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Lu, Huayi e6fa411af0 DWS DEV 830.201 version 
Reviewed-by: Pruthi, Vineet <vineet.pruthi@t-systems.com>
Co-authored-by: Lu, Huayi <luhuayi@huawei.com>
Co-committed-by: Lu, Huayi <luhuayi@huawei.com>
2024-05-16 07:24:04 +00:00

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<a name="EN-US_TOPIC_0000001764244341"></a><a name="EN-US_TOPIC_0000001764244341"></a>
<h1 class="topictitle1">Example: Processing the RoaringBitmap Result Set on Application Then Importing It to GaussDB(DWS)</h1>
<div id="body0000001764244341"><p id="EN-US_TOPIC_0000001764244341__p78684916432">GaussDB(DWS) 8.1.3 and later versions support the RoaringBitmap function. When using the Java language to perform secondary development based on <span id="EN-US_TOPIC_0000001764244341__text7947937">GaussDB(DWS)</span>, you can use the CopyManager interface to import a small amount of RoaringBitmap data to GaussDB(DWS).</p>
<div class="note" id="EN-US_TOPIC_0000001764244341__note13960714103"><img src="public_sys-resources/note_3.0-en-us.png"><span class="notetitle"> </span><div class="notebody"><p id="EN-US_TOPIC_0000001764244341__p89602131020">To import a large amount of RoaringBitmap data, computing power of the application side needs to be increased. Otherwise, the import performance will be affected.</p>
</div></div>
<div class="section" id="EN-US_TOPIC_0000001764244341__section3584189114810"><h4 class="sectiontitle">Processing RoaringBitmap Data</h4><ol id="EN-US_TOPIC_0000001764244341__ol114561911104811"><li id="EN-US_TOPIC_0000001764244341__li15456411114813"><span>Visit <a href="https://mvnrepository.com/artifact/org.roaringbitmap/RoaringBitmap" target="_blank" rel="noopener noreferrer">Maven</a> to download the open-source RoaringBitmap JAR package. Version 0.9.15 is recommended.</span><p><div class="p" id="EN-US_TOPIC_0000001764244341__p198479241337">The dependency items of the POM file are configured as follows:<div class="codecoloring" codetype="Java" id="EN-US_TOPIC_0000001764244341__screen64849241738"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
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<span class="w"> </span><span class="o">&lt;</span><span class="n">dependency</span><span class="o">&gt;</span>
<span class="w"> </span><span class="o">&lt;</span><span class="n">groupId</span><span class="o">&gt;</span><span class="n">org</span><span class="p">.</span><span class="na">roaringbitmap</span><span class="o">&lt;/</span><span class="n">groupId</span><span class="o">&gt;</span>
<span class="w"> </span><span class="o">&lt;</span><span class="n">artifactId</span><span class="o">&gt;</span><span class="n">RoaringBitmap</span><span class="o">&lt;/</span><span class="n">artifactId</span><span class="o">&gt;</span>
<span class="w"> </span><span class="o">&lt;</span><span class="n">version</span><span class="o">&gt;</span><span class="mf">0.9.15</span><span class="o">&lt;/</span><span class="n">version</span><span class="o">&gt;</span>
<span class="w"> </span><span class="o">&lt;/</span><span class="n">dependency</span><span class="o">&gt;</span>
<span class="w"> </span><span class="o">&lt;/</span><span class="n">dependencies</span><span class="o">&gt;</span>
</pre></div></td></tr></table></div>
</div>
</div>
<p id="EN-US_TOPIC_0000001764244341__p1148412249316"><span><img id="EN-US_TOPIC_0000001764244341__image74844241537" src="figure/en-us_image_0000001764383893.png"></span></p>
</p></li><li id="EN-US_TOPIC_0000001764244341__li112341295489"><span>Invoke the JAR package to convert data to the RoaringBitmap type.</span><p><p id="EN-US_TOPIC_0000001764244341__p733173310321">The general process is to declare a Roaring bitmap, call the add() method to convert data of the int type into the Roaringbitmap type, and then serialize the converted data. The sample code is as follows:</p>
<div class="codecoloring" codetype="Java" id="EN-US_TOPIC_0000001764244341__screen1077571112819"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal">1</span>
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<span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="mi">10000000</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">rr2</span><span class="p">.</span><span class="na">add</span><span class="p">(</span><span class="n">i</span><span class="p">);</span>
<span class="p">}</span>
<span class="n">ByteArrayOutputStream</span><span class="w"> </span><span class="n">a</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ByteArrayOutputStream</span><span class="p">();</span>
<span class="n">DataOutputStream</span><span class="w"> </span><span class="n">b</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">DataOutputStream</span><span class="p">(</span><span class="n">a</span><span class="p">);</span>
<span class="n">rr2</span><span class="p">.</span><span class="na">serialize</span><span class="p">(</span><span class="n">b</span><span class="p">);</span>
</pre></div></td></tr></table></div>
</div>
</p></li></ol>
</div>
