1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
|
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>7.15.19. snippet_html — Groonga v10.1.1-31-g1e46ba6 documentation</title>
<link rel="stylesheet" href="../../_static/groonga.css" type="text/css" />
<link rel="stylesheet" href="../../_static/pygments.css" type="text/css" />
<script id="documentation_options" data-url_root="../../" src="../../_static/documentation_options.js"></script>
<script src="../../_static/jquery.js"></script>
<script src="../../_static/underscore.js"></script>
<script src="../../_static/doctools.js"></script>
<script src="../../_static/language_data.js"></script>
<link rel="shortcut icon" href="../../_static/favicon.ico"/>
<link rel="index" title="Index" href="../../genindex.html" />
<link rel="search" title="Search" href="../../search.html" />
<link rel="next" title="7.15.20. string_length" href="string_length.html" />
<link rel="prev" title="7.15.18. rand" href="rand.html" />
</head><body>
<div class="header">
<h1 class="title">
<a id="top-link" href="../../index.html">
<span class="project">groonga</span>
<span class="separator">-</span>
<span class="description">An open-source fulltext search engine and column store.</span>
</a>
</h1>
<div class="other-language-links">
<ul>
<li><a href="../../../../ja/html/reference/functions/snippet_html.html">日本語</a></li>
</ul>
</div>
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../../genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="string_length.html" title="7.15.20. string_length"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="rand.html" title="7.15.18. rand"
accesskey="P">previous</a> |</li>
<li class="nav-item nav-item-0"><a href="../../index.html">Groonga v10.1.1-31-g1e46ba6 documentation</a> »</li>
<li class="nav-item nav-item-1"><a href="../../reference.html" ><span class="section-number">7. </span>Reference manual</a> »</li>
<li class="nav-item nav-item-2"><a href="../function.html" accesskey="U"><span class="section-number">7.15. </span>Function</a> »</li>
<li class="nav-item nav-item-this"><a href=""><span class="section-number">7.15.19. </span><code class="docutils literal notranslate"><span class="pre">snippet_html</span></code></a></li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<div class="section" id="snippet-html">
<h1><span class="section-number">7.15.19. </span><code class="docutils literal notranslate"><span class="pre">snippet_html</span></code><a class="headerlink" href="#snippet-html" title="Permalink to this headline">¶</a></h1>
<div class="section" id="summary">
<h2><span class="section-number">7.15.19.1. </span>Summary<a class="headerlink" href="#summary" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal notranslate"><span class="pre">snippet_html</span></code> extracts snippets of target text around search
keywords (<code class="docutils literal notranslate"><span class="pre">KWIC</span></code>. <code class="docutils literal notranslate"><span class="pre">KeyWord</span> <span class="pre">In</span> <span class="pre">Context</span></code>). The snippets are prepared
for embedding HTML. Special characters such as <code class="docutils literal notranslate"><span class="pre"><</span></code> and <code class="docutils literal notranslate"><span class="pre">></span></code> are
escapsed as <code class="docutils literal notranslate"><span class="pre">&lt;</span></code> and <code class="docutils literal notranslate"><span class="pre">&gt;</span></code>. Keyword is surrounded with <code class="docutils literal notranslate"><span class="pre"><span</span>
<span class="pre">class="keyword"></span></code> and <code class="docutils literal notranslate"><span class="pre"></span></span></code>. For example, a snippet of <code class="docutils literal notranslate"><span class="pre">I</span> <span class="pre">am</span> <span class="pre">a</span>
<span class="pre">groonga</span> <span class="pre">user.</span> <span class="pre"><3</span></code> for keyword <code class="docutils literal notranslate"><span class="pre">groonga</span></code> is <code class="docutils literal notranslate"><span class="pre">I</span> <span class="pre">am</span> <span class="pre">a</span> <span class="pre"><span</span>
<span class="pre">class="keyword">groonga</span></span> <span class="pre">user.</span> <span class="pre">&lt;3</span></code>.</p>
</div>
<div class="section" id="syntax">
<h2><span class="section-number">7.15.19.2. </span>Syntax<a class="headerlink" href="#syntax" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal notranslate"><span class="pre">snippet_html</span></code> has only one parameter:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>snippet_html(column)
</pre></div>
</div>
<p><code class="docutils literal notranslate"><span class="pre">snippet_html</span></code> has many parameters internally but they can’t be
specified for now. You will be able to custom those parameters soon.</p>
</div>
<div class="section" id="usage">
<h2><span class="section-number">7.15.19.3. </span>Usage<a class="headerlink" href="#usage" title="Permalink to this headline">¶</a></h2>
<p>Here are a schema definition and sample data to show usage.</p>
<p>Execution example:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>table_create Documents TABLE_NO_KEY
# [[0, 1337566253.89858, 0.000355720520019531], true]
column_create Documents content COLUMN_SCALAR Text
# [[0, 1337566253.89858, 0.000355720520019531], true]
table_create Terms TABLE_PAT_KEY ShortText --default_tokenizer TokenBigram --normalizer NormalizerAuto
# [[0, 1337566253.89858, 0.000355720520019531], true]
column_create Terms documents_content_index COLUMN_INDEX|WITH_POSITION Documents content
# [[0, 1337566253.89858, 0.000355720520019531], true]
load --table Documents
[
["content"],
["Groonga is a fast and accurate full text search engine based on inverted index. One of the characteristics of groonga is that a newly registered document instantly appears in search results. Also, groonga allows updates without read locks. These characteristics result in superior performance on real-time applications."],
["Groonga is also a column-oriented database management system (DBMS). Compared with well-known row-oriented systems, such as MySQL and PostgreSQL, column-oriented systems are more suited for aggregate queries. Due to this advantage, groonga can cover weakness of row-oriented systems."]
