -9230,6 +9243,80 @@ CREATE TYPE rainbow AS ENUM ('red', 'orange', 'yellow', 'green', 'blue', 'purple
<entry><literal>strip('fat:2,4 cat:3 rat:5A'::tsvector)</literal></entry>
<entry><literal>'cat' 'fat' 'rat'</literal></entry>
</row>
<row>
<entry>
<indexterm>
<primary>delete</primary>
<secondary>delete lemexeme</secondary>
</indexterm>
<literal><function>delete(<replaceable class="PARAMETER">vector</replaceable> <type>tsvector</>, <replaceable class="PARAMETER">lexeme</replaceable> <type>text</>)</function></literal>
</entry>
<entry><type>tsvector</type></entry>
<entry>remove given <replaceable class="PARAMETER">lexeme</replaceable> from <replaceable class="PARAMETER">vector</replaceable></entry>
<entry><literal>delete('fat:2,4 cat:3 rat:5A'::tsvector, 'fat')</literal></entry>
<entry><literal>'cat':3 'rat':5A</literal></entry>
</row>
<row>
<entry>
<indexterm>
<primary>delete</primary>
<secondary>delete lemexemes array</secondary>
</indexterm>
<literal><function>delete(<replaceable class="PARAMETER">vector</replaceable> <type>tsvector</>, <replaceable class="PARAMETER">lexemes</replaceable> <type>text[]</>)</function></literal>
</entry>
<entry><type>tsvector</type></entry>
<entry>remove any occurrence of lexemes in <replaceable class="PARAMETER">lexemes</replaceable> array from <replaceable class="PARAMETER">vector</replaceable></entry>
<entry><literal>delete('fat:2,4 cat:3 rat:5A'::tsvector, ARRAY['fat','rat'])</literal></entry>
<entry><literal>'cat':3</literal></entry>
</row>
<row>
<entry>
<indexterm>
<primary>unnest</primary>
</indexterm>
<literal><function>unnest(<type>tsvector</>, OUT <replaceable class="PARAMETER">lexeme</> <type>text</>, OUT <replaceable class="PARAMETER">positions</> <type>smallint[]</>, OUT <replaceable class="PARAMETER">weights</> <type>text</>)</function></literal>
</entry>
<entry><type>setof record</type></entry>
<entry>expand a tsvector to a set of rows</entry>
<entry><literal>unnest('fat:2,4 cat:3 rat:5A'::tsvector)</literal></entry>
<entry><literal>(cat,{3},{D}) ...</literal></entry>
</row>
<row>
<entry>
<indexterm>
<primary>tsvector_to_array</primary>
</indexterm>
<literal><function>tsvector_to_array(<type>tsvector</>)</function></literal>
</entry>
<entry><type>text[]</type></entry>
<entry>convert <type>tsvector</> to array of lexemes</entry>
<entry><literal>tsvector_to_array('fat:2,4 cat:3 rat:5A'::tsvector)</literal></entry>
<entry><literal>{cat,fat,rat}</literal></entry>
</row>
<row>
<entry>
<indexterm>
<primary>array_to_tsvector</primary>
</indexterm>
<literal><function>array_to_tsvector(<type>text[]</>)</function></literal>
</entry>
<entry><type>tsvector</type></entry>
<entry>convert array of lexemes to <type>tsvector</type></entry>
<entry><literal>array_to_tsvector('{fat,cat,rat}'::text[])</literal></entry>
<entry><literal>'fat' 'cat' 'rat'</literal></entry>
</row>
<row>
<entry>
<indexterm>
<primary>filter</primary>
</indexterm>
<literal><function>filter(<replaceable class="PARAMETER">vector</replaceable> <type>tsvector</>, <replaceable class="PARAMETER">weights</replaceable> <type>"char"[]</>)</function></literal>
</entry>
<entry><type>tsvector</type></entry>
<entry>Select only elements with given <replaceable class="PARAMETER">weights</replaceable> from <replaceable class="PARAMETER">vector</replaceable></entry>
<entry><literal>filter('fat:2,4 cat:3b rat:5A'::tsvector, '{a,b}')</literal></entry>
<entry><literal>'cat':3B 'rat':5A</literal></entry>
</row>
<row>
<entry>
<indexterm>

4
doc/src/sgml/textsearch.sgml
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@ -1326,6 +1326,10 @@ FROM (SELECT id, body, q, ts_rank_cd(ti, q) AS rank
</variablelist>
<para>
Full list of <type>tsvector</>-related functions available in <xref linkend="textsearch-functions-table">.
</para>
</sect2>
<sect2 id="textsearch-manipulate-tsquery">