<div class="section" id="EN-US_TOPIC_0000001764244341__section4385546082"><h4 class="sectiontitle">Data Import</h4><p id="EN-US_TOPIC_0000001764244341__p141611447981">Invoke CopyManager to import data to the database. In this way, a small amount of RoaringBitmap data can be imported to the database without having to be stored locally.</p>
<div class="codecoloring" codetype="Java" id="EN-US_TOPIC_0000001764244341__screen11235143081418"><div class="highlight"><table class="highlighttable"><tr><td class="linenos"><div class="linenodiv"><pre><span class="normal"> 1</span>
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<span class="normal">113</span></pre></div></td><td class="code"><div><pre><span></span><span class="c1">//gsjdbc4.jar is used as an example.</span>
<span class="kn">package</span><span class="w"> </span><span class="nn">rb_demo</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">org.postgresql.copy.CopyManager</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">org.postgresql.core.BaseConnection</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">org.roaringbitmap.RoaringBitmap</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.io.ByteArrayInputStream</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.io.ByteArrayOutputStream</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.io.DataOutputStream</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.io.IOException</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.io.InputStream</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.io.StringReader</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.sql.Connection</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.sql.DriverManager</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.sql.PreparedStatement</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.sql.ResultSet</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.sql.SQLException</span><span class="p">;</span>
<span class="kn">import</span><span class="w"> </span><span class="nn">java.sql.Statement</span><span class="p">;</span>
<span class="kd">public</span><span class="w"> </span><span class="kd">class</span> <span class="nc">rb_demo</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="kd">private</span><span class="w"> </span><span class="kd">static</span><span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">hexStr</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;0123456789ABCDEF&quot;</span><span class="p">;</span>
<span class="w"> </span>
<span class="w"> </span><span class="kd">public</span><span class="w"> </span><span class="kd">static</span><span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="nf">bytesToHex</span><span class="p">(</span><span class="kt">byte</span><span class="o">[]</span><span class="w"> </span><span class="n">bytes</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">StringBuffer</span><span class="w"> </span><span class="n">sb</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">StringBuffer</span><span class="p">();</span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">0</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="n">bytes</span><span class="p">.</span><span class="na">length</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">hex</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">Integer</span><span class="p">.</span><span class="na">toHexString</span><span class="p">(</span><span class="n">bytes</span><span class="o">[</span><span class="n">i</span><span class="o">]</span><span class="w"> </span><span class="o">&amp;</span><span class="w"> </span><span class="mh">0xFF</span><span class="p">);</span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">hex</span><span class="p">.</span><span class="na">length</span><span class="p">()</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="mi">2</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">sb</span><span class="p">.</span><span class="na">append</span><span class="p">(</span><span class="mi">0</span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="n">sb</span><span class="p">.</span><span class="na">append</span><span class="p">(</span><span class="n">hex</span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">sb</span><span class="p">.</span><span class="na">toString</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="kd">public</span><span class="w"> </span><span class="kd">static</span><span class="w"> </span><span class="n">Connection</span><span class="w"> </span><span class="nf">GetConnection</span><span class="p">(</span><span class="n">String</span><span class="w"> </span><span class="n">username</span><span class="p">,</span><span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">passwd</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">driver</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;org.postgresql.Driver&quot;</span><span class="p">;</span>
