- <para>Queries using simple terms.
- <screen>
- dylan
- "bob dylan"
- </screen>
- </para>
- <para>Boolean operators.
- <screen>
- @or "dylan" "zimmerman"
- @and @or dylan zimmerman when
- @and when @or dylan zimmerman
- </screen>
- </para>
- <para>
- Reference to result sets.
- <screen>
- @set Result-1
- @and @set seta setb
- </screen>
- </para>
- <para>
- Attributes for terms.
- <screen>
- @attr 1=4 computer
- @attr 1=4 @attr 4=1 "self portrait"
- @attr exp1 @attr 1=1 CategoryList
- @attr gils 1=2008 Copenhagen
- @attr 1=/book/title computer
- </screen>
- </para>
- <para>
- Proximity.
- <screen>
- @prox 0 3 1 2 k 2 dylan zimmerman
- </screen>
- <note><para>
- Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
- distance, ordered, relation, which-code and unit-code, in that
- order. So:
- <itemizedlist>
- <listitem><para>
- exclusion = 0: the proximity condition must hold
- </para></listitem>
- <listitem><para>
- distance = 3: the terms must be three units apart
- </para></listitem>
- <listitem><para>
- ordered = 1: they must occur in the order they are specified
- </para></listitem>
- <listitem><para>
- relation = 2: lessThanOrEqual (to the distance of 3 units)
- </para></listitem>
- <listitem><para>
- which-code is ``known'', so the standard unit-codes are used
- </para></listitem>
- <listitem><para>
- unit-code = 2: word.
- </para></listitem>
- </itemizedlist>
- So the whole proximity query means that the words
- <literal>dylan</literal> and <literal>zimmerman</literal> must
- both occur in the record, in that order, differing in position
- by three or fewer words (i.e. with two or fewer words between
- them.) The query would find ``Bob Dylan, aka. Robert
- Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
- since the distance in this case is four.
- </para></note>
- </para>
- <para>
- Specifying term type.
- <screen>
- @term string "a UTF-8 string, maybe?"
- </screen>
- </para>
- <para>Mixed queries
- <screen>
- @or @and bob dylan @set Result-1
-
- @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
-
- @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109
+ <example><title>PQF queries using simple terms</title>
+ <para>
+ <screen>
+ dylan
+ "bob dylan"
+ </screen>
+ </para>
+ </example>
+ <example><title>PQF boolean operators</title>
+ <para>
+ <screen>
+ @or "dylan" "zimmerman"
+ @and @or dylan zimmerman when
+ @and when @or dylan zimmerman
+ </screen>
+ </para>
+ </example>
+ <example><title>PQF references to result sets</title>
+ <para>
+ <screen>
+ @set Result-1
+ @and @set seta setb
+ </screen>
+ </para>
+ </example>
+ <example><title>Attributes for terms</title>
+ <para>
+ <screen>
+ @attr 1=4 computer
+ @attr 1=4 @attr 4=1 "self portrait"
+ @attrset exp1 @attr 1=1 CategoryList
+ @attr gils 1=2008 Copenhagen
+ @attr 1=/book/title computer
+ </screen>
+ </para>
+ </example>
+ <example><title>PQF Proximity queries</title>
+ <para>
+ <screen>
+ @prox 0 3 1 2 k 2 dylan zimmerman
+ </screen>
+ <note><para>
+ Here the parameters 0, 3, 1, 2, k and 2 represent exclusion,
+ distance, ordered, relation, which-code and unit-code, in that
+ order. So:
+ <itemizedlist>
+ <listitem><para>
+ exclusion = 0: the proximity condition must hold
+ </para></listitem>
+ <listitem><para>
+ distance = 3: the terms must be three units apart
+ </para></listitem>
+ <listitem><para>
+ ordered = 1: they must occur in the order they are specified
+ </para></listitem>
+ <listitem><para>
+ relation = 2: lessThanOrEqual (to the distance of 3 units)
+ </para></listitem>
+ <listitem><para>
+ which-code is ``known'', so the standard unit-codes are used
+ </para></listitem>
+ <listitem><para>
+ unit-code = 2: word.
+ </para></listitem>
+ </itemizedlist>
+ So the whole proximity query means that the words
+ <literal>dylan</literal> and <literal>zimmerman</literal> must
+ both occur in the record, in that order, differing in position
+ by three or fewer words (i.e. with two or fewer words between
+ them.) The query would find ``Bob Dylan, aka. Robert
+ Zimmerman'', but not ``Bob Dylan, born as Robert Zimmerman''
+ since the distance in this case is four.
+ </para></note>
+ </para>
+ </example>
+ <example><title>PQF specification of search term</title>
+ <para>
+ <screen>
+ @term string "a UTF-8 string, maybe?"
+ </screen>
+ </para>
+ </example>
+ <example><title>PQF mixed queries</title>
+ <para>
+ <screen>
+ @or @and bob dylan @set Result-1
+
+ @attr 4=1 @and @attr 1=1 "bob dylan" @attr 1=4 "slow train coming"
+
+ @and @attr 2=4 @attr gils 1=2038 -114 @attr 2=2 @attr gils 1=2039 -109