]
# [[0, 1337566253.89858, 0.000355720520019531], 2]
</pre></div>
</div>
<p><code class="docutils literal notranslate"><span class="pre">snippet_html</span></code> can be used in only <code class="docutils literal notranslate"><span class="pre">--output_columns</span></code> in
<a class="reference internal" href="../commands/select.html"><span class="doc">select</span></a>.</p>
<p>You also need to specify <code class="docutils literal notranslate"><span class="pre">--query</span></code> and/or <code class="docutils literal notranslate"><span class="pre">--filter</span></code>. Keywords are
extracted from <code class="docutils literal notranslate"><span class="pre">--query</span></code> and <code class="docutils literal notranslate"><span class="pre">--filter</span></code> arguments.</p>
<p>The following example uses <code class="docutils literal notranslate"><span class="pre">--query</span> <span class="pre">"fast</span> <span class="pre">performance"</span></code>. In this
case, <code class="docutils literal notranslate"><span class="pre">fast</span></code> and <code class="docutils literal notranslate"><span class="pre">performance</span></code> are used as keywords.</p>
<p>Execution example:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>select Documents --output_columns "snippet_html(content)" --command_version 2 --match_columns content --query "fast performance"
# [
# [
# 0,
# 1337566253.89858,
# 0.000355720520019531
# ],
# [
# [
# [
# 1
# ],
# [
# [
# "snippet_html",
# null
# ]
# ],
# [
# [
# "Groonga is a <span class=\"keyword\">fast</span> and accurate full text search engine based on inverted index. One of the characteristics of groonga is that a newly registered document instantly appears in search results. Also, gro",
# "onga allows updates without read locks. These characteristics result in superior <span class=\"keyword\">performance</span> on real-time applications."
# ]
# ]
# ]
# ]
# ]
</pre></div>
</div>
<p><code class="docutils literal notranslate"><span class="pre">--query</span> <span class="pre">"fast</span> <span class="pre">performance"</span></code> matches to only the first record’s
content. <code class="docutils literal notranslate"><span class="pre">snippet_html(content)</span></code> extracts two text parts that
include the keywords <code class="docutils literal notranslate"><span class="pre">fast</span></code> or <code class="docutils literal notranslate"><span class="pre">performance</span></code> and surrounds the
keywords with <code class="docutils literal notranslate"><span class="pre"><span</span> <span class="pre">class="keyword"></span></code> and <code class="docutils literal notranslate"><span class="pre"></span></span></code>.</p>
<p>The max number of text parts is 3. If there are 4 or more text parts
that include the keywords, only the leading 3 parts are only used.</p>
<p>The max size of a text part is 200byte. The unit is bytes not
characters. The size doesn’t include inserted <code class="docutils literal notranslate"><span class="pre"><span</span> <span class="pre">class="keyword"></span></code>
and <code class="docutils literal notranslate"><span class="pre"></span></span></code>.</p>
<p>Both the max number of text parts and the max size of a text part
aren’t customizable.</p>
<p>You can specify string literal instead of column.</p>
<p>Execution example:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>select Documents --output_columns 'snippet_html("Groonga is very fast fulltext search engine.")' --command_version 2 --match_columns content --query "fast performance"