<span class="n">String</span><span class="w"> </span><span class="n">sourceURL</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;jdbc:postgresql://10.185.180.161: 8000/gaussdb&quot;</span><span class="p">;</span><span class="w"> </span><span class="c1">//Database URL</span>
<span class="w"> </span><span class="n">Connection</span><span class="w"> </span><span class="n">conn</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="kc">null</span><span class="p">;</span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="c1">//Load the database driver.</span>
<span class="w"> </span><span class="n">Class</span><span class="p">.</span><span class="na">forName</span><span class="p">(</span><span class="n">driver</span><span class="p">).</span><span class="na">newInstance</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">Exception</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
<span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="kc">null</span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="c1">//Establish a connection to the database.</span>
<span class="w"> </span><span class="n">conn</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">DriverManager</span><span class="p">.</span><span class="na">getConnection</span><span class="p">(</span><span class="n">sourceURL</span><span class="p">,</span><span class="w"> </span><span class="n">username</span><span class="p">,</span><span class="w"> </span><span class="n">passwd</span><span class="p">);</span>
<span class="w"> </span><span class="n">System</span><span class="p">.</span><span class="na">out</span><span class="p">.</span><span class="na">println</span><span class="p">(</span><span class="s">&quot;Connection succeed!&quot;</span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">Exception</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
<span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="kc">null</span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="k">return</span><span class="w"> </span><span class="n">conn</span><span class="p">;</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="kd">public</span><span class="w"> </span><span class="kd">static</span><span class="w"> </span><span class="kt">void</span><span class="w"> </span><span class="nf">main</span><span class="p">(</span><span class="n">String</span><span class="o">[]</span><span class="w"> </span><span class="n">args</span><span class="p">)</span><span class="w"> </span><span class="kd">throws</span><span class="w"> </span><span class="n">IOException</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">RoaringBitmap</span><span class="w"> </span><span class="n">rr2</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">RoaringBitmap</span><span class="p">();</span>
<span class="w"> </span><span class="k">for</span><span class="w"> </span><span class="p">(</span><span class="kt">int</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="mi">1</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="w"> </span><span class="o">&lt;</span><span class="w"> </span><span class="mi">10000000</span><span class="p">;</span><span class="w"> </span><span class="n">i</span><span class="o">++</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">rr2</span><span class="p">.</span><span class="na">add</span><span class="p">(</span><span class="n">i</span><span class="p">);</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span>
<span class="w"> </span><span class="n">ByteArrayOutputStream</span><span class="w"> </span><span class="n">a</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">ByteArrayOutputStream</span><span class="p">();</span>
<span class="w"> </span>
<span class="w"> </span><span class="n">DataOutputStream</span><span class="w"> </span><span class="n">b</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">DataOutputStream</span><span class="p">(</span><span class="n">a</span><span class="p">);</span>
<span class="w"> </span><span class="n">rr2</span><span class="p">.</span><span class="na">serialize</span><span class="p">(</span><span class="n">b</span><span class="p">);</span>
<span class="n">Connection</span><span class="w"> </span><span class="n">conn</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">GetConnection</span><span class="p">(</span><span class="s">&quot;test&quot;</span><span class="p">,</span><span class="w"> </span><span class="s">&quot;Gauss_234&quot;</span><span class="p">);</span><span class="w"> </span><span class="c1">//User name and password.</span>
<span class="w"> </span><span class="n">Statement</span><span class="w"> </span><span class="n">pstmt</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="kc">null</span><span class="p">;</span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">conn</span><span class="p">.</span><span class="na">setAutoCommit</span><span class="p">(</span><span class="kc">true</span><span class="p">);</span>
<span class="w"> </span><span class="n">pstmt</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">conn</span><span class="p">.</span><span class="na">createStatement</span><span class="p">();</span>
