RETURNS tsvector
BEGIN ATOMIC
  SELECT to_tsvector('simple',
                     string_agg(array_to_string(daitch_mokotoff(n), ' '), ' '))
  FROM regexp_split_to_table(v_name, '\s+') AS n;
END;

CREATE FUNCTION soundex_tsquery(v_name text) RETURNS tsquery
BEGIN ATOMIC
  SELECT string_agg('(' || array_to_string(daitch_mokotoff(n), '|') || ')', '&')::tsquery
  FROM regexp_split_to_table(v_name, '\s+') AS n;
END;

CREATE TABLE s (nm text);
CREATE INDEX ix_s_txt ON s USING gin (soundex_tsvector(nm)) WITH (fastupdate = off);

INSERT INTO s (nm) VALUES
  ('John Doe'),
  ('Jane Roe'),
  ('Public John Q.'),
  ('George Best'),
  ('John Yamson');

SELECT * FROM s WHERE soundex_tsvector(nm) @@ soundex_tsquery('john');
SELECT * FROM s WHERE soundex_tsvector(nm) @@ soundex_tsquery('jane doe');
SELECT * FROM s WHERE soundex_tsvector(nm) @@ soundex_tsquery('john public');
SELECT * FROM s WHERE soundex_tsvector(nm) @@ soundex_tsquery('besst, giorgio');
SELECT * FROM s WHERE soundex_tsvector(nm) @@ soundex_tsquery('Jameson John');
</programlisting>

  <para>
   If it is desired to avoid recalculation of soundex codes during index
   rechecks, an index on a separate column can be used instead of an index on
   an expression.  A stored generated column can be used for this; see
   <xref linkend="ddl-generated-columns"/>.
  </para>
 </sect2>

 <sect2 id="fuzzystrmatch-levenshtein">
  <title>Levenshtein</title>

  <para>
   This function calculates the Levenshtein distance between two strings:
  </para>

  <indexterm>
   <primary>levenshtein</primary>
  </indexterm>

  <indexterm>
   <primary>levenshtein_less_equal</primary>
  </indexterm>

<synopsis>
levenshtein(source text, target text, ins_cost int, del_cost int, sub_cost int) returns int
levenshtein(source text, target text) returns int
levenshtein_less_equal(source text, target text, ins_cost int, del_cost int, sub_cost int, max_d int) returns int
levenshtein_less_equal(source text, target text, max_d int) returns int
</synopsis>

  <para>
   Both <literal>source</literal> and <literal>target</literal> can be any
   non-null string, with a maximum of 255 characters.  The cost parameters
   specify how much to charge for a character insertion, deletion, or
   substitution, respectively.  You can omit the cost parameters, as in
   the second version of the function; in that case they all default to 1.
  </para>

  <para>
   <function>levenshtein_less_equal</function> is an accelerated version of the
   Levenshtein function for use when only small distances are of interest.
   If the actual distance is less than or equal to <literal>max_d</literal>,
   then