# [
# [
# 0,
# 1337566253.89858,
# 0.000355720520019531
# ],
# [
# [
# [
# 1
# ],
# [
# [
# "snippet_html",
# null
# ]
# ],
# [
# [
# "Groonga is very <span class=\"keyword\">fast</span> fulltext search engine."
# ]
# ]
# ]
# ]
# ]
</pre></div>
</div>
</div>
<div class="section" id="return-value">
<h2><span class="section-number">7.15.19.4. </span>Return value<a class="headerlink" href="#return-value" title="Permalink to this headline">¶</a></h2>
<p><code class="docutils literal notranslate"><span class="pre">snippet_html</span></code> returns an array of string or <code class="docutils literal notranslate"><span class="pre">null</span></code>. If
<code class="docutils literal notranslate"><span class="pre">snippet_html</span></code> can’t find any snippets, it returns <code class="docutils literal notranslate"><span class="pre">null</span></code>.</p>
<p>An element of array is a snippet:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>[SNIPPET1, SNIPPET2, SNIPPET3]
</pre></div>
</div>
<p>A snippet includes one or more keywords. The max byte size of a
snippet except <code class="docutils literal notranslate"><span class="pre"><span</span> <span class="pre">class="keyword"></span></code> and <code class="docutils literal notranslate"><span class="pre"></span></span></code> is
200byte. The unit isn’t the number of characters.</p>
<p>The array size is larger than or equal to 0 and less than or equal
to 3. The max size 3 will be customizable soon.</p>
</div>
<div class="section" id="todo">
<h2><span class="section-number">7.15.19.5. </span>TODO<a class="headerlink" href="#todo" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li><p>Make the max number of text parts customizable.</p></li>
<li><p>Make the max size of a text part customizable.</p></li>
<li><p>Make keywords customizable.</p></li>
<li><p>Make tag that surrounds a keyword customizable.</p></li>
<li><p>Make normalization customizable.</p></li>
<li><p>Support options by object literal.</p></li>
</ul>
</div>
<div class="section" id="see-also">
<h2><span class="section-number">7.15.19.6. </span>See also<a class="headerlink" href="#see-also" title="Permalink to this headline">¶</a></h2>
<ul class="simple">
<li><p><a class="reference internal" href="../commands/select.html"><span class="doc">select</span></a></p></li>
</ul>
</div>
</div>
<div class="clearer"></div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
<div class="sphinxsidebarwrapper">
<h3><a href="../../index.html">Table of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">7.15.19. <code class="docutils literal notranslate"><span class="pre">snippet_html</span></code></a><ul>
<li><a class="reference internal" href="#summary">7.15.19.1. Summary</a></li>
<li><a class="reference internal" href="#syntax">7.15.19.2. Syntax</a></li>
<li><a class="reference internal" href="#usage">7.15.19.3. Usage</a></li>
<li><a class="reference internal" href="#return-value">7.15.19.4. Return value</a></li>
<li><a class="reference internal" href="#todo">7.15.19.5. TODO</a></li>
<li><a class="reference internal" href="#see-also">7.15.19.6. See also</a></li>
</ul>
</li>
</ul>
<h4>Previous topic</h4>
<p class="topless"><a href="rand.html"
title="previous chapter"><span class="section-number">7.15.18. </span>rand</a></p>
<h4>Next topic</h4>
<p class="topless"><a href="string_length.html"
title="next chapter"><span class="section-number">7.15.20. </span><code class="docutils literal notranslate"><span class="pre">string_length</span></code></a></p>
<div id="searchbox" style="display: none" role="search">
<h3 id="searchlabel">Quick search</h3>
<div class="searchformwrapper">
<form class="search" action="../../search.html" method="get">
<input type="text" name="q" aria-labelledby="searchlabel" />
<input type="submit" value="Go" />
</form>
</div>
</div>
<script>$('#searchbox').show(0);</script>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../../genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="string_length.html" title="7.15.20. string_length"
>next</a> |</li>
<li class="right" >
<a href="rand.html" title="7.15.18. rand"
>previous</a> |</li>
<li class="nav-item nav-item-0"><a href="../../index.html">Groonga v10.1.1-31-g1e46ba6 documentation</a> »</li>
<li class="nav-item nav-item-1"><a href="../../reference.html" ><span class="section-number">7. </span>Reference manual</a> »</li>
<li class="nav-item nav-item-2"><a href="../function.html" ><span class="section-number">7.15. </span>Function</a> »</li>
<li class="nav-item nav-item-this"><a href=""><span class="section-number">7.15.19. </span><code class="docutils literal notranslate"><span class="pre">snippet_html</span></code></a></li>
</ul>
</div>
<div class="footer" role="contentinfo">
© Copyright 2009-2021, Brazil, Inc.
</div>
</body>
</html>
|