<span class="w"> </span><span class="n">pstmt</span><span class="p">.</span><span class="na">execute</span><span class="p">(</span><span class="s">&quot;drop table if exists t_rb&quot;</span><span class="p">);</span>
<span class="w"> </span><span class="n">pstmt</span><span class="p">.</span><span class="na">execute</span><span class="p">(</span><span class="s">&quot;create table t_rb(c1 int, c2 roaringbitmap) distribute by hash (c1);&quot;</span><span class="p">);</span>
<span class="w"> </span><span class="n">StringReader</span><span class="w"> </span><span class="n">sr</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="kc">null</span><span class="p">;</span>
<span class="w"> </span><span class="n">CopyManager</span><span class="w"> </span><span class="n">cm</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="kc">null</span><span class="p">;</span>
<span class="w"> </span><span class="n">cm</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">CopyManager</span><span class="p">((</span><span class="n">BaseConnection</span><span class="p">)</span><span class="w"> </span><span class="n">conn</span><span class="p">);</span>
<span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">delimiter</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;|&quot;</span><span class="p">;</span>
<span class="w"> </span><span class="n">StringBuffer</span><span class="w"> </span><span class="n">tuples</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">StringBuffer</span><span class="p">();</span>
<span class="w"> </span><span class="n">tuples</span><span class="p">.</span><span class="na">append</span><span class="p">(</span><span class="s">&quot;1&quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">delimiter</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="s">&quot;\\x&quot;</span><span class="w"> </span><span class="o">+</span><span class="w"> </span><span class="n">bytesToHex</span><span class="p">(</span><span class="n">a</span><span class="p">.</span><span class="na">toByteArray</span><span class="p">()));</span>
<span class="w"> </span><span class="n">StringBuffer</span><span class="w"> </span><span class="n">sb</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">StringBuffer</span><span class="p">();</span>
<span class="w"> </span><span class="n">sb</span><span class="p">.</span><span class="na">append</span><span class="p">(</span><span class="n">tuples</span><span class="p">.</span><span class="na">toString</span><span class="p">());</span>
<span class="w"> </span><span class="n">sr</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="k">new</span><span class="w"> </span><span class="n">StringReader</span><span class="p">(</span><span class="n">tuples</span><span class="p">.</span><span class="na">toString</span><span class="p">());</span>
<span class="w"> </span><span class="n">String</span><span class="w"> </span><span class="n">sql</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="s">&quot;copy t_rb from STDIN with (delimiter '|', NOESCAPING)&quot;</span><span class="p">;</span>
<span class="w"> </span>
<span class="kt">long</span><span class="w"> </span><span class="n">rows</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">cm</span><span class="p">.</span><span class="na">copyIn</span><span class="p">(</span><span class="n">sql</span><span class="p">,</span><span class="w"> </span><span class="n">sr</span><span class="p">);</span><span class="c1">//Execute the COPY command to save data to the database.</span>
<span class="w"> </span><span class="n">pstmt</span><span class="p">.</span><span class="na">close</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">SQLException</span><span class="w"> </span><span class="n">e</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="p">(</span><span class="n">pstmt</span><span class="w"> </span><span class="o">!=</span><span class="w"> </span><span class="kc">null</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="k">try</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">pstmt</span><span class="p">.</span><span class="na">close</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span><span class="w"> </span><span class="k">catch</span><span class="w"> </span><span class="p">(</span><span class="n">SQLException</span><span class="w"> </span><span class="n">e1</span><span class="p">)</span><span class="w"> </span><span class="p">{</span>
<span class="w"> </span><span class="n">e1</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="n">e</span><span class="p">.</span><span class="na">printStackTrace</span><span class="p">();</span>
<span class="w"> </span><span class="p">}</span>
<span class="w"> </span><span class="p">}</span>
<span class="p">}</span>
</pre></div></td></tr></table></div>
</div>
</div>
</div>
<div>
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<div class="parentlink"><strong>Parent topic:</strong> <a href="dws_04_0088.html">JDBC-Based Development</a></div>
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