diff options
Diffstat (limited to 'doc/src/sgml/datatype.sgml')
| -rw-r--r-- | doc/src/sgml/datatype.sgml | 28 |
1 files changed, 20 insertions, 8 deletions
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml index fb813d70423..48dfe0a9c47 100644 --- a/doc/src/sgml/datatype.sgml +++ b/doc/src/sgml/datatype.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.226 2008/03/30 04:08:14 neilc Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.227 2008/05/16 16:31:01 tgl Exp $ --> <chapter id="datatype"> <title id="datatype-title">Data Types</title> @@ -3298,18 +3298,17 @@ SELECT * FROM test; SELECT 'a fat cat sat on a mat and ate a fat rat'::tsvector; tsvector ---------------------------------------------------- - 'a' 'on' 'and' 'ate' 'cat' 'fat' 'mat' 'rat' 'sat' + 'a' 'and' 'ate' 'cat' 'fat' 'mat' 'on' 'rat' 'sat' </programlisting> - (As the example shows, the sorting is first by length and then - alphabetically, but that detail is seldom important.) To represent + To represent lexemes containing whitespace or punctuation, surround them with quotes: <programlisting> SELECT $$the lexeme ' ' contains spaces$$::tsvector; tsvector ------------------------------------------- - 'the' ' ' 'lexeme' 'spaces' 'contains' + ' ' 'contains' 'lexeme' 'spaces' 'the' </programlisting> (We use dollar-quoted string literals in this example and the next one, @@ -3320,7 +3319,7 @@ SELECT $$the lexeme ' ' contains spaces$$::tsvector; SELECT $$the lexeme 'Joe''s' contains a quote$$::tsvector; tsvector ------------------------------------------------ - 'a' 'the' 'Joe''s' 'quote' 'lexeme' 'contains' + 'Joe''s' 'a' 'contains' 'lexeme' 'quote' 'the' </programlisting> Optionally, integer <firstterm>position(s)</> @@ -3330,7 +3329,7 @@ SELECT $$the lexeme 'Joe''s' contains a quote$$::tsvector; SELECT 'a:1 fat:2 cat:3 sat:4 on:5 a:6 mat:7 and:8 ate:9 a:10 fat:11 rat:12'::tsvector; tsvector ------------------------------------------------------------------------------- - 'a':1,6,10 'on':5 'and':8 'ate':9 'cat':3 'fat':2,11 'mat':7 'rat':12 'sat':4 + 'a':1,6,10 'and':8 'ate':9 'cat':3 'fat':2,11 'mat':7 'on':5 'rat':12 'sat':4 </programlisting> A position normally indicates the source word's location in the @@ -3369,7 +3368,7 @@ SELECT 'a:1A fat:2B,4C cat:5D'::tsvector; select 'The Fat Rats'::tsvector; tsvector -------------------- - 'Fat' 'The' 'Rats' + 'Fat' 'Rats' 'The' </programlisting> For most English-text-searching applications the above words would @@ -3440,6 +3439,19 @@ SELECT 'fat:ab & cat'::tsquery; </para> <para> + Also, lexemes in a <type>tsquery</type> can be labeled with <literal>*</> + to specify prefix matching: +<programlisting> +SELECT 'super:*'::tsquery; + tsquery +----------- + 'super':* +</programlisting> + This query will match any word in a <type>tsvector</> that begins + with <quote>super</>. + </para> + + <para> Quoting rules for lexemes are the same as described above for lexemes in <type>tsvector</>; and, as with <type>tsvector</>, any required normalization of words must be done before